SR71a for FSX Deluxe Operation Guide

Information optimized for Flight Simulator and this model based on the real world SR71 Pilot Manual data.
Note: Development testing is performed on FSX Deluxe. Acceleration Pack is not supported due to unresolved problems with the Throttle and Afterbuner. Although Acceleration Pack is mentioned at times in this document, this does not mean AccPack works properly or is supported. FSX Standard is untested but should work.

Paul R. Varn
Revised Mar. 19, 2013

Contents:

SR71a for FSX Operation Guide based on Freeware release AlphaSim SR71a
Note: Only the AlphaSim 3D model and textures are used. All other files are replaced by this distribution. See the README files which come with this distribution's base installation files and the README included with the current update archive for complete installation and upgrade instructions.
Credits
Features
Weather Environment
Active Sky Settings
Special Gauges
Specifications

Trivia

Lockheed_SR-71A_3view

DESCRIPTION:
Dynamic model replacement for AIR and CFG files for public freeware release of AlphaSim SR71a. Panel with gauges, effects and sounds.

The book "Lockheed SR-71" by Jay Miller provided a wealth of information I didn't have access to before. Thanks to Gary Hall for loaning it to me. Also thanks to Gary Hall for finding the unclassified pilot manual online. This provided massive amounts of information.
Other references include: "Janes all the World Aircraft."
Boeing Museum of Flight (A12 display and SR71 cockpit.)
"SR-71 Revealed" by Richard Graham.
"Flying the SR-71 Blackbird" by Richard Graham.
"SR-71 Blackbird in action" by Squadron/Signal Publications
Personal interviews with former pilots, RSO's and Crew Chiefs.
Testers:
Gary Hall
Robert Armstrong
Johan
Marv Thompson

IMPORTANT!!! USE AT YOUR OWN RISK! THIS AUTHOR WILL NOT ASSUME ANY RESPONSIBILITY FOR ANY FAILURE WHATSOEVER, IN HARDWARE or SOFTWARE.
- NO CLAIM IS MADE AS TO REAL-WORLD ACCURACY OR AUTHENTICITY although efery effort was made to get close with reasonable effort.
- ONLY ADD-ONS AND GAUGES MENTIONED IN THIS DOCUMENT WERE TESTED WITH THE MODEL. OTHER SOFTWARE MAY PRODUCE UNEXPECTED OR UNDOCUMENTED RESULTS. THE USER ASSUMES ALL RESPONSIBILITY FOR SOFTWARE (including panel and sounds) NOT INCLUDED IN THIS DISTRIBUTION.
- HIGHLY TECHNICAL AIRCRAFT WHICH REQUIRES STRICT PROCEDURES AND COMPLIANCE WITH SPECIFICATIONS.

Typical first time pilot errors include:
- Using a substitude panel. The model only flies correctly with the supplied panel properly installed.
- Using substitude cfg and air files. Only the files provided work properly and will not work in another model.
- Confusing KEAS with KIAS.
- FS Realism settings too low.
- Take off from the ground with full fuel.
- Improper fuel loading on the ground. ALL EIGHT tanks must be configured properly.
- Weather too warm or cold at cruise altitude.
- Descending from cruise at too-high rate or too slow.
- Inattention to engine and flight specifications and limitations.
- Trying to land at too-low pitch and angle of attack.
- Imcorrect panel switch settings.
- Incompatible gauge add-ons.
- Using panel Slave mode when you are not the guest in a shared multiplayer aircraft. - Unlimited Fuel Cheat will result in improper fuel balance.

Typical Flight Profile Summary:
Fuel is loaded using one of three standard loads based on mission requirements. Rarely (if ever) is full fuel load used. Take off full power on Afterburner with shallow climb while raising gear until 230 KIAS, then full climb. Sub-Mach cruise is Mach 0.9 and 28K ft. If air refueling, this is performed between 28K and 35K ft and Mach 0.8 - 0.85. Mach climb is performed after a "Dipsey Doodle" maneuver where after climbing to 34K ft @ Mach 0.95, shallow dive at full power to 390 KIAS, transitioning to shallow climb until reaching one of two scheduled climb speeds of 400 KEAS or 450 KEAS, where EAS hold is engaged. Climb continues at 3000-3500 ft/min decreasing above 60K ft until reaching Mach 3.0 where the AP/AT is transitioned from EAS hold to Mach hold. Climb continues at decreasing rates until crossing 425 KIAS where AT hold is transitioned to hold 390 - 408 KIAS for the remainder of the cruise while keeping EAS above 310. At speed near Mach 3.2, descent starts @ 325 miles from landing with EAS hold engaged to maintain 365 KEAS until terminal area procedures. Approach and landing speeds are determined by weight using 175 KIAS and 155 KIAS respectively for 10K lbs fuel and Angle of Attack approaching +10 degrees.
More specific information detailing these procedures along with relevant instrument indications will be found throughout this manual and in the aircraft kneepads.

How to set Mach Speed over Mach 3.00 in Flight Simulator

Features and images in this document may change without notice.
This model requires an experienced Flight Simulator enthusiast who might enjoy high altitude, high performance aircraft. The flight model is as realistic as my skill and FS2004/FSX will allow. All FS realism settings must be set to maximum for realistic flight. To prevent some extreme weather effects, "Weather Changes" Tab in the Options->Display should be set to slow which helps reduce the effects of extreme weather server data while using the simulation Jeppeson online weather.
The skill level required to fly the aircraft as it was meant to fly is considerable, even within the simplified Flight Simulator limitations.
I suggest new pilots work up to this aircraft by starting with FS2004/FSX training scenarios and up through faster two-engine jets like the Lear or FA-18. When comfortable with the FS interface, flight procedures, and high speed, multi-engine aircraft, you'll be ready to step up to the fastest piloted jet plane in the world.

Features:

  • BECKY real world training sortie with step by step instructions in text file: "BECKY_Training_tutorial.txt" provided in same directory as this manual along with FSX flight plan and ideal weather provided in FSX saved flight start location at Beale AFB (KBAB.)
  • FSX 3D sound. Of course, the pilot is snugly tucked inside a pressure suit and only hears comms and his air supply, so the sound is exaggerated for situational awareness.
  • Realistic after-burner (shift-F4) tied to throttle position as well as detent shut down.
  • Afterburner effect using smoke and flame effect triggered by AB enabled. FSX Acceleration Pack enables 10 AB stages above 80% throttle. Note: APack testing has been minimal. There may be issues with gear causing bouncing on the ground.
  • Nose and Spike thermal glow effect.
  • Drag Chute (/ spoiler key) is fully implimented.
  • Note: Model will not fly with drag chute activated which is prevented except when opening the canopy in the air which causes the chute to open representing severe drag.
  • The COL has been carefully calibrated to closely follow the trim table in the official SR71 pilot's manual when 450 EAS schedule is applied.
  • Engine Spike position is automatic above Mach 1.6 providing a performance boost. Below that speed, the spike can be positioned manually. Improper spike positioning can cause Un-Starts. Auto (spike knobs straight up) is the defautl position.
  • Fuel loading is simplified so all tanks can be loaded to the same percentage on the ground. Once loaded, an auto fuel maintenance program keeps the plane properly balanced.
  • Unstarts and compressor stalls are possible. They are not random events and may occur from rapid weather changes, steep banks, too slow, too rapid descent or pilot inattentiveness.
  • Fuel Dump Switch.
  • Oxygen and Pressurization System.
  • Special Master/Slave shared cockpit switch permits flying this model in FSX shared plane mode. By switching between master (for the host computer) and slave (for the guest computer) the gauge logic in the panel gauges will switch so the MASTER PANEL will control vital features. Without this switch, the two panels will conflict with each other because of time delays and latency. The "panel.cfg" file contains a special section which requires editing if a pilot wants to join a multiplayer shared session as a guest. Once the panel is edited and saved, the guest then joins the hosted session and after the plane is fully loaded in the multiplayer session, click the Master/Slave switch to the SLAVE position.
    The Host pilot panel will now control special features such as the possibility of unstarts, refueling, spike position, etc.
    When the host pilot transfers control to the guest pilot using the FSX command (shift-T) the guest pilot must also switch the Master/Slave so the multiplayer guest panel (who is now the controlling pilot) will take control of the special gauge logic.
    Each time control is transfered, the controlling pilot also switches the Master/Slave switch. The other pilots's switch will change automatically.
    To fly as a single pilot online or offline as non-shared, no editing of the panel file is necessary. Leave the switch in Master mode (default UP.)
    NOTE: After editing the panel.cfg file into the guest/slave mode, that panel switch will now default to the slave mode (down) each time the plane is loaded. This will be a problem if you are no longer joining a session as a guest or are flying single-seat. If you do not edit the cfg file back to the host/master mode default, you will have to remember to switch the panel Master/Slave switch manually to the Master (UP) mode or you will lose control of the aircraft.
    Multiplayer shared sessions will work best if the host computer is the master panel because of Internet latency. Also, the guest computer gets the weather from the host computer, so the guest panel does not react to weather changes as quickly as the host.

Weight (the balancing act)
You will read many references to weight and weather in provided documentation.
These two variables affect the performance of the model dramatically. Especially at high altitude 40K to 50K feet higher than typical airliners fly.
You cannot fly at maximum altitude, at max weight in very high or low air pressure where the temperature is excessively cold or warm. Stable flight is a careful balance of flight path planning, altitude, speed, COG and fuel load. Considering the aircraft has no flaps or spoilers, it has a 200+ knots air speed range of stability at Mach cruise.
The eight segments that make up the seven fuel tanks have been carefully placed to provide the required balance shift during a normal fight through natural attrition and tank switching which should not require pilot intervention except if the pilot loads the tanks incorrectly on the ground. In addition, like the Concorde, an automatic fuel pump provide additional fuel movment. Air refueling with the provided gauge will maintain this proper balance. A COG warning annunciator gauge and COG readout in the fuel and main panels will assist the pilot in monitoring the balance. Error should only occur in off-nominal fuel loading or flight conditions. Fuel Loading and maintenance is covered in depth later.
Warning: If the tanks are unbalanced left and right which can happen from extended engine out, automated CG errors would occur. For this reason, crossfeed is forced on.
Fuel Balance overview:
On the ground with all tanks set to the same percentage, the fuel is near the normal center of balance for take off (nominally ~20-22%.) If it's too high, rapid rotation causing tail strike may result. Attrition causes COG to shift slowly rearward to a mximum of +25% while over Mach 2.9 cruise and total aircraft weight under 120K lbs. The Annunciator will display "FUEL LOAD" when on the ground and less than 45K lbs fuel is loaded and the Main (number three) tanks are too low.
Near the end of the flight when the fuel load is low, the weight has shifted forward to +21.5% for 10K lbs fuel landing.
An Annunciator "Hi CG" will display if the CG is more than 22.0 under Mach 0.9.
There are forward and rear COG limits of +17 to + 25 in addition to more restrictive limits during certain modes of flight.
In typical flights, weight shift forward of landing COG will not occur.
The annunciator will provide yellow warnings when COG is only slightly out of limits (plane is still flyable) and red when maximum limits are exceded. A short period of yellow warning during refueling processes or near final approach is normal. If you are flying at high altitude and fast under 8K lbs fuel, you might have trouble getting down to land in time without refueling. Typical descent fuel weight is between 16K - 18K lbs and CG aft of 21.5%. Optimum landing CG is between 21 and 22 percent. OVER-LOADING THE FUEL CAUSES A LETHARGIC CLIMB, SLUGGISH HANDLING AND DIFFICULT DESCENTS SO ATTENTION TO FUEL LOADING FOR THE FLIGHT PLAN WILL INCREASE THE PERFORMANCE, RANGE, AND FLIGHT SATISFACTION.

The Panel is a collection of gauges from other planes which fit the general theme of grey-black high performance aircraft. Many custom gauges unique to the SR-71 were constructed. My emphasis has been on the accuracy and flyability of the flight model. As my elementary gauge making skill improves, I'll replace more of the gauges and add more realistic ones. I invite gauge artists who enjoy high performance aircraft to participate in creating a freeware panel that does justice to this amazing aircraft.
GAUGE BUGS: The "Sandel" HSI supplied with this panel has an error in the "NAV" button which when set to "GPS" causes the autopilot heading bug settings to jump by increments of 10. I suggest not using this mode. In this release, the Autopilot panel has been re-designed. The heading set bug error is now gone.

SR71-FS2004/FSX Weather environment:
LAYERS (51K)
This graphic from NASA illustrates the earth's atmospheric layers. The SR-71 cruises at altitudes between 21 to 27 Km riding the Tropopause. The air temperature reaches a low point near this altitude and warms both descending and climbing. In Flight Simulator 2004 (FS9) the built-in Jeppeson weather simulator includes data only up to around 55K ft in FSX (about 25K lower than the SR cruises.) Above this limit, the simulation creates steadily warmer temperatures (which mimics the chart above.) Unfortunately, the coldest the sim sets at 55K ft as the top layer is 10 to 15C WARMER than is normal for cruise in the SR. The sim will not create colder temperature than the top layer in the weather data sent to the sim.
Jeppeson emulation in FSX is better than FS9, but still has extreme jumps caused by station proximity interpolation data errors.
When using Jeppeson (or similar emulation like Vatsim) by the time you reach SR cruise altitudes, the air can be as warm as if you were flying at 30K ft. This makes high speed flight impossible without over-heating. What makes high speed flight possible is the thin-cold air at the extreme altitudes of air breathing engines. Another problem with Jeppeson weather is beyond continental and coastal station data, the lack of weather stations causes the sim to load a default profile until new station data arrives. This default data is a fixed pressure and temperature of -58 deg and 29.92 OR whatever user-created or weather profile was loaded with a saved aircraft flight. This can cause extreme behavior as the sim transitions in and out of this default data when flying in remote areas and over water. The SR-71 spends most of its time in remote areas and over water so this is why a more accurate and comprehensive weather simulator is needed.
I worked with the designers of Active Sky(AS) to encourage them to emulate the Tropopause conditions for high performance aircraft like the SR71 and Concorde. This flight model was specifically designed to operate with Active Sky 6.5 and FS2004 until this sim was ported over to FSX, and is now optimized to work with AS2012 SP1.

ASE and the intial release of AS2012 had excessive cold temperature above 60K ft causing severe flight problems with Concord and SR-71. As of this manual update, ActiveSky 2012 SP1 has had a major over-haul of high altitude optimizing pressure, temperature and winds.
The setting combination of "DWC" and "DWC with Local Writes" and "Prevent Cloud Redraws with DWC" will provide the smoothest high altitude weather with minimal cloud popping.

When ANY program sets the temperature of the highest layer, FS will gradually produce warmer temperatures above the highest defined layer.
In FSX, this flight model has been made as tolerant of the built-in Jeppeson download weather as possible. Most of the time, flights work out OK but there are areas of the world where very bad weather emulation is almost guarenteed. In my experience this includes:
Newfoundland Canada, Coastal BC Canada, Mid Atlantic between Canada and England, Soutch Eastern England and the US Mountain states.
NOTE: When using Jeppson Weather, make sure The Options->Display->Weather Tab->"Rate at which weather changes..." is set to low which provides some smoothing of weather transitions at the cost of some accuracy. In FS, better the weather transitions slowly than accurately given the extreme diversity of weather station data.

FSrealWX Lite has been briefly tested using this model and so far appears to be superior to the default Jeppeson in many ways, particularly high altitude temperatures.
These are the settings I use:

  
General:
 Vatsim
 Update Int: 10
 Downloads: Upper air, additional, TAF
Weather:
 Position NM = 300
 WX Stations only ahead
 Set Global
 Dynamic = 1 (this sets the dynamic slider in FSX to none so no internal morphing)
 Vis Limit = 190
 Turbulence in cumulous
 Max Wind Shift = 15
DWC and Interface:
 Enable DWC
 Degrees/sec = 1, Knots/sec = 1
 FSUIPC and SIMCONNECT
 
I have FSUIPC wind smoothing off due to current bug over 52K ft, and pressure smoothing on. The DWC mode creates extreme cloud changes because a single weather environment is being written to the whole world each update. At times, pressure changes are too frequent and large at cruise.

As downloaded data creates weather around the world, it will set the top layer to different altitudes and temperatures. Because of this, you will never have the same flight conditions twice. Sometimes you will get weather warmer or colder than the operating limits. As in the real world, pilots flying the Concorde and SR71 had to ride a range of altitudes and speeds to continually optimize the conditions for maximum range. I call it "Threading the Amospheric Needle." In the sim, the most important indicators are the Compressor Inlet Temperature (EGT) Air Speed Indicator (ASI) and Fuel Flow (FFI.) To prevent structural damage or stalls, the aircraft has to be flown between a 140 knot speed band (370 - 510 KIAS.) To prevent engine failure, the combination of Compressor Inlet Temperature (CIT) and EGT must be kept within their limits which are strongly influenced by the Static Air Temperature (SAT) Engine RPM and air speed.

The tools you will use to juggle the temperature and structural limits are altitude and air speed.
By keeping the IAS setting so the ASI is kept as close to between 400 to 410 KIAS as possible you will fly right in the middle of the structural limit range between failure and stall.
By adjusting the altitude of your flight between 72K and 82K feet to keep the CIT below 427C, you manage the temperature of the air to prevent engine damage. The last of the three tools of the flight management is Fuel Flow (FFI.) By keeping the fuel rate under 20K lbs/hr per engine at cruise, you will get the maximum range the flight model is designed for.

As you read further into this guide, you will see many references to speed and altitude limits. I hope this summary will give you the background to understand why these limits are there and to assure you they are indeed real world. Pilots had to plan their flight and fly their plan to cooperate with these limits. Unlike airliner flights where you set a altitude and Mach and keep them for the whole cruise, the SR71 "Habu" pilot can rarely enjoy that kind of leisure. Most flights will be relatively calm and uneventful. Some will have you changing speeds and altitude frequently to stay ahead of the changing weather situation. Configuration for the most trouble-free flight is covered in the flight prep portion of this document.

The following graphic from NASA illustrates the effect of altitude and pressure:
Alt_Press (28K)
As you fly, FS is constantly comparing the distance between the plane's position to the nearest weather stations the weather program has loaded into memory from online weather servers.
FS uses the calculated closest station pressure for the current pressure. In remote areas of the world, these stations may be hundreds or thousands of miles apart with vastly different weather. This strategy can cause large pressure jumps from station-to-station as you get closer to a new station and leave another behind. You may also leave a relatively sparse station area to a dense area where a new station becomes "closer" every few seconds. This character is complicated by the SR's great speed traveling around 1/2 mile per second. Active Sky adopted the unique ability to create temporary "virtual" stations in remote areas between real station data. In earlier versions this helped solve another problem the FS weather simulation causes:
When there isn't enough station data to provide a local weather environment within apprx 60 miles, FS drops all loaded data and sets a local default condition of pressure 29.92 and -58 degrees C at 45K ft. When this happens, if the weather you were flying in up to that point was vastly different, you may get a very large altitude transition and engine power spike (because the engines are sensitive to temperature.) The virtual stations AS attempts to create helps fill in the gaps between stations, but errors in station data still causes the FS default conditions to load once in a while. When the aircraft is flying in pressure changes representing hundreds of feet in an instant, the speed and lift of the aircraft can change drastically. Needless to say, this digital weather emulation leaves a lot to be desired compared to the real world. For this reason, the Habu pilot has to be attentive. You can be assured, it is possible to have hundreds of hours of trouble-free flight. I hope I've made you aware though it isn't always that way. Even in the real world, there were some damaged and crashed SR71 planes.

TAKEOFF (211K)
sr_ir
2D (282K)
VIRTUAL (178K)

The real plane:
ASM_3D1 (58K)

Mach 3.2 Flight Reference Panel Screenshot:
View Image: Mach 3.2.jpg
When flying at Mach 3.2, 80K ft with a take off fuel weight of 66K lbs, your main 2D panel and the circled gauges should look very close to the above linked image. If not, there is something wrong with fuel loading, flight procedure, installation, gauge or add-on compatibility, simulation options, or simulation version compatibility.

Special Gauges:
This section describes several non-standard FS custom gauges which reflect true real world limitations of the aircraft. As exceptional as it is, it's not a space shuttle. Real world pilots had limitations placed on what they could do. In addition, there were physical limitations to the airframe and engines.
These are discussed again later in this document within relevant sections.

AutoPilot Master Switch: To the left of the engine gauges is a rotary knob indicating the master mode of the Autopilot.
AP_mode From top to bottom the settings are:
OFF: If the AP master switch is on, this does not turn the AP Master switch off, but it will disable any AP modes currently on.
HDG: Enables Heading mode
NAV: Enables VOR/GPS Mode
ILS: Enables ILS Mode
BC: Enables ILS Backcourse Mode

When you use this knob to change the AP, a click on the label for the mode you want enables that mode and the knob rotates to point to it. Another click on the same spot disables that mode, which functions the same as the OFF position.

If BC mode is enabled, then clicked again to disable it, the switch will move to the ILS mode to indicate ILS is still active. Click again on ILS or OFF mode to disable the ILS after selecting BC.

This gauges does not interfere with the AP Window or any mode set there or using key commands. Doing so, the knob will simply echo your choices.

REFUEL: The top left center of the main panel features a gauge with three functional switches.
REFUEL_D (2K) 1) Fuel Transfer Switch (Top Center- shown off in the center position)
REFUEL_R (2K) 2) READY/DISC: Ready Disconnect Switch (shown enabled.)
The Ready switch must first be activated which opens the fuel door and activates the transfer electronics.
Notice also when the Ready switch is enabled, two rows of numbers which were previously hidden also display.
REFUEL_O (3K) When the Transfer switch is enabled (shown UP in the ON position) fuel will begin flowing as shown in the top row of numbers as pounds. The bottom row of numbers is the current TARGET REQUESTED amount of transfer fuel in pounds. The requested (bottom) number changes as the engines deplete the tank and the tank fills. Because FS2004/FSX Deluxe ADD_FUEL function always transfers fuel in 25% of unused capacity increments, your fuel tank indicators will not show the added fuel until the top number fuel flow indicator matches the bottom number requested fuel. The request estimate is based on FS's tank fill percentage calculation. After each anount is transferred, the request number will re-estimate the amount required for the next update of fuel. As refueling continues, when next the top number and the bottom number match, the fuel tanks will update again.
The rate at which the top number increments (which controls how fast the request number is matched) is at the realistic rate of 6,000 lbs/hour. Roughly nine and one half minutes are required to fill from 20K lbs to 80K+ lbs. When full capacity is reached, the transfer switch will shut off automatically. As long as the RDY switch remains enabled, even though the transfer switch is off, the current request amounts and transferred amounts will continue to display. This allows you to halt the transfer between updates, check the amount of fuel which is being requested against how much you want, and continue the transfer where you left off. You can also see the total amount transferred for record keeping. When the RDY switch is disabled, the number display will clear and show again as zeros when next activated. If the RDY switch is allowed to turn itself off when refueling parameters are exceeded, reactivating the switch will display the last numbers shown. Cycle the RDY button to clear the numbers to zeros. Warning: If the RDY button is left on (lit bright) the pressurization system detects this as refueling stress and will increase the Oxygen usage.
Constraints: Parameters necessary to operate the switches are very forgiving at this time:
270 - 350 KIAS
24K ft - 36K ft
Both engine fuel valves must be enabled (engines are operating normally.)
When refueling constrainsts are exceeded, the RDY switch will disable.
REFUEL_T (6K)
High fuel loads at low speeds cause the engines to be near maximum military power during the last portion of the transfer. It's typical for Habu pilots to enable the AB on one engine and use differential engines settings to balance the yaw, thus providing more power headroom during refueling.
KEAS Speed Hold Switch (center red) when enabled will capture current EAS and try to hold it until disabled.
To use EAS Hold while in IAS mode: Click the KEAS button (will change to brighter color) while the KEAS display in the Triple gauge displays the desired speed. The speed will be captured in memory and the AP IAS bug will adjust to hold that speed within a few knots. Note: The KEAS hold feature is slow to respond to rapid speed changes.
To use while in Mach mode: Disable Mach hold and click the KEAS button when Triple KEAS display matches your desired hold speed. Button will change to a bright color. You can help the hold through rough weather by adjusting the IAS speed bug manaully while hold is still engaged.
To Disable: Click the KEAS Hold button again (will darken) or click the AP Mach hold button. IAS mode will disengage. This feature is also available in the AP panel.
Steer On is a lamp which brightens when the nose gear makes contact with the ground and the gear is undamaged.
There is no switch or user action associated with this feature.

CIT/EGT:
CIT<- CIT at normal cruise temperatures
The Compressor Inlet Temperature was not permitted to exceeded 427 degrees Celsius or 125C below mach 2 (with the IGV light on.) If the 427C limit is exceeded for 30 continuous minutes or more an engine will fail.
When failed, the engine cannot be restarted. CIT at 450C or above will fail immediately.
Note: The rapid loss of airspeed and resultant cooling will likely preserve the other engine.
The display includes a red band above 427C and a red mark at 125C which is the limit below mach 2 with inlet guide vanes open.

ENGSTACK (39K)

The Exhaust Gas Temperature displayed as digits above "EGT C" has a built-in electronic "trimming" system to lean the fuel to air mixture and reduce over-heating. If the EGT reaches 860C or more, when enabled, the de-rich system will engage which shuts off the AT IAS hold function and sets the throttles to 88%. This protection mode is usually the result of highly unusual data from an external weather system and in this system functions as an emergency weather data safeguagrd. The EGT text displays yellow "LIMIT" when the EGT reaches 830 C (continuous operating limit) orange and red "hot" indicators for 845C and 900C. EGT below 400 will indicate "COLD.".
Note: If the derich system is not engaged, high EG temperatures will result when flown in warmer than normal air temperatures. It is a good idea to always engage Derich when flying faster than Mach 3. At this time, there are no failures associated with this gauge.

CIP:
CIP
Compressor Inlet Pressure under the CIT gauge displays engine inlet pressure Pounds Per Square Inch Atmosphere (PSIA) and has three needles: Left and Right engine "Actual" readings and a striped "Expected" barber pole indication. Unless there is an engine fault, the two actual needles are usually perfectly overlapped. The Expected Barber Pole is the theoretical performance when under normal climb, cruise and descent using the three documented schedules (400 EAS climb, 450 EAS climb, and 365 EAS descent) and Cruise. Normally the Barber Pole is hidden behind the actual needles unless the aircraft is being operated outside expected parameters. It's normal for the expected and actual needles to leapfrog each other for a few seconds once in a while. Extended periods where the needles are separated by a needle width or more indicates off-nominal performance caused by flying significantly off schedule. When this happens, the annumciator will display "INLET" and the Master Warning lamp will light. If the expected speed is below the actual needles, the plane is flying slower than expected for the altitude and pressure. Acceleration and/or descent may be required. If the barber pole is ahead, then the plane is too fast or low. You should slow and/or climb. The CIP gauge is used as an early indication of an impending engine unstart when flying above Mach 1.5. Below Mach 1.5, indications are not critical. While on the ground, the barber pole indicates the expected take off profile, not the current idle or taxi engine condition. Normal Mach 3+ cruise will produce around 15 - 16 PSI. A red flag at the bottom of the gauge indicates invalid gauge operation due to error in the data (usually engine failure, flight performance outside published data or near landing.) Typical behavior shows atmospheric pressure with engines stopped. Profile:
In flight, pressure peaks near 15 shortly after take off, then drops to lowest reading near Mach 1.6 (around 6.2 using 400 EAS climb, 9.1 using 450 EAS) then increases with speed above Mach 1.6.
Note: At this time, there are no performance hits associated with this gauge. In the future it will be tied to the unstart logic as it was necessary to perform the calculations this gauge represents so the bypass doors can eventually be emulated. The gauge is introduced at this time so pilots can get used to how the gauge looks in normal flight prior to introducing a new fault tree.

The engine stack gauges from top to bottom are:
  • N2 Percent with digital RPM (changes from while to yellow or red near rated upper and lower limits)
  • EGT readout
  • Temperature range text (COLD, LIMIT, HOT)
  • DERICH text (when activated)
  • Nozzle Position
  • IGV lights (yellow when open below Mach 2: See Inlet Temperature Gauge above)
  • Fuel Flow (010 = 10K lbs/hr on digital display) Full Clockwise = 20K lbs on needle
  • Oil Pressure
Note: The exhaust nozzle gauge is displayed realistically based on throttle and Mach3+ speed rather than the position shown on the 3D model which is tied to the throttle position only.

Annunciator:
ANNUN (24K) System state and failure warning system. Many of the warnings mimic actual plane warning lights although for space and practical purposes some lights are not included. Some warnings will also activate the Master Warning Light on the upper right of the main panel next to the Shaker light.
The systems and warnings are as follows:

Warning

Description

OIL PSI

Psi drops below 25

OIL
TEMP

Below 15C or above 177C

FUEL
PRESS

Below 7 Psi

OIL
LEVEL

Below 15%

HYD
PRESS

Below 2000 psi or above 3500 psi

HYD
LEVEL

Below 25%

BUS
VOLTS

Below 22 Volts

GEN
OFF

Generator Switch Off

FAIL

Engine Failed (cannot restart)

ICE

INLET

ICE will display if ice is forming on Pitot Tube or aircraft structure. INLET will display if the CIT is too high or the CIP error is large above Mach 1.5.

GEAR
GEAR TR
or
GEAR LIMIT or
GEAR DAMAGED

PITOT H

GEAR will display when throttle is low and aircraft below 3000ft. GEAR TR when the gear is in transit.
Pitot H indicates PH switch is off. GEAR DAMAGED while extended above speed limit.*

SPEED HI and STALL Warnings

FUEL LOW

SPEED HI and STALL WARN in yellow and red to indicate various levels.
Fuel Low indicates tank 2 is below 5400 lbs AND tank4 is below 4050 lbs

COG Warnings

EMER BAT/APU On

COG warning system calculates speed and weight under various conditions and warns when COG is out of config with yellow (minor) and red (beyond limits) alerts. FUEL LOAD while on the ground indicates the fuel quantity or distibution is wrong for take off. Green text will display above Mach 3 and >= 30K lbs fuel suggesting ideal CG ranges based on weight.
"EMER BAT" indicates battery is being drained (low gen output vs use.) or APU Power Unit is off.

TRIM

CANOPY/CABIN PSI

Pitch Trim is too nose down (< -1.5) caused by too fast, too low or too aft COG. Canopy Open/Too rapid descent Cabin Pressure or Cabin Dump Open.

LIMITER

A-SKID
TIRE

Surface Limiter (Yaw Damper Off). Anti-Skid Disabled. TIRE Yellow=Cool Down Required. TIRE Red=Tire Temp Limit

* Gear damage may include:

  • Primary Gear Lever Fail
  • Nose Wheel Steering Fail
  • Breaks Fail

Drag Chute:
DSSTATES (13K) The drag chute gauge has three states: not deployed, auto-armed (shift-/) and deployed (/.) Full chute deploy takes apprx 5 seconds. The drag chute cannot be deployed while in the air. If you arm the chute on the ground, the ground contact sensor will deploy the chute. You can also arm the chute while in the air. When there is ground contact of the main wheels AND the throttle is lowered to idle, the chute will deploy. Standard procedure requires the chute not be deployed in cross wind until front gear makes contact.
Note: When retracting or "jettisoning" the chute, it takes 5 seconds for the lever to return to its normal position. The image at the upper right displays these three states. Notice the "normal" un-deployed state has a black center. The armed for auto deployment state shows a bright yellow center but otherwise looks like the un-deployed state. The deployed state has a bright green center and is extended toward the pilot on a red shaft. The gauge cannot be activated by mouse at this time. New Feature as of July 2012: When the canopy is opened in the air, the chute will deploy representing severe drag. Close the canopy to return to normal flight condition with chute retracted. Flight is near impossible in this condition and there is loss of cabin pressure.
Note: The 3D panel lever does not display the armining state.
The chute has the following restrictions:
1) Will not auto deploy on the ground if the throttles are not idle.
3) 5 seconds are required after deploy for full drag effect and animation.
4) Landing weight has to be under 38K lbs fuel.
5) Landing speed has to be under 210 knots indicated.
6) Pilot cannot deploy chute in the air.

TEB:
Below the engine throttles are two (Triethylborane) counters, one for each engine. The counters are maintained separately for each engine. Each time an engine is successfully started or the AB is enabled on a fully operating engine, the TEB count for the cycled engine will lower by one. You start out with 16 "shots" of TEB. When the count reaches zero, the affected engine cannot again be restarted or its AB enabled (if off.) The TEB count is only lowered if the engine start is successful or the throttle position is 80% or more for engaging afterburners. An engine which is fully functioning will remain working if the counter reaches zero until another failure occurs. If the fault is an unstart, the engine will not start. If the engine is running but AB is turned off, the AB cannot be reactivated.

Spike:SPIKE (33K) The Spike position gauge is a critical key to the ability of the J-58 to obtain Mach 2 and 3+. Together with front and rear bypass doors, they prevent supersonic air from entering the compressor and stalling the engine. At this time, the door operation is not yet implemented. In the real SR, the spike is maintained by a computer which is simulated in this model above Mach 1.6. The spike indicator will display positions between 0 inches (moved fully out and away from the engine intake) to +26 inches (AFT) or fully retracted into the engine.
You can move the spike manually while on the ground to confirm its operation, but having it positioned in other than zero while in flight and below mach 1.6 will cause an unstart.

Spike_auto <-- Spike Mode rotary knob shown in default "Auto Mode" (knobs pointing UP)

Spike_man -->
Spike mode shown in the manual (knobs right) mode.

Manual spike operation requires placing "SPIKE" rotary knobs in the right (non-auto) position. To toggle the auto-manual spike mode, click on the center of the left knob which changes the mode for BOTH engines.
New Pilots should leave the mode in auto.

The default startup switch position is up (auto) which is computer-controlled normal mode.
In manual mode, Adjust the spike position using the flaps keys (F5-F8.)
Beginning at Mach 1.6 and faster, various kinds of failures related to incorrect spike position, high AOA, too-low descent speeds, and high bank angles can cause compressor stalls and unstarts. Please consult the specifications section to order to avoid these problems. USSTATES (2K) Unstarts were a well known problem on the SR-71 and happened most frequently during descents. In this simulation, you need to be more attentive to descents than other flight profiles.
Note: Habu pilots refer to various modes of flight where specific procedures or aircraft systems settings and operation are required as "schedules." You will read references to this term elsewhere in the manual.

What's an Unstart?
The "Unstart" term comes from the idea that close to Mach 1.6 and above, supersonic air flow inside part of the inlet has "started" and a shock wave builds behind the spike lowering the intake pressure and diverting excess pressure out through bypass doors and vents in the nacel. The spike and bypass doors follow "scheduled" position changes related to mach speed, pressure, and temperature to preserve the position of the shock and bypass excessive pressure out of the nacel through grills in front of the engine. Loss of the shock wave position control allows the shock to enter the engine and causes similar symptoms as a compressor stall.
When the engine unstarts or stalls above Mach 1.6, the engine RPM will drop suddenly, there will be an extreme yaw moment in the direction of the failed engine, the afterburner will go out, and aircraft speed will drop rapidly while the Autothrottle tries to recover speed with full RPM on the remaining engine. Loss of speed also causes the AP to pitch up trying to maintain altitude which further complicates the impending airodynamic stall. The computer will move the spike position forward to re-capture the shock wave for auto-restarting the engine. Both spikes ALWAYS move together. The computer will keep the spike forward until the failed engine condition is corrected. When the engine RPM drops enough to restart, the failed engine will restart itself as long as all dynamic conditions which caused the failure have been corrected. While above mach 3, speed will need to be recovered to above 350 KEAS which usually requires a rapid dive and full power on the remaining engine.
If you react too slowly, you'll have to restart the engine yourself with the starter switch on the panel or Contrl-E key combo. Each successful engine restart will cost you two hits of TEB (one for the start, another for the AB) so it's good to be sure all the conditions allow for a successful manual start or you will waste TEB.
Restarts are normally performed at Full Military Throttle and above 350 KEAS to prevent another compressor stall.
The Unstart light for the failed engine side should ignite for an unstart, but may not always for a compressor stall. Several engine annunciator lights displaying are a further indication you have an unspooling engine (as well as all the engine gauges indicating low.)

Note: Compressor stalls are also simulated which can occur when sub mach. If the pitch is too high for the flight profile, or the mach descent is not maintained above 350 KEAS and/or the RPM drops below 6100 an engine will suddenly lose power and drop to an idle indication. The Unstart lights may not come on. The restart switches may try and fail to ignite the engine. When this happens, level out or start a rapid descent (-4500 FPM or more). The failed engine should ignite once speed is restored above 350 KEAS. Sometimes a manual restart is necessary.

ABThrottle:
This gauge is an enhancement to the main panel throttle. The SR71 has a combined throttle AB control (like most reheat jets.) To activate the AB, the throttle is moved to a hardware stop, then the handle is pulled out-away from the base on a spring and the throttle lifted over the stop into the minimum AB setting. ABSTATES (15K) Current Implementation: While on the ground the throttle will not permit movement past 80% (full military power.) To increase beyond 80% you have to engage the AB (shift-F4 in FSX Deluxe) which simulates lifting the throttle over the stop. Acceleration Pack may have a different behavior where an 80%+ setting activates the AB which can then be advanced further. Once the AB is engaged, the throttle can be moved at will. If you reduce the throttle below 80%, the AB will disengage automatically. In flight, the AB will also disengage below 80% and when operated manually, requiring AB engaged to advance belond 80% again. The Autothrottle does not have this limitation and will advance the throttle beyond 80% without the AB (on FS Deluxe) but available power is severly limited.

The gauge also provides a digital readout of the throttle percent setting. I added this feature for testing other code I was working on and grew to depend on the added position visibility it provided. I decided to make it permanent. Note: The real plane has throttle/engine performance which differs from FS in an important way:
The real plane operates at near max RPM through climb and cruise. What changes primarily is the fuel sent to the afterburner. In FS, engine power from the AB is not independent of RPM changes. For that reason exact RPM for all modes of flight are not strictly simulated.

This gauge also provides AB off/on and TO/GA indication. AB ON is indicated by changing the throttle percent number from green for "normal" military power to white for Afterburner. The image on the right shows these two states with full military power on the left and 85% with AB engaged on the right. Also shown are the two TEB counters at the bottom.
On the left side just under the throttle percentage readout for engine 1 is an engine selection readout. The purpose is to help confirm you have the correct engine selected for operation when selected individually. Shown in the graphic is both engine 1 and 2 is selected so the digits "12" are shown. When only one engine is selected, the display will show a 1 or a 2 only.
Take Off/Go Round power can be activated by Shift-Control-G or clicking on the Throttle Select numbers. When activated, the throttle selection numbers will change from green to orange. In FSX, the display will be blank in TOGA mode.
Reducing throttle below idle will shut off the engine (into the red or negative numbers on the throttle position display.) Restart requires moving throttle lever back to idle position (green) or above (F1 key.) Note: The throttles can only be moved to the detent engine shut-off position when stopped on the ground.

TRIM:
Three gauges show the degrees of Pitch, Yaw, and Roll trim movement of the aircraft components. Use these before flight to make sure the aircraft is configured for controlled flight. Use the keys: Control-numpad 7 and 1 for Pitch, Control-numpad 0 and Enter for Yaw, and Control cursor left and right for Roll. Small digital numbers also assist in displaying small movements. For take off, all three gauges should indicate zero. See specifications section for Pitch/COG limitations.
TRIM (15K)

DERICH (5K) The DERICH switch permits operation of the derich feature which reduces engine power when the EGT exceeds 860C. When the switch is in the default down position, the derich feature is disabled. In addition to the emergency throttle set-back while exceeding 860C, the derich function will also reduce the rate at which the EGT increases when it exceeds 805 degrees. It's usually a good idea to have this switch enabled above Mach 3.0 to further protect the engines from over-heat faults during hot take-offs or extreme weather changes at cruise.

A-SKID
Anti-Skid switch limits the ground braking strength by pulsing the toe brakes while the ground speed is above 12 knots during ground roll. The parking brake is disabled until at or below 12 knots. Steady "toe brake" pressure is required to activate the function when the switch is on. Anti-Skid ON is normal configuration and the Annunciator will indicate "A-SKID" if it is off. When OFF, excessive braking and heating will result. When ON the same annunciator position doubles as tire temp high indicators. See section below "Tire Heat" for details.

As you all well know, faults of any kind are not a normal part of FS simulations. The built-in random failure system is so unlikely and unrealistic no one wants to use it. Alternatively, the faults built into these gauges take some getting used to, but are an attempt to help wannabe "Habus" appreciate the skill and technical complexity associated with this unique aircraft. Although Airliner pilots are known to sleep at the stick from boredom, Habus could not! Go to sleep in this aircraft and you'll find yourself in a reset in short order. These faults are not random. The pilot has to fail to react to out-of-limit flight parameters for them to happen.
In a normal flight (correct altitude and speed for the temperature and decent rates) and under AP Control you will not have any faults.

Master Warning Light
In addition to the Annunciator Panel, to the right of the Attitude Indicator and below the Stick Shaker Light is the Master Warning Light and clear. The most important alerts from the Annunciator will also light the Master Warning. These include:

  • Battery Discharging
  • Fuel Low
  • Eng Low RPM
  • High COG
  • Engine Failed
  • Canopy Open in Flight
  • Low Cabin Pressure
  • Low Oxygen Supply (< 2%)
  • Cabin Pressure Dump Open
  • Near Overspeed
  • High CIT
  • Large CIP Error above Mach 1.5
  • High EGT (Hot or higher)
  • Gear Up landing
  • Gear Down in flight Above 320 Knots
  • Tires Hot (above 100C)
  • Near Stall over Mach 1.5
  • RPM drops near minimum above M 1.5
  • Ice Forming on Pitot Tube or Structure
Battery power is required for indication. Click on the Warning light to disable all warnings for this lamp. No more warnings will indicate until switch is clicked again although Annunciator Panel remains functional. See Qxygen stress factors below which relate to many of these same events. To check if you have disabled the Warning Light, briefly switch off both generators. If the light does not illuminate, it's disabled.
Since Engine failure and Gear damage are unrecoverable, the Master Warning does not light for these failures. If the Primary Gear lever does not operate, try the backup (Control-G.) This does not repair the gear.

Altimeter Pressure Trend
Although not a feature of the real SR-71, it's provided to help the pilot navigate the digital and often quirky world of FS weather.
On the left side of the main panel altimeter is a small digital display which shows one of three characters as a pressure trend:
= indicates there has been no atmospheric pressure change in the last 2.5 seconds.
+ indicates the atmospheric pressure has increased in the last 2.5 seconds.
- indicates the atmospheric pressure has dropped in the last 2.5 seconds.
In addition, the letters "H" or "L" will appear for high and low pressure indication:
LL indicates atmospheric pressure is below 1000.0 mb.
L indicates atmospheric pressure is betweem 1000.0 and 1109.82 mb.
No Letter indicates average atmospheric pressure.
H indicates atmospheric pressure is between 1016.59 and 1025.0 mb.
HH indicates atmospheric pressure is higher than 1025.0 mb.
Example:
=
Flying within average normal pressure (1009.8 - 1016.6 mb) with no recent change.
-L
Flying in low pressure which is dropping below 1009.82 mb.

Rapid cycles through these symbols means the pressure changes are very small.
Although there is no equivalent on the real plane, this feature greatly assists the pilot flying in online weather. If the pressure trend has been up or down for an extended period (30 seconds or more) during (L) indication, the pilot may be encouraged to increase speed and/or decrease altitude to forestall any surprises building up affecting the lift of the plane should the trend continue. Sudden pressure drops affect the aircraft as temprary increases in air speed. After the Autothrottle compensates, the result is reduced power margin as if the plane were flying much higher.
If pressure then increases suddenly, the result is not enough power to compensate, forcing a descent to regain air speed or recover from unstart.
In low pressure (L) the pilot should avoid altitudes above 78K ft and may have to fly as low as 74K ft in "LL" indication depending on the temperature. In my experience, although high (H) pressure can mean you may fly in the range above 80K ft, these high pressure ridges are often short lived in Jeppeson online. In Active Sky 2012 SP2 or later, the far superior weather simulation will require little (if any) pilot intervention.
Better to be safe than sorry. In hundreds of hours in Jeppeson weather flying around the world up to 11 hours at a time, stable flights can be found in the altitude range between 74 - 80 thousand feet.

Tire Heat:
Hidden gauge "tire_temp" measures weight, speed on the ground, braking intensity and friction temperature to calculate the effects of taxi and breaking. If the special gauge panel "Flight Data" and its associated gauge "Data" is enabled in the panel configuration, a constant readout of the main tire temperatures are available.
A new feature added to the annunciator tied to the Anti-Skid function above is when Anti-Skid is enabled the annunciator will report when surface temperature, braking temperature, and speed combine to heat the brakes and tires above safe levels. Yellow "TIRE" indication requires a parked hold before take off roll. Red "TIRE" indicates temperatures are too high on one or both tires for high speed roll (over 100C.) Wait for yellow TIRE inidcation to go out before starting take off roll.
If Anti-Skid is disabled, these temperature indications are disabled. Above 50K ft the tire warnings are suppressed. The Anti-Skid switch can toggle between display temp warnings or anti-skid off warning in the annunciator. Anti-skid should always be on for landing/roll or excessive brake pressure and heating will result.
Typically, when stopped and the yellow "TIRE" warning is illuminated, ~60 seconds is required to cool from 90C to below 40C for a safe take off when the surface temperature is near 95 deg F on the ground.
Surface wind and cold air help cool the tires.

Oxygen System:
Shift-4 opens up the Fuel and Oxygen panel. There are three gauges and three switches associated with Oxygen and Pressurization.
The upper left "OXY SYS" switch controls which oxygen tanks are being used. The default on startup is "PRI" (UP) which uses the primary Oxygen tanks to pressurize cockpit and suits. Primary consists of 2ea, 10 liter liquid tanks providing 20 hours under normal usage. STB (DOWN) is the standby 10 liter tank providing an additional 10 hours for two crew at normal usage rate. FUEL_PNL The "PRESS DUMP" switch at the bottom defaults to off. When ON (UP) the oxygen system is switched off. The suits will use internal oxygen and the Annunciator panel will display "Cabin Psi" until the switch is changed to off. To the right of the PRI/STB switch is the OXYGEN PRESS gauge which always displays the pressure in both systems in pounds. These indicators will display within the upper half until the relevant oxygen quantity is nearly depleated. When depleated, pressurization will fail and Master Warning light will stay on unless forced off or supply is switched to a pressurized tank.
The lower "Liquid Qxygen" displays quantity in the system which is currently in use. To save space, since the Primary tanks 1 and 2 are used together, the same ten liter indicator is used to display both 10 liter Primary tanks.
To prevent unwanted oxygen system usage while on the ground, open the canopy (shift-e) which will automatically position the Cabin Press Dump switch to the ON (UP) position and shut off the oxygen system. The Annunciator panel will display the warning "CANOPY".
On the upper right of the panel, the "PRESS SEL" switch selects between Normal 26K ft (default UP) and 10K ft cabin pressure. The gauge to the left of the switch indicates the current pressurization level. Below the pressure gauge is a digital readout of the current pressure selection. When switching between the two altitudes, about 3.5 minutes is required to fully transition to the new level. NOTE: Using the 10K ft pressure causes a large increase in oxygen use rate.
When ready to start engines, close the canopy (shift-e) and click the cabin dump switch to the off (DOWN) position. Careful not to click the Fuel Dump switch by mistake!
The Annunciator "CABIN PSI" warning will stop illuminating.
During use, it's very unlikely you will run low or out of oxygen with between 28 (at worst) and 30 hours of supply unless you have a very stressful flight with a lot of faults or use the 10K ft pressurization.
There are conditions in which oxygen will be used at different rates based on stress factors.
Stressed rates are around 1.4X normal. When there have been no stress factors for 1 hour or more, a relaxed/calm rate of 0.8X is used. Many of these factors are tied to similar Master Warning lights.
IMPORTANT NOTE: With a severe loss of cabin pressure (cabin dump or canopy open) above selected pressurization altitude (10K or 26K ft) the system may not be able to repressurize the cabin in a steep climb. Level off or reduce climb until pressue is nearly equalized. Repressuring the cabin at high altitude after a pressure dump or open canopy will cause a rapid loss of liquid oxygen quantity.

    Increased Anxiety Oxygen usage (1.4x) when:
  • 10K ft pressurization selected
  • Engine Failed
  • Battery Draining
  • Low fuel (under 9500 lbs)
  • Take off or landing
  • Near Overspeed
  • Near Mach Stall
  • Low Speed Stall
  • Eng Unstart, Low RPM
  • High bank low speed, near ground
  • High descent rates over Mach 1.5
  • High Descent Rates close to the ground
  • Refueling (Refuel door open "READY/DISC")
  • High CIT (over 427C)
  • High EGT (Hot or higher)
  • High COG (over 25%)
  • Excessive hot breaking or ground speed
Lower than normal usage when:
No Anxiety for 1 hour

Fuel System:
On the same Fuel and Oxygen panel are various digital indicators of fuel quantity and COG Fuel Pump Switch. The digital COG % indicates the same as on the main panel. The digital fuel level displays are organized roughly in their positions on the aircraft. The previous Concorde fuel pump has been replaced by a custom pump with three positions. Auto (center) is the normal position for all modes except for minor corrections when attempting to land under 8K lbs fuel. The built-in fuel balancing system will maintain an ideal CG throughout the flight for all but the most unusual conditions. If you need to intervene, a brief click on FORE or AFT (Upper/lower 1/3 of the switch) returning the switch to STOP (click in the center) should do the trick.
Note: The fuel pump will not return to the auto position automatically.
PUMP_FWD Shown Right: Upper portion of handle clicked, handle positioned forward and forward pump light illuminated.
New (for July 2012): Fuel supply switches for the Left and Right engines have been added. If you are having trouble starting the engines, check these switches. They should be in the up position for normal operation. The auto-start feature normally toggles these to ON (up) at ignition.
In the October 2012 update, I added a display under the CG%: TGT% which informs the pilot what the CG fuel system is targeting for an ideal CG. This display normally indicates limits being placed on AFT CG. You can use this information to decide if you want to assist the computer with a small tweak. An indication of zero on this display means the fuel system is not currently targeting a CG limit, but rather letting the default fuel attrition system work its magic. The computer will conflict with your own settings if a large off-nominal condition is created by the pilot.
Note: Descending fuel loads over 39K lbs, the automatic system will not configure the CG for landing. The pilot will have to manage the CG with the pump switch.
The Fuel Dump switch does not have a safety and is a simple toggle. Its default position is OFF (down.) When clicked, the switch positions up and fuel is purged from all tanks at the rate of 41.6 lbs/sec. Another click when enabled stops the fuel dump.
The Fuel Dump switch is inhibited when the center tank four is 4060 lbs or less.

Fuel Annunciator:
On the far right of the main panel, the Fuel Annunciator indicates when a tank is empty by lighting bright and xFEED OPEN when all the tanks are being used for both engines. The later is the case when the Auto CG system is in its default non-managed state of fuel attrition balancing in which case the xFEED OPEN lamp is bright. In this state, FS defaults to tank usage based on its own internal logic and BOTH left and right tanks are used for both engines (no isolation.) If you click on this lamp you will force the Auto CG system OFF. You might do this if you dissagree with the CG balance and want to use the pump on the fuel panel to change it without the Auto system over-riding your adjustment.
NOTE: If you click on this lamp while it is lit, and it does not go out, is an indication the default attrition system is already operating. In this case, when the Auto system needs to operate, it will be disabled and the lamp will stay lit. In this situation you run the risk of the CG getting out of configuration. It is best to click on this lamp when it is unlit (meaning the Auto system is operating) and you want to make a temporary adjustment to the CG. It is not a good idea to click this lamp unless you are sure what you are doing. In normal operation, the lamp will flash on and off while switching between passive attrition mode and active management mode when enforcing CG limits. This will happen most often when the plane is heavy during climb and descent and at cruise when the CG has reached max.
At the bottom of the set of lamps is a test toggle. When clicked ALL the lamps will light up regardless of their logic state. Click again and the ones which should be in their off state will do so.
See the detailed explanation of this model's fuel balancing system for more explanation.
Defalt all off: F_annun1 Test ALL ON: F_annun2
CG Over-ride/Crossfeed:
F_annun3


How to set Mach Speed over Mach 3.00 in Flight Simulator:
Flight Simulator wasn't designed for aircraft which flew over the speed of the Concorde at the time the autopilot controls were designed, so Mach 3 was considered fast enough I suppose. Up to Mach 3, the Mach speed set window converts the current IAS into Mach but will not over M3.00. If you try to click on the Mach setting window past Mach 3.00, nothing happens. There is a work around which solves this problem. Enable IAS and advance the IAS window setting. Although the Mach display does not change, it will when you click on Mach hold after advancing the IAS bug upwards. With a little practice, it's quite easy to switch back and forth between IAS Hold, advance or decrement the setting, then switch to Mach Hold to see what you get. You will discover one knot is just over one hundreths of a Mach, so changing the IAS one knot will change the Mach by one digit (roughly.) The autopilot panel controls have been arranged to minimize the mouse movement when performing this operation.


Aircraft Specifications:

FUSELAGE:
Length: 103' 10"
Height: 18' 6"
Wing Area: 1,605 sq' (some sources claim 1,800 ft sq)
Wing Span: 55.6 ft
Wing Area (W/Chine): 1750 sqft
Wing Sweep: 52.6 deg
Wing Dihedral: 0 deg
V Stab Area: 70.2 sq'
Gross Weight (MTOW): 135,000 to 140,000+ lbs (Pilot Manual) 170,000 lbs Typical
Zero Fuel Weight: 56,500 to 60,000+ lbs (Pilot Manual)

ENGINES:
j58-7eng_stand (60K)
Weight(2): 13,000 lbs (6,500 lbs ea)
20' long, 4',5" wide
Model: (2ea) P+W JT11D-20B (J-58) Turbo Ramjet.
Static Thrust: 32,500lbs @ sea level
(45,000 lbs with after-burner)
Single Rotor, 9 stage 8:8:1 ratio compressor.
Note: Rolls-Royce/Snecma Olympus 593 (Concorde) = 15:1:1
General Electric CF6 (747) = 30:5:1
ENGINT (79K)
TO_THR (9K)Bleed Air Bypass Transition: CIT 85C to 115C, Mach 1.8 to 2.0
Military Max Thrust sea level: 70% of total
Military Max Thrust high alt: 28% of total
AB Min detent Thrust at sea level: 85% of total
AB Min detent Thrust high alt: 55% of total
Starting RPM: 3,200
Typical Idle RPM: 3,975
Max RPM: 7460?
Min RPM above M1.5: 6100
Typical Cruise RPM: 7050-7150
Overspeed RPM: 7450 < 300C CIT, 7300 > 300C CIT
Cruise Inlet/Engine power ratio: 80%/20%
Core Airflow: 450 lb/s
Max Inlet Spike Movement = 26 inches.
Inlet Shock "start" movement: Between Mach 1.6 and 1.8
Inlet Guide Vane (IGV) Transition: Axial/Cambered = apprx CIT 85-115C Mach 1.9 and above.
INLET (44K)
ENG_FLOW (76K)
INLETIGV (89K)


FUEL:
Fuel Load (JP-7) at 100,000 lbs Gross Weight: 11,570 lbs
Fuel Capacity: (real world) 83,302 lbs JP-7 (12,200 US gal @6.9 lbs/gal)
Fuel Capacity: (this model) 80,653 lbs FS "JetA" (12,038 US gal @6.7 lbs/gal)
Unusable: 32.4 Gal (217 lbs)
Standard temperatures and pressures:
Rated Cruise: Mach 3.20 @80,000ft
Fuel Rate at Ground Idle: 4800 - 6300 lbs/hr
Fuel Rate MAX Take Off Full AB: 80,000+ (both engines)
Fuel Rate at refuel speed and alt: 24K lbs/hr
Fuel Rate (rated cruise): 36-41,000lbs/hr
Fuel Rate (Average Climb): 22,500 lbs/hr
Fuel Rate (Average Descent): 16,500 lbs/hr
Full Fuel:
Fuel Dump Rate: 2,500 lbs/minute (42.08/sec) until tank4/6a reaches 4700 lbs, then auto-terminates.

PERFORMANCE:
Min Take off Runway length: 9,000ft. (with after-burner)
Min land Runway length: 7000ft (10K lbs or less fuel)
Typical Runway Take off Roll (45K lbs fuel): 4800ft
Max Crosswind landing: 25 knots dry, 20 knots wet.
Caution: 16+ knots @ 55+ degrees
Prohibited: 25+ knots @ 20+ degrees
Gear Extended Limit: 300 KEAS/330 KIAS
Gear Cycle Limit: 10 times per flight
Max Ground Tire Speed: 238 KEAS, 239 KIAS, 275 MPH
Tire Cooling: 9 minutes for every 14,000ft or 2.75 miles of taxi distance at 70 deg F.
Max Taxi Speed (recommended): 40 MPH(35 KIAS)
TirePressure: 400 Psi
Take off Tire Failure: 10K ft @72 deg F
Max initial braking speed 10K lbs fuel: 209 KIAS @70 deg F
"Brake Walk": Oscillations @ 10 cycles per second.
Anti-Skid Min Speed: 10 knots
Min Ejection Altitude: 15,000ft
Touch Down Vertical Speed: Typical- 50 to 100 fps, Max- 600 fps
Landing Threshold Pitch: 10 deg
Landing Threshold AOA: 9.5 deg>
Pressurization (normal Cruise:) 26K ft:
2ea 10 Liters Oxygen
Standby = 1 ea 10 Liters Oxygen
Tank Pressure 65 - 100 psi
Consumption: 1 Liter/hr for two people
10K ft:
1.4 Liter/Hr

V Speeds (45K lbs fuel):
V1 = 156KIAS (acceleration check speed)
Vr = 180 KIAS, (full weight) = 205KIAS
V2 = 210 KIAS
66K lbs fuel:(full TO Weight) = 220KIAS

Max Speed: Mach 3.45/558 KIAS RANGE_CEILING (176K)
From SR71 flight manual section 5-8 Maximum Mach:
" Mach 3.2 is the design Mach number. Mach 3.17 is the maximum scheduled cruise speed recommended for normal operations. However, when authorized by the commander, speeds up to Mach 3.3 may be flown if the limit CIT of 427C is not exceeded."
Maximum Design Structural Limitation: 500 KEAS (559 KIAS.)
This speed would be exceeded if the plane was flown above Mach 3.0 below 65 thousand feet.
Recommended Operational Ceiling: 85,000ft (model tested stable to standard weather.) Altitudes much higher than this are rare in download weather.
Normal Cruise Altitude: 79K ft westbound, 80K ft Eastbound.
Range: 3,250 miles un-refueled (based on ideal static weather, no wind)
Initial Cruise Speed: M3.0 @ 72K ft.
Mach Cruise Bank Angle Limit: 35 degrees
Max Bank Angle during Climb: 45 degrees
Max Rate of climb: 11,810 ft/min (60 m/s) - 9999 under AP control
Max Rate of Descent: 1 mach per 3 minutes above Mach 1.8 (roughly exceeding sustained -6200 fpm 75K ft through 60K ft)
Cruise Range Loss from Turn: 2.5 miles per 10 degrees

Minimum Single Engine Approach Speed = 200 KIAS 25,000 lbs fuel.
Minimum Go Around Alt = 300 ft.

Temperatures:
From 600 to 900+ degrees Fahrenheit on the airframe.
Temperatures on the J-58 engine exhaust reach 3200 degrees F.

Min Operating Air Temperature = -75 deg C

Sub-Mach Max Climb Speed (no turbulence): 400 KEAS
Max Performance Climb Speed: 450 KEAS
Sub-Mach Max Climb Speed (max turb penetration): 350 KEAS

Minimum Turn Airspeed: 220 KIAS

Landing Speeds:

Fuel lbs

Approach Spd

Touchdown Spd

<= 10K

175 KIAS

155 KIAS

20K

185

165

25K

190

170

30K

195

175

40K MLW

205

185

Typical AOA at the above speeds and weights are 9 to 10 degrees, not to exceed 14 degrees (tail strike.)

Flight AOA Limits:
Max below 25K ft = 18 deg
Max Subsonic 25K+ ft = +10 deg
Max Supersonic 25K+ ft to 70K ft = +8 deg
Max Supersonic 70,000+ ft = +6 deg

Drag Chute deploy:
5 seconds full deploy after activated on touch down. 1/2 G decel. Nosewheel contact required before activation with cross wind.
Max Drag Chute Deploy Speed: 210 KIAS
Drag Chute Attachment fail Speed: 30K+ lbs fuel
Min chute Jettison Speed: 55 KIAS

Max Sub-Mach Climb to Cruise:
Full Stop Break Release to 24K ft in three minutes.

Temperatures between -55 to -70 C:
Design Mach Speed = 3.2 (above 35Kft)
Maximum Operational Mach = 3.35
Overspeed Mach =3.45
Maximum Indicated Air Speed = 559 KIAS, 500 KEAS.

Max Safe Altitude = 85Kft (without special auth.)

Max Rated Altitude = 92K ft (can go higher when weather permits.)

Max Pitch at cruise = 7 deg (Speed loss/Stall Instability @ 6.0 deg)
PITCH WARNING!!!: Do not let pitch rise above +7 deg or below level on the Artificial Horizon while above Mach 3.0

Min Supersonic Airspeed = 310 KEAS
Note: Descend rapidly if the weather system causes a sudden drop in EAS to a value near this speed.
Mach 3 stall: Below 240 KIAS

No Power Glide (80K ft Mach 3.2):
375KIAS @ -11,600 ft/min
6 minutes to 10Kft (102nm)

Ground Lift effect: Within 30 ft.

Peak Aerodynamic Pressure: Apprx 670 lbs/sq ft (Dypsey Doodle Climb 450 KEAS through 35K ft.)

Refueling:
Normal Alt- 25K - 35K ft (35K feet with latest tankers.)
AOA 3 deg low fuel
AOA 6 degrees full tanks
Typical distance between tanking: 2000 miles
Refuel Rate: 6,000 lbs/min
Typical Refuel Time: 15 minutes

Max Deceleration above M 1.8 = 1 mach per 3 minutes
Below Mach 1.8 = No limit

MLW: Not Limited (suggested 40K lbs fuel max)
Note: APP AP is very unstable at this weight
Normal Landing weight: 10K lbs fuel or less
Touch and Go Limit: 25K lbs fuel

CIT Compressor Inlet Temperature:

Max Inlet Temperatures (mach 2.8 @85Klbs gross weight)

SAT(C)

CIT(C)

-69

250

-61

270

-57

280

-52

290

-44

310

(mach 3.0 @85Klbs gross weight)-

SAT(C)

CIT(C)

-67

300

-60

320

-57

328

-52

340

-45

360

Nominal Inlet Temperatures (Mach 3.2 20K lbs fuel)

SAT(C)

CIT(C)

-66.8

350 (typical Cruise)

-59.8

370

-56.5

380/Max: 427C (801F)@ M 3.38

-52.9

390

-49.5

400

-46.2

410

RPM:
cit_rpm_chart (161K)

EGT:
Idle: ~430C @ sea level (typical)
Max start temp (idle) = 565 C
Normal Cruise Range: 780 - 820C
Continuous Limit: 830C
Emergency Zone = 805 - 845 C up to 15 minutes
Red Zone: 900 C up to 2 minutes
950 C up to 15 seconds

egt_cit_chart (167K)

COG:
Modeled MAC in FS2004 = 51 ft (wing + forward fuselage chine).
Typical range: Forward- +17% to Aft- + 24%
Ideal Take off: 17 % (Published), Typical: 20%
Max at cruise: +25%
Max Take off and land: +22
Max below Mach 0.9: +24
Min COG above Mach 1.8 and 11,570 lbs fuel: +17
Min below Mach 1.8 and 11,570 lbs fuel: +14.5
Ideal Landing: +21.0 to +22.0
Max at Mach 3.30 = 24.3% MAC

Trim Limits:Subsonic level=-1.5 deg nose down.
Supersonic level: Min=+0.5 @ M2.6 (normal 3.1 at full weight.)
Max=-1.5 @ 25% COG (normal 0 at Mach 3.0 near 24% COG.

Mach 3 Environment Temps:
Interior: 300 deg F
Nose: 800 deg F
Windshield: 600 deg F
Exhaust: 1,200 deg F (649C)

Oil Pressure:
Min safe operating = 35 PSI
Normal = 40-60 PSI

Fuel Pressure:
7-9 Psi

Hydraulic Pressure:
Normal = 2200 - 3000 psi at or above 3000 Engine RPM
Reduced Control = down to 1500 RPM Control Failure = below 1500 RPM

Electrical:
2ea 60KVA direct drive generators. 155/200 volt, 400 cycle.
2ea 28 volt, 25 amp/hour batteries.
Emergency AC buss (supplied by battery 1): 1KVA.
Battery Duration (essential equip only) 40 minutes.
External MD-3 or MD-4 power connector.

G Load Limits:
Mach 2 and Less (below 50K ft): -.2 to +3.5
Mach 2 and less (above 50K ft): -.2 to 2.5
Mach 2 to 2.6: -.1 to +2.0
Mach 2.6 to 3.2: -.1 to 1.5

Min Airspeed Restrictions:
Supersonic: 310 KEAS
Subsonic and >= 25 Kft: 300 KEAS
Subsonic and < 25 Kft: 145 KIAS

Pitch Trim: The model under ordinary fuel and speed operation and auto-pilot control will conform to the following flight trim settings:
TRIM (32K)


--------------------- FLIGHT PROCEDURES: ----------------------

This general overview of technique for flying this aircraft in FSX is not real-world but based on manipulating the sim to obtain consistent results. Unrealistic weather conditions strongly affect performance. The details here are also provided as checklist and reference items within the panel Kneepad feature. New for sr2012Updt1c are htm checkist and reference files elliminating the problems the previous text files produced.

o PRE START PREPARATION:
FLIGHT PLAN loaded into GPS or another navigator that performs turn prediction. FS2004 GPS turns about 2.8 miles prior to the waypoint at high speed. This is JUST enough to maintain control during turns. At cruise, waypoints should be 500 miles apart or more if they have moderate turns, No-turn waypoints can be as close as 100 miles. When flying over water to your destination (ATC hate mach speed in their space) a careful flight Plan will include a way point close to the coast (assuming your destination is somewhat inland) for use as a descent calculation target. This is explained in the descent profile later.

Fuel Loading:
To provide a wider performance margin on take off in case of an engine loss, the Air Force flew the SR-71 with one of three fuel loads:
45, 55, or 65K lbs.
If using SFP or NAV3, range and fuel estimating should be close using the following table:

CLIMB

CRUISE

DESCENT

SPEED

900

1780

700

FUEL RATE

28900

38100

12300

VERTICAL RATE

1920(ave)

2900(ave)

ALT

80000

Fuel Tank Diagram

(EDITED for update sr2012Updt1b) Note: The SR71 is capable of fuel balancing automatically for the entire flight flight and approach. Automatic fuel tank selection and tank attrition schedule built into the model simulates the auto transfer system AS LONG AS you load the tank percentage below on the ground and left and right tanks are balanced.
The balancing system is in auto mode when the FORE AFT pump switch is in the center (AUTO) position.

Easy Rule of thumb:
To set typical take off weight of 45K lbs, set all the tanks in the FS fuel menu to 56%. This will provide a COG close to 20% for take off. Any COG between 19% and 22% is acceptable for take off or landing.
To set 55.6K load: all tanks 69%
To set 66K load: all tanks 83%
Warning: There are EIGHT(8) fuel tanks in the FS fuel dialog. Failure to set ALL of them to the same percentage may cause the auto balancing system to provide less than optimum performance. This system of setting all the tanks to the same percentage was adopted to make fueling the SR-71 simple for the pilot even though the CG system is very complex.

Detailed explanation of this model's fuel balancing system.
1 hour or less than 1000 miles: Use 45K fuel load.
Up to 1.5 hours or 1000 to 1500 miles: Use 55K fuel load.
1.5 to 2.0 hours or 1500 to 2500 miles: Use 66K fuel load.

FS Fuel Dialog:

Ltip = Tanks 1 + 1a
Rtip = Tanks 1 + 1a
Lmain = Tank 3 L
Rmain = Tank 3 R
Cntr = Tank 2 Foward Trim
Cntr2 = Tanks 4 + 6a Rear Trim
Laux = Tank 5 + 6b
Raux = Tank 5 + 6b

Fuel distribution is as follows (rough):

< NOSE to TAIL(111ft)

>

1,1a

2

3LR

4,6a

5,6b

<  pilot

LRtip

Cntr

LRmain

Cntr2

LRaux >

|

<wing

<engCTR>

wing>

o

o

Min Usable:
1 = 2300 lbs
2 = 3400 lbs
4 = 2400 lbs
5= 1900 lbs
Min Landing Fuel Weight:
5000 lbs
These tank assignments and positions are based on FS2004/FSX built-in default tank attrition schedule which chooses the order in which tanks deplete until empty. A complex system of tank switching at capacities enhance the attrition for optimum CG and trim near Mach 3 and above. Habu pilots considered 60,000+ lbs fuel weight a "heavy" jet. At the typical take off weight of 45K Lbs fuel, you'll find the plane nimble and fast-climbing. If you need a fuel load over 70K lbs, it's best to take off with the default loads of 45K, 55.6K or 66K lbs (depending on when you can intercept the tanker) and plan on an air refuel.
IMPORTANT: At Fuel Weight below ~8000 lbs OR over 39K lbs OR tank 3 is over 3100 lbs total, the autmatic system will not maintain the landing CG of 21.5%. Landing below 10,000 lbs normal landing weight or over 39,000 lbs will require the pilot to use the pump switch manually to compensate. Also, it may not be possible to get the CG under 22.0% for landing when over 27,500 lbs fuel.
END FUEL PREP.

WEATHER PREP:

The SR71 is sensitive to pressure and temperature more than wind speed because of the high altitude. Near the flight limits large pressure changes can throw the flight model well beyond its operational limits. Pressures over 30.10 inHg are problematic because they force you to fly very high (which can be fun, but increasingly risky.)
Recent retail versions of FSUIPC for FSX provide temperature, wind and pressure smoothing which greatly enhance the flyability of this aircraft when using Jeppeson weather. Very low presure will force the pilot to fly altitudes ~74K ft. Active Sky 2012 SP1 is the preferred weather source and does not require FSUIPC for smoothing.
Note: At the time of this writing, there is a problem with using FSUIPC wind smoothing while using external weather programs resulting in zero winds above 52,000ft.

Check for strength and direction of prevailing winds. Typically, in the northern hemisphere, you will have mostly head winds traveling West and tail winds heading East. I add 1000 lbs when going West and subtract 1000 from the estimate going East. The exception would be flights more N/S than E/W where I don't modify the estimate.

80,000ft should be used for flights East and 79,000 for west. Although the model supports flights up to 85K ft (normal limit is 82K ft) with pure Jeppeson-only weather source, unstable weather over coastal transition boundaries (300 - 500 miles from land crossing over large bodies of water) may cause highly unstable flight. Engine power is reduced by periods of extreme off axis air flow. The payware version of FSUIPC has a wind smoothing feature which helps reduce rapid wind axis changes.
Active Sky also solves this problem.

Weatherset: A useful tool for checking the quality of the weather generation is a free program which comes packaged with FSUIPC called Weatherset. FS2004 and FSX users should use Weatherset2. This program displays all the weather data being sent to FSUIPC by the weather program in a numerical display (rather than the FS weather dialog tabbed graphical display.) This lets you see all the current weather settings at a glance without scrolling or tabbing.

Another useful tool comes with the online multiplayer connection program FSINN. Along with a large package of tools in the main FS menu is the "Pressure" indicator. This places a current pressure display in the sim so you can see what the current pressure is at all times without switching to the desktop. As you get more experienced, you will come to expect certain IAS readings at certain altitudes.
This panel has a special enhancement to the Altimeter to display relative pressure changes.
Higher or lower than normal air speeds at Mach 3.2 are an indication you are flying in unusually low or high pressure. The Altimeter has a special enhancement which shows simply at a glance if the pressure is changing and whether it's normal, high or low. This can help the pilot take pro-active measures to reduce the effects of pressure changes.

FSUIPC-
The following settings in the WINDS section of FSUIPC are necessary to smooth the wind for Mach speed flight. If you are using the free version, you cannot set this resulting in less than satisfying weather conditions in all aircraft:
CHECK "Smooth Changes"
Knots or degrees/second = 0
OR for this many seconds for each 1 degree = 2
After weather clear delay smoothing by seconds = 0
CHECK "smooth only when airborne."
Note: At the time of this writing, there is a problem with using FSUIPC wind smoothing while using external weather programs resulting in zero winds above 52,000ft.

Active Sky Settings-
Without FSIUPC, Active Sky 2012 SP1 users will get the best wind smoothing in DWC mode with rate of change slider set to zero. When using Active Sky AND FSUIPC, set all FSUIPC weather features to off.
Suggested Option Settings using AS 2012 SP2:

    General
  1. Force Destination WX Zone = Checked (With a flight plane, allows the plane to enter landing conditions further from the runway.)
  2. Direct Weather Control = Checked (provides best wind, temperature, and pressure smoothing at high speed.)
  3. Create Additional Stations = Checked (if the stations in your flight area are too sparce, AS will create some virtual staytions which help fill in gaps for smoother transitions.)
  4. Enhance Route Coverage = Optional (does the same as Additional Stations, but are created based on the imported flight plan.)
  5. Local Station Writes with DWC = Checked (DWC does not use the Jeppeson-like "Standard" mode of creating descrete stations around the aircraft. Local Writes creates a "hybrid" mode where some local stations are added to the global environment DWC creates which improves local accuracy and can help reduce temperature spikes in some cases.)
  6. Dynamic Rate of Change = 0% (if this is not set properly, FSX will create morphed weather which over time has little or no relationship to the weather AS has created.
    Cloud Options
  1. Maximum Cloud Turbulence = 10% (AS 2012 SP2 Beta5 can create turbulence effects even when the aircraft is not in a cloud (which is always the case above 60K ft where the SR flies. When Cloud turb is added to Wind turb, the effect is devestating.)
  2. (Misc) Prevent Cloud Redraws (FSX DWC Mode) = Checked (helps existing clouds to stay around longer instead of "popping" on and off frequently)
    Wind Options
  1. Maximum Wind Turbulence = 50% or less (If this is set too high, AS 2012 SP2 Beta 5 can create thunderstorm turbulence at very high altitude which can cause the plane to lose control.)
There are no recommended settings for other options which are less important than the ones mnetioned above.

NOTE on PRESSURE: In practice, pressures during M3+ flight OVER 1024.4mb (30.25Hg) or UNDER 997.3mb (29.45Hg) are problematic. You can expect to have to climb very high (90K+) to obtain M3 or descend very low (72K ft and under Mach 3) to avoid stall near these pressures. Avoid IAS over 500 or under 380 at cruise. I cannot stress enough that the most maintenance-free flights will have cruise speeds near 410KIAS/360KEAS (the middle of the model's stability range.)

END WEATHER PREP. PRE-START PREPARATION CONTINUES...

PRESET THE AUTOPILOT to have AutoThrottle ENABLED, set initial altitude (usually 10,000 AGL to 28,000) 255 knots IAS on AP bug (for low alt restriction) and 4500 ft/min climb rate. When using normal unrestricted climb, set initial alt to 28K ft and AT IAS bug to 450 KIAS. This will hold close to 400 IAS (350 KEAS.)
Alternatively, use the KEAS HOLD in the Refuel section (prefered) to hold climb and decent speeds.

Switch NavGPS switch to GPS (note: GPS mode disables ILS approach so you need to toggle the switch back to NAV during automated ILS approach.)
END PRE-START PREP

o Start-up: If necessary, activate the fuel pumps with control-shift-F4 or the fuel pump valves in the fuel panel. on the left of the main panel, click and HOLD each engine start button until ignition (apprx 22% RPM.) Alternatively, activate the autostart sequence with shift-e. The Chevy V8s will spool up loudly. Once the engine ignites, the TEB counter will lower by one (starts at 16) to indicate one shot of Triethylborane was used to start the engine.

o Taxi:
Move all control surfaces and visually verify correct operation. When engines have stabilized, start taxi not exceeding 20 knots ground speed. Avoid rough ground so as not to damage the gear or debris intake damaging the engines.
Frequent breaking will be necessary due to high engine idle RPM.
Warm surface temps and frequent breaking will activate the yellow "TIRE" warning.

o Position and Run-Up:
-Position on the runway into the wind, set the breaks and bring up the autopilot.
-Inspect all gauges and switches for correct position for take off. -Place the DERICH switch in the up (enabled) position.
Wait for yellow TIRE warning to extinguish.
-Activate Pitot Heat and also De-Ice if you are passing through freezing clouds on the way up.
-Check Roll, Pitch and Yaw trims for zero position. Operate pitch roll and yaw stick controls and observe they all move to maximum positions (100%) and return to zero.
-Tap the numpad-5 key (with numpad off) to center your control inputs.
-With breaks set, smoothly advance the engines to full military (80% green) for correct operation. IGV lights should illuminate. Return throttle to idle. IGV lights should go out.
-Set decision altitude bug to 350 ft on the radar altimiter.
-Test proper IAS hold operation by briefly clicking on the IAS hold in the AP. The bug should stay where you placed it. If it moves, reset it. Next time you activate it, it will not move. Set throttle back to idle.
-Double check everything.

o Take-off:
KIAS vs KEAS:
Equivalent Air Speed is used for high speed flight. You will see KIAS (Indicated Airpseed) or KEAS used in specifications and procedures depending on documentation available or whether the flight mode is subsonic or supersonic.
Set the AP AT IAS bug to 255 KIAS for restriction or 464 KIAS (to obtain an initial 400 KEAS) non-restricted climb. Preset your desired initial climb rate. This is typically between 7000 and 10,000 ft per min. (The default is 1000.)

-Smoothly advance the throttle to 80% (full military.)
-Release the breaks and engage the Afterburner (shift-F4.) Throttle position numbers will change from green to white and the TEB counter will drop another number to ignite the ABs.
-Activate full take-off power (TO/GA) by tapping the key combo Shift-Alt-G or click on the left throttle position number next to the top of the throttle (the numbers will change to orange or dissapear.) Using this feature will help prevent over speed on the engines.
-Passing 156 knots (speed check) you should be over half way through your roll distance. Be prepared to pull the throttle back soon to avoid EGT limits in hot weather or conform to any area speed restriction which might be in place. If your climb is unrestricted, keep the throttle in TO/GA mode through the initial climb.
Observe EGT temperature and do not advance throttle beyond 850C unless absolutely necessary. 900C can only be used for 2 minutes maximum and 950C has a 15 second limit. Normally, the de-rich system will prevent exceeding 960C on take off.
Note: At standard temperatures (50-60 degrees F) full throttle will rarely exceed 850C EGT.
Note: Very warm surface temps will limit climb rate.

Crossing 156 knots Indicated during roll, reduce throttle to apprx 85% to prevent over-shooting terminal area speed restriction of 250 KIAS when in ATC control. Otherwise, when non-restricted stay in TOGA mode.
-At full weight (66K lbs fuel) rotate the nose steadily at apprx 205 KIAS to 10 degree pitch and hold until lift-off into a 2000 ft/min climb (strong down pressure will be required to prevent nose up.)
-When using 45K lbs fuel (Normal loading) use 180 KIAS rotation speed.
-On positive climb raise gear immediately. Gear will break above 300 KEAS/330 KIAS. Retain AB through climb.
-Engage AP (Z) and tap Contrl-T to temporarily hold climb profile @ 1,500 - 2000 ft/min and click IAS speed hold 255 KIAS in the autopilot (when flying in restricted space.) Closing on 250 KIAS (restricted) disengage AB and click ALT hold in the autopilot with the mouse. This will happen very quickly!!! The 255 bug setting you set earlier will hold close to the 250 KIAS in restricted space.
-Tap Cntrl-H to hold current heading.
-Unrestricted, you must first obtain an initial airspeed of 300+ KIAS while at a low climb rate. Continue to climb on TO/GA and set best climb rate to hold as close to 400 KIAS as possible transitioning to IAS speed hold of 465 KIAS when the speed nears 400 KIAS (350 KEAS.)

Note: Clicking the speed hold with the mouse has a different effect than using the key combo Control-R.
When using the keys, the AT will be set to the CURRENT air speed of the plane. The mouse will set the AT to the TARGET speed set in the AP bug control.

At this point the plane will be under stable autopilot control in trimmed flight. Resticted: As the speed reaches 250KIAS increase normal climb to 3500 ft.min.
Unrestricted: Max climb off the runway with gear up can initially be as high as 10,000 ft/min on full throttle/AB after passing 300 KIAS using Autopilot VS. Sustainable climb using 7000 ft/min is possible up to 24K ft in normal temperature conditions.

o Terminal maneuvers:
Use ATC instructions or bring up the navigation aids (GPS etc) and navigate to intercept the 1st flight plan waypoint. Observe the 250KIAS speed restriction when flying near controlled airspace. Engage autopilot NAV mode to start GPS flight plan control. External control programs require staying in HDG mode.

-Engage Yaw Damper (Surface Limiter) above 330 knots Indicated (LIMITER in the annunciator.)
-Crossing 18K ft, reset altimeter to 29.92. Crossing Mach .85 set Mach Hold 0.90 for cruise to tanker circuit. Otherwise, hold M.9 for your cruise-climb to unrestricted Mach climb area.
On long flights where fuel top-off is necessary, intercept the tanker altitude @ 28 - 35Kft.
Older tankers require 25K - 30K feet. In turbulence, use 350 KEAS for the sub-mach climb, otherwise, use 400KIAS. New tankers modified for the SR71 can use 34K - 35K ft.
Note1: 35,000ft and 350KIAS is the highest and fastest the plane can fly and still remain sub-mach (apprx M.97) 28,000ft and 400 KIAS is more typical providing M.95.
Note2: Max turbulent speed is 350KEAS so only use 400 KEAS in calm conditions.

o Refueling:
Intercept the tanker between 280 and 305 KIAS or Mach 0.85 (whichever is slower.) Under current model configuration, fuel top-off is typically filling ALL available tanks. When refueling with take off COG at 22%, a COG over 24% will result in a warning. The warning will clear as soon as speed in the climb over Mach .9 is obtained. Using the supplied refuel gauge, enable the RDY/DISC button so "0000" is displayed on both top and bottom rows of numbers and click the "Air Refuel" switch.
The rate is @6500 lbs/min, all tanks simul-filled 5-10 minutes at 56-70 psi. The refueling gauge operation is also discussed in the Special Gauges section above.
At typical tanking speed of @280 - 300KIAS, and full fuel, the pitch attitude will be around 5+ degrees.
Marginal military power at high pitch can be compensated by enabling AB on one engine and using differential engine control to compensate for yaw.

o Dipsy Doodle (modified for FS9/FSX):
This is the most common technique used to accelerate into the mach climb after refueling to a heavy condition which helps to transition through the high drag of mach 1 at low pitch. After refueling, set AT hold for speed Mach .9, engage AB (or remaining AB if one side already enabled) and set climb rate to 2000 ft/min.
If you have refueled at 35K ft, set Mach hold to 0.95.
Between 30K-32K ft increase ATspeed bug to Mach 0.95. Passing M0.95 and 33K ft or above set AT bug initially for 530 (for 450 KEAS climb) or 470 (for 400 KEAS climb) and start a -2000 descent through Mach 1.15. Passing 390 KIAS when using 400 EAS climb increase climb to +2500 fpm. When using 450 "Normal" schedule, set IAS hold to 530 KIAS and when crossing 450 KIAS set climb to +2000. As EAS in the Triple gauge crosses 400 or 450 without blinking, engage EAS hold.
When using 400, set climb rate to +3500. When using 450, set climb rate to +3000.

o Mach Climb:
There are two common climb speed "schedules" used:
450 KEAS which is the "normal" high speed climb into a high risk area after tanking. Fuel burn rates are fairly high reaching 40-44K lbs/hr at Mach 3. On a 1.5 hour flight, around 2000 lbs more fuel will be used than the 400 EAS schedule. This profile gets you over the target area at high speed, but low altitude again soon for re-tanking. Climb discussions in most books about the SR mention this profile as it's commonly used for incursions close to enemy recon targets.
400 KEAS is used when longer range is needed between refueling. Mach 3 fuel rate is closer to 38K lbs/hr. This profile gets your plane higher sooner, but establishes cruise at a lower initial speed. The world record flights between Beale and Farnborough used a profile similar to the 400 KEAS schedule.

When flying light (45K lbs fuel or less) and refueling is not used, it's possible to start the climb without the Dipsey Doodle. Starting from level at Mach .95, engage the AB and set the AT bug to 470 (to obtain 400 KEAS) or 530 (to obtain 450 KEAS) and ease into the desired climb rate starting shallow passing 380 KEAS or 420 respectively. As in the Dipsy Doodle climb, the initial climb target is 74K feet at Mach 3.0.

MACH MODE:
NOTE: FS9 does not show the whole digit mach number when the speed is over Mach 3.
At Mach 3.0 it will indicate 3.00 although the set speed may be much higher.
At apprx Mach 2.80 to Mach 2.85 switch autopilot to MACH. Observe these two things:
1) The speed hold bug in the airspeed gauge should be near the actual speed indication on the gauge.
2) The mach bug indication in the AP should read between 3.00 and 3.30 while the air speed gauge indicates near Mach 3 or more.

Adjust Mach speed using this procedure: How to set Mach 3+ in FSX

At high fuel loads and 450 KEAS climb speed, climb rate is slowly decreased as follows:
Note: These are guides. Actual operation may vary depending on weight and weather conditions.
60Kft = 1500 ft/min
70Kft = 1200 ft/min
75K ft = 1000 ft/min
78K ft = 700 ft/min
Within 2K feet of target = 500 ft/min

Alternatively for more fuel savings, use the Concorde style "Cruise Climb" at 100 ft/min above 60K ft. You should cross 74K ft at Mach 3.0. The 400 KEAS climb profile can use more aggressive climb rates than the 450 KEAS profile. Cruise Climb can also help getting through rough weather areas where a slow increase in speed and altitude is much better tolerated than blasting up to target altitude and speed and trying to hold it.

Note: FS9 setting for max climb in Auto-Throttle is to set 530 IAS, then engaging KEAS Hold crossing 450 KEAS.

While in turbulence, Mach Climb will use 350 KEAS.
High Speed Climb:
1) Set required altitude in AP.
2) Set 530 KIAS in the AP bug to capture initial speed of 450 KEAS on the triple gauge for the 450 KEAS profile. Engage KEAS Hold as you cross the desired profile speed
3) 2000 ft/min when good climb speed is obtained. Can use 3000 at low weights and short distances.
4) Beale to Farnbourough world record flight for instance uses 400 KEAS and 3500ft/min initially for the Mach 3+ cruise legs.
5) Engage After-Burner (note: AB will stay engaged throughout flight until descent.)

COG:
At take-off the plane is fairly evenly balanced. Too high COG at take off makes it possible to have a tail strike from rapid rotation. During flight the #1 tank fuel burns off 1st- slowly moving the COG rearward for mach cruise. During approach and landing, normal fuel attrition and automatic tank switching will result in COG which is in the typical range for landing (unless the pilot has used unusual fuel loading.)

As you approach Mach 2.83 at near 70K ft, engage Mach hold M 3.0. Continue shallow climb and watch fuel flow. As flow drops below 20K lbs/engine, slowly advance Mach hold to stay under 20K lbs/hr until desired speed is reached.

Cruise Climb:
Nearing 60Kft. reduce climb in a profile called "cruise climb" to around 100ft/min up to the target altitude. It's not unusual to have to change altitude in small increments once reaching target altitude to optimize the flight for weather conditions. Crossing Mach 3.0 fuel rate will typically reach 40K - 44K lbs/hr. As you reach M 3.2, rates may drop to 36K-38K lbs/hr or less. Above Mach 3.2 fuel rate will increase again. Occasional extreme changes in weather server data may cause extremely high or low fuel rates.


----------------------- WARNINGS FAILURES AND PROCEDURES: -----------------------

!!!! PITCH WARNING !!!!
Avoid pitches in the AI display over 5 degrees. At apprx 5.5 degrees stall is imminent above Mach 3. WARNING!!!: DO NOT ALLOW PITCH on the Attitude Indicator to drop below zero above Mach 2. Temperatures warmer than -58 deg C and over 72K ft are marginal operation. Climb to cooler temperatures or hold present altitude, or descend to maintain pitch under 5 degrees.
Structural failure will occur @ 520 KIAS.
Static Temperatures of -75 C or lower will reduce engine output to less than max rated power.
Deep Stall will begin above 60K ft and slower than 310 KIAS. It starts as a "twitchy" altitude hold where it appears the AP has trouble holding the altitude and the needle always sits just below the set altitude. I strongly advise not flying under 380 KIAS at or over M3.0. You also risk Unstarts and compressor stalls the closer to 300 KIAS you get.

AERODYNAMIC STALL PROCEDURE:
- Reduce climb rate, level off, or descend as conditions require. Maintain highest safe mach. Do not exceed M3.45. When pitch attitude drops to stable condition, maintain profile (no matter how long it takes) until a typical pitch of .1 to 4.8 degrees is obtained. Only then can climb be re-engaged.
Note: Sometimes conditions combine to limit engine power AND provide excessive pitch. This will seem like a no-win as the temperature limits the engine so you cannot increase speed and lower the pitch. Descend or maintain altitude until stable flight is obtained. If the problem is caused by too-warm temps heating up the CIT and EGT, it's often best to avoid acceleration for a while. This will help the engine cool enough so you can begin a moderate climb into cooler air.

ENGINE COMPRESSOR STALLS (no unstart lights:)
- Caused by:
1) Excessive AOA during climb (see specs section.) Reduce climb rate, level out, or descend rapidly.
2) Airspeed too low (below 350 KEAS) during descent rates greater than 1500 ft/min. Increase descent until faster than 350 KEAS.
Restart engine. Tap Shift-Cntrl-F4 if the first auto-start sequence fails. The auto-start sequence will usually try three times before giving up.
If you continue to have trouble starting engines, check the Fuel Switches on the Fuel and Oxygen Panel.

ENGINE UNSTARTS:
- Caused by improper spike position, decelerating too quickly while above Mach 1.5, or stalling the aircraft below 300 KIAS while above Mach 3.0.
Place spike in proper position (or return to AUTO [DOWN].) Continue to monitor for correct position during rapid deceleration. Reduce climb, level out, or descend rapidly (-7000 ft/min or more) to build speed above 350 KEAS.
Wait for auto-restart sequence. If auto-start fails, hold start button on main panel until ignition. Alternatively, press the key sequence Contrl-E. Historically, engines could not be restarted until descending and decelerating below Mach 1.7. This limitation is not emulated at this time but may be in the future. Unstarts will not happen below mach 1.5. but compressor stalls can occur from excessive bank turns at low speed.
If you continue to have trouble starting engines, check the Fuel Switches on the Fuel and Oxygen Panel.

!!!! ENGINE POWER WARNING !!!!
High pitches due to excessive climb rate, severe weather changes, or inattentiveness to power profile may result in loss of power at max throttle.
Too-high pitch may cause power loss.
Temperatures warmer than -55 degrees C or colder than -75 degrees C may cause power loss.
POWER LOSS PROCEDURE:
Level out or descend gradually until pitch and temperature permit power recovery. Avoid maintaining flight conditions where The auto-throttle stays at 100% when at mach cruise. In normal mach 3+ cruise engine RPM is between 85 and 95%.

!!!! Engine Overheat Warning !!!!
If the CIT temps are permitted to hold or exceed 428C continuously for 30 minutes or more, one engine will be commanded to fail. Each engine has a 50% chance of failure at this temperature. A failed engine cannot be restarted. The non-failed engine will continue to operate. The rapid reduction in speed and temperature will prevent damaging heat in the remaining engine. With one engine operating on AB, you will need an initial descent rate of -3000 ft/min to keep the speed from going below 300 KIAS. When it no longer requires 100% power on the remaining engine to sustain 300+ knots you can look for the nearest runway with 7000 ft or more to land. This sustainable power profile should occur around 60K ft and lower. Depending on your fuel load, you should be able to find a runway up to 250 miles away.

!!!! OVERSPEED WARNING !!!!
Overspeed conditions are very dangerous and you only have seconds to react. When flying near the mach limits very slight changes in weather can bounce you over the edge without warning. M3.2 normally provides a safe buffer zone with 100 knots between both overspeeds and stalls. Overspeeds are caused by very high (non-typical) pressure jumps. The best speed is to set the Mach to provide as close to 400 knots as is practical. 450 KEAS climb schedule is the most likely area where overspeed will occur as the IAS is just over 500. The KEAS hold button has the best capability to prevent overspeed on the climb. When flying using normal procedures and schedules, overspeeds are very unlikely.
OVER-SPEED PROCEDURE:
Disengage AB. Turning off reheat is the fastest way to react to overspeed but will cost you a TEB hit to restart. The result is a large power loss which helps slow down faster. If you don't want to use up TEB, a large manual pull back of the throttle will be necessary. If AB disengage is not enough, Disengage AT (shift-r) and idle the throttle. Avoid descent. Maintain altitude or climb will help prevent acceleration and increase your overspeed margin. Upon slowing to safe speed (do not slow below M 2.8) re-engage AB and/or AT (shift-r). Careful attention to the spike position will be necessary with large speed changes.

!!!! Electrical Power loss and Dead Stick Landing !!!!
Dead stick landing after the loss of two engines has been simulated as well as loss of generator power to the battery. Many successful dead stick landings have been made from 70K ft and up to 200 miles from a runway during testing. Longer distances are possible.
If the load on the battery is reduced to only necessary items, the battery will support the flight through landing.
If the battery fails, vital navigation equipment will remain functional:
Airspeed
Attitude
Altimeter
Vertical Speed
Radar Altimeter

------------------- END WARNINGS FAILURES AND PROCEDURES -------------------

Engine Spike:
This model is automatically controlled above Mach 1.6 and provides @ 1+% N1 improvement in efficiency at full retract (full flap deploy) into the engine. These are the settings should you descide to use the spike mode knobs in the Manual switch position (knobs facing right):
Subsonic to Mach 1.7 = retracted-spike fully extended (F5)
Mach 1.7 to Mach 2.2 = position 1 (1 tap F7) (25%)
Mach 2.2 to Mach 2.7 = position 2 (1 tap F7) (50%)
Mach 2.7 to Mach 3.2 = position 3 (1 tap F7) (75%)
Mach 3.2 = position 4 (1 tap F7 or F8 full engine retraction-flaps deploy) (100%)
NOTE: At speeds of Mach 1.6 or above, leaving the spike out of configuration for an extended time will cause temporary loss of the afterburner and of engine, requiring each to be restarted which costs two shots of TEB.

Cruise:
After switching the AP AT bug to Mach Hold at Mach 3.0, monitor the engine fuel rate. As the rate drops below 20K lbs/engine, slowly advance the mach hold to obtain the desired cruise speed for the remainder of the flight. Ideal fuel rates should be near 18K lbs/hr per engine. Be prepared to alter the cruise speed and altitude if changes in weather cause the plane to fly near the documented limits of 558 KIAS max or slower than 310 KEAS and/or max 427C intake temperature. You also want to avoid excessive fuel rates which might prevent you from getting the range you need for the mission.
There has been much discussion and speculation about the top speed capability. My opinion as to why we don't yet know the official top speed is because no one inside the program knows. Pilots flew the plane according to strict procedures controlled by the training or mission parameters which dictated fuel rates and altitudes to obtain maximum range between re-fueling assets and turn rates to prevent border or threat area incursions. The few times pilots got to push performance were in official speed record tests where clearly the plane was not being flown to its limits. Other high speed incidents occurred during missions where unexpected things happened. In some cases damage or loss resulted. In terms of raw specifications, the airframe clearly surpassed the design specification of Mach 3.33 or 500 KIAS. In reality, the limitation was not the power of the engine, but the danger of thermal damage beyond the intake temperature of 427C. The plane was never purposely flown above this limit. The limits set in this model provide a generous margin when operated in typical real-world flight profiles and weather.

Ideal Cruise Summary:
  • As close to 400 KIAS/360 KEAS as possible. Above 80K ft, lower airspeed is normal.
  • Above 310 KEAS
  • CIT below 427C
  • EGT below 830C
  • Fuel rates close to 18K lbs/engine (180 on readout)
  • Pitch below + 6
  • Pitch trim between 0 and -3

This is the most stable and low-maintenance stage of the flight.
Unless a weather condition causes one of the anomalies above, no action is necessary.
Your task is to manage speed and altitude to keep the pitch bug on the Artificial Horizon between the level and +5 indications. You will monitor the intake spike for proper movement. If fuel loading procedures were followed carefully, the fuel balance and attrition system will maintain controlled flight and balance within operational limits without intervention. The auto system will most closely track ideal when fueled to the medium range profile of 66K lbs on the ground.
Panel warnings will activate if COG or speed is out of limits for the flight profile. You can correct small imbalances with the fuel pump switch in the fuel panel.
Above Mach 3, a green annunciator panel indication will light showing the ideal COG range for the current weight. Ideal pitch trim for best fuel efficiency will be between zero and minus 3. Positive trim is normal early in the cruise at high fuel loads. Speeds of Mach 3.18+ where spike is fully retracked is best efficiency.

Keep this in mind:
- Higher, colder air provides higher mach indications and more fuel efficiency at a cost of reduced total engine power. Stalls are more likely.
- Lower, warmer air uses more fuel and heats the engine and surfaces. Over-speeds are more likely.

o Descent:
Note: High mach speeds procedures use KEAS (available in the main panel "Triple" gauge.) rather than IAS.

Descent Profile:
Descents are the most challenging part of flying the SR-71. A lot goes on in a short time and the performance constraints are tight. The pilot needs to be alert and have all the activities planed out ahead of time.

Note: The angle at which the air enters the engine at supersonic speeds is critical. Notice the engines are pitched down compared to the airframe so while the airframe is pitched up slightly at cruise, the engines remain close to on-axis to the air flow. When descending supersonic, there is a limit to how much off axis the air flow can get without stalling the engines.

The object is to approach the descent point as close to 400 KIAS as possible to make holding 365 KEAS in the descent as easy as possible. 365 KEAS is used because it keeps the plane well above 350 EAS below which unstarts are likely.
If you start the descent under 350 KIAS, you risk an unstart, so you must accellerate while at a shallow descent (no more then -1500 ft/min) until the plane is fast snough to engage EAS Hold safely.
If possible, try to obtain and lock in 365 KEAS hold just before or shortly after starting descent.
The easiest way to do this is when starting the decent and EAS is between 350 and 360, set your descent altitude target bug to a very low value (10 - 20K ft) and -4500 ft/min descent rate. Immediately, set the IAS bug to 365. This will give you time while the aircraft slowly accelerates to 365 EAS in the Triple gauge.
As the EAS display in the Triple gauge crosses 365 without blinking, immediately click the KEAS Hold button on the refuel panel above the Drag Chute Lever. If you miss the first time, increment/decrement the IAS bug more or less and wait for the display to cross 365 again. Once the hold is activated at the correct speed, set -5500 on the descent rate. With some practice, this will become easy.
Note: The EAS hold will not hold perfectly, but close enough to take the workload of managing the descent speed off the pilot. Most importantly, set properly, will prevent the EAS from going below critical 350.
KEAS HOLD WILL NOT WORK IN MACH MODE.
You cam now concentrate on managing the descent rate with two objectives:
1) Crossing various altitude targets at set distances from the landing or refueling target
2) Preventing the engine RPM from spooling below 6100
Note: Static temperatures colder than -69C will cause more difficulty keeping the RPM over 6100
Use the "friendly" descent target chart below and adjust descent rate (typically settings starting around -5500 to -2000 near the end.)
When the aircraft speed is below Mach 1.5 you can relax a bit as unstarts from descent rates are no longer possible.

Mach 0.90 is the standard cruise speed below Mach 1. Descent angle is typically between 1 degree at the start to near -7 degrees around Mach 1. AOA gauge should never go below zero degrees. Expect to drop out of AB near or below Mach 1 in a normal descent profile.
The engine spikes will start to extend soon after decent starts.
If decent rates exceed -6200 ft/min, Cabin PSI will display on the Annunciator. Reduce descent rate or switch pressure to 10K ft temporarily. 10K cabin pressure will increase H2O usage considerably.
Higher descent rates risk engine RPM falling below 6100 causing compressor stall. KEAS hold has both minimum and maximum hold values built into it to restrict overspeeds and stalls. The Master Warning light and RPM readout changing from white, to yelllow, to red indicates the pilot must take action to avoid minimum RPM stall.
DECSENT_PROFILE (83K)
The chart graphic above is converted into more FS friendly table below:

Distance
Land/Tanker

Altitude

Speed

395/308

90Kft

M3.2/365 KEAS

325/238

80

M3.2/365 KEAS

282/190

74

M3.2/365 KEAS

264/170

70

365 KEAS

220/116

60

365 KEAS

190/70

50

365 KEAS

163/40

40

400 KIAS

150/00

35

380 KIAS/M0.85

Under 150 miles

Set desc rate per desc calc gauge with approach target altitude set in AP alt.
Mote: Descentometer supplied with panel is very handy.

140/40

25

370 KIAS

(Edited for sr2012Updt1c):
Slowing below Mach 0.90 "CG HI" in yellow could display on the Annunciator. This is an awarness status and normally does not require action. Fuel Low indicates tanks 2 or 4 are below minimums which is unlikely to occur in a normal flight with proper ground fuel loading.
At 18K ft, set IAS bug to 340, and 16K ft, set 320 KIAS. At 14k ft AGL, set 280 KIAS. At 12K ft AGL, slow to 250 KIAS by setting IAS bug to initially to 240 then adjust upward to hold 250. Within 30 miles of landing slow to 220 KIAS minimum turn speed (10K lbs fuel.) Faster if heavier than 10K lbs total fuel.

o Terminal maneuvers and approach:
APP1 (21K)
PAT_APP (36K)
At light weight and slow, the model turns and changes speed rapidly. The pilot manual describes the sub-sonic handling as "adequate" and interviews with crew describe it this way in "SR-71 In Action":

"Subsonic, it feels like a big, heavy airplane, and you have to horse the stick around a bit to get the airplane to move."

Final approach should use speeds as suggested by weight and approach chart near the top of this document. Typical terminal speed for base turns is 220 KIAS minimum.)

Normal landing weight is 10K lbs and base turn should be made @16 miles (manual control) to 20 miles (AP/APP mode) and 220 KIAS. Higher fuel loads and or turbulence require higher speed.
When lined up reduce speed to 175 KIAS.
At max weight, decel to threshold speed should be made at least 9 miles out. 10K lbs fuel can decelerate in @7.5 miles. Threshold AOA is 9.5 degrees. Pitch is 10 degrees (not to exceed 14.)
Use shift-enter(FS9) Cntrol-Q(FSX) key sequence to lower the view to see the runway.
shift-backspace(FS9) Control-shift-Q(FSX) to pitch up or SPACE key(FS9) to recenter view to default.
Note: Many pilots remap the FSX shift-num-0 back to FS9's spacebar.
The Approach Auto-pilot will hold a steady glideslope with fuel weights up to 22,000 lbs down to around 600 feet.

Observe the AOA gauge to keep the threshold attitude under 10 degrees.
- Upon GS capture (when using AP APP mode) lower the gear passing - 5 ft/minute.
- Arm drag chute if there is little or no crosswind. An armed chute is indicated by the lever center changing from black to orange. If there is significant crosswind, operate the chute manually after the front wheels touch down.
- Between 500ft and 600ft take manual control (z key) of pitch, roll, and yaw while targeting the threshold with between 700-1000 ft/min descent.
- At apprx 150ft AGL flare to obtain minus 50ft/min or less and reduce throttle to idle at 10 ft after the key sequence control-r (to disengage AT control.)
On touchdown, chute will deploy on wheel contact WITH THROTTLE IDLE and AUTO-DEPLOY ENABLED.
Use stick back pressure when the nose begins to drop to front gear contact at 100 knots. On cross wind landing, deploy the chute manually after front wheel contact.
-Begin gradual breaking @65 knots ground speed. Anti Skid will prevent full breaking until speed passes below 12 knots. Expect siginificant breaking reduction on rain, ice and snow.
- Around 30 knots jettison drag chute (/) or increase engine speed slightly for a few moments. Increasing speed resets the auto-spoiler logic.
- Taxi to parking not exceeding 20 knots ground speed. Shut down engines using contrl-shift-F1, reducing throttle(s) below zero, or fuel panel switches.
Note: The high RPM of the engines may result in nearly constant breaking at low weight typical at landing. If breaking is a problem, one engine can be shut down. However, this causes a lot of steering to compensate for the induced yaw. It's a trade off.

Real world tanker descent (assumes M3.2 80Kft):
If slower than 422 KIAS, use Mach hold on initial descent. Otherwise use 422 KIAS.
-Start descent 325 miles from runway. Tanker is expected 100 miles this side of runway.
-Set descent alt (target) in AP for 29K ft.
-Gradually set initial dec rate to 4500.
-Crossing -2500 ft/min on VSI disengage AB.
-As air speed in mach hold approaches 425,
set 375 in the AT bug and adjust as needed to hold 420 - 425 until 40K ft. Use SPEED Warning gauge to help you keep it in check. Observe dec calc and adjust dec rate so calc and target runway distance match crossing 70K ft.
- At 70K ftset AP alt for 7000ft. Keep watch on the speed and adjust dec rate to keep the calc reading near or just over the distance to runway. Try to cross 50K ft with 180 miles to go.
- At 50K ft set target alt on the AP for 4,000ft. Adjust dec rate to cross 30K ft 150 miles from runway. Target crossing 40K at 163 miles. You should be - 6000 to -7000 ft./min by now.
- At 40K ft, set AT bug to obtain 400 KIAS and target crossing 30K by 150 miles.
- At 30K target crossing 25K by 140 miles. Set AT to obtain 370 KIAS.
- Within 100 miles of runway, adjust dec rate so calc display is 20 miles lower than distance to runway. Maintain this difference for remainder of approach to runway.
- At 30K ft, set AT bug to obtain 370 KIAS.
--- If using tanker, start rendezvous operations. ----
- At 25K ft, set target alt to runway approach altitude.
- @50 miles from runway and/or 14K ft, set AT bug
to obtain 300 KIAS crossing 12K ft.
- At 12K ft, set AT bug to obtain 250 KIAS by 10K ft.
- by 30 miles from runway, be slowed to 220 KIAS minimum maneuvering speed.

PROCEDURE SECTION COMPLETE


For those interested, a more complete explanation of the Fuel Balancing System:
When the standard loads of 45K, 55K, and 65K lbs fuel are used, the resulting CG should be between 20% and 22% while on the ground. By the end of taxi, CG around +-21% is normal.
There are two modes of CG control: Passive and Active.
Passive:
The position, quantity, and tank selection by normal FS attrition contributes largely to CG during climb and early cruise. Passive mode is indicated by zeros in the TGT: display and by the xFeed Open lamp lit bright in the Fuel Annunciator. If the pilot clicks on the xFeed Open lamp, the Auto CG system will be disabled. Note: There is no indication the CG system has been disabled if clicked on while already lit. If the lamp stays lit, the system was already in Passive Attrition mode and will now stay that way unless clicked again. It is not a good idea to click on this lamp unless necessary.
Active:
There are two active modes: Tank Selection and Tank Pumping.
Active is used largely to maintain high speed cruise CG, descent and landing CG. When in Active Mode, the xFeed Open lamp in the Fuel annunciator will not be lit and there will be a CG number displayed in the Fuel Panel "TGT:".
When the CG error is low but a correction necessary, individual tanks are selected which affect the balance in the desired direction. If the error grows beyond a certain limit (which could happen if the tank switching does not affect the CG fast enough) tanks 2 and 4 (centers) will pump fore and aft until the error is within tank selection or passive system effectiveness. Active pumping is indicated by the green lamps lit bright in on the Fuel Panel Pump switch. If these two tanks are full or near empty, the active pump is suppressed, but the active switching continues. Below 8000 pouds total fuel, all active correction is suppressed and passive only is in effect. Active mode is indicated by a target CG number in the "TGT:" display and the Fuel Annunciator xFeed Open not lit (unless the pilot clicked to over-ride.) The TGT percent is the CG the Active mode is trying to enforce an upper or lower limit on.

During the climb, tanks 1 and 4 deplete together providing a slow CG transfer to rear. At heavy weights, the rear tank 6 engages to prevent excessive rear CG for the weight. As speed increases above mach 3.05 and below 120K lbs gross weight, the CG will gradually move rearward based on speed to the maximum of 24.97%. If the pilot attemps to intervene for CG greater than 25%, the tank 6 will again engage to attempt to prevent this. Active pumping will engage if active switching is ineffective.
When tank 1 is empty, tank 2 will take over maintaining rear CG until it reaches the minimum of ~5400 lbs. This is just enough weight to provide some pilot intervention when landing near or below 10,000 lbs fuel weight. Your flight plan should always allow for landing as close to 10,000 lbs fuel as possible.
Below 30,000 lbs total fuel weight, CG is gradually lowered in favor of setting up descent and landing. Below 30K lbs fuel the influence on balance error is much reduced and the Annunciator no longer displays the suggested CG hint. This is not a problem.

As the aircraft approaches the terminal area and 21.5% CG, the remaining tank levels will work together to hold this CG as long as possible. Active CG control may not work well or at all with fuel levels under 8,000 lbs. Keep in mind 21.5% is the ideal CG for a 10,000 lbs fuel landing, so low CG and under 10K lbs fuel is not a big problem. It's quite easy to perform a good landing below this weight when proper AOA and speeds are used. The closer to 10,000 lbs fuel, the less the pilot has to be concerned with fuel balance maintenance and the landing is the easiest. Heavier weight also makes stopping a little easier.
Note: If the tanks are unbalanced left and right automated CG errors would occur. To prevent this, crossfeed is on for all tanks in passive mode, meaning there is no Left and Right engine isolation.
Passive mode is also engaged in an engine stall or unstart where the crossfeed will minimize L and R inbalance while only one engine is operating.


Some interesting facts:
The SR is composed of Titanium and Composite (plastic/carbon) materials. The landing gear is the largest piece of titanium ever forged in the world. The United States did not have enough Titanium to build the fleet and ironically, we bought the needed Titanium from Russia.

50 Blackbird airframes of various designations were built. The nose section can be removed and swapped with various configurations in radar and sensors and different shapes to the nose.

Speed/Altitude Limits: The highest speeds and altitudes claimed by verifyable sources are Mach 3.5 above which center window frame heats to the point of damaging the windows and a reported accidental altitude of 87,000 ft. The world record of 85,000 ft is considered the maximum safe altitude above which the engines start to become starved for oxygen. Conditions at which 85K ft and above can be obtained are not always available (ideal temperatures, pressure and weight.)

Costs to operate have been difficult to estimate due to the large variation in missions.
In my opinion, the most believable figure is $27,000 to $32,000 per hour exluding tankers, training, and various logistical support.

The A-12s were never called "blackbirds" and were referred to by their program name "CYGNUS" or "CYG".

The SR-71's fly at 33+ miles per minute (1,980 MPH/1,722+ knts) or 3,000 feet per second, faster than a 30-06 bullet.

Each SR-71 cost 33 million to build.

At Mach 3.0 the air flowing into the engine intake has to slow down to Mach .6 to prevent compressor stall. This is the equivalent of slowing from 2100 MPH to 600 MPH in 20 feet.

Aircraft skin temperature can reach 800+ deg F.

Refueling was not performed primarily because of high fuel loss from leakage, but to have a larger performance margin on take off in case of an engine flameout. At full fuel load above 35 ft, the minimum dyamic control speed with one engine on full military power is over 280 knots indicated!

Sonic Boom transmission time 75K ft: 1 min, 20 sec.

AB in Flight:
sr-71_AB

J58_AB_standT3 (12K)Full AB thrust test stand exhaust flame apprx 30ft long
producing 311 deg F temp and 150 knot winds 100 yards behind the engine.
Another jet engine is used to push hot, super sonic air into the intake. These shots were taken after closing the SR-71 program while burning off the last of the stored fuel.

J58_AB_standT1 (20K) J58_AB_standT2 (14K)

The cameras can photograph a golf ball on the green from 80,000 feet. They can survey 110,000 square miles of the Earth's surface per hour.

Ben Rich of Lockheed announced that the SR-71 had over 1,000 missile launches against it, but none successful. In 1981 a confirmed missle launch of two SA-2 missiles on an SR-71 occured near the Korean DMZ. The typical evasion technique was to keep flying straight so as not to slow down. Then existing communist computer technology was not fast enough to calculate an intercept from 16 miles away at closest point.

Pilots in a pressure suit can lose up to 5 pounds in a four hour flight.

Because of the sleek "hooded" appearance of the Blackbird caused by the chine, the Okinawans claimed it looked like a Habu cobra snake. Thus the nickname.
Apparently it's not normally aggressive to humans but has a nasty bite.
SR-71 Crew members are also called "Habus."
RODN is famous for the "Habu Hill" where friends, familly and local fanatics would gather to watch and photograph a take off. Pilots would rate each other on how large a crowd they could attract.

The SR-71 flew for 17 straight years (1972-1989) by the US Air Force without a loss of plane or crew. Of the 50 variants produced, 19 crashed with no loss of US Air Force crew.
One CIA crew was lost launching a drone in an M-21. The recon officer drowned in his chute on landing in water.
Another accident related to right engine unstart during turn at cruise causing a breakup and loss of the RSO during a Lockheed test flight.
The Seattle Museum of Flight in addition to the drone-mounted M-21 has the nose of a
crashed SR71 on landing at Kadena when the front gear collapsed in a storm.
The rest of the plane burned, RSO ejected and pilot rode it out until it stopped.
Visitors can sit in this cockpit.

Last Flight documented by NASA Dryden Edwards AFB web site:
"NASA's SR-71A served as a research platform from 1992 until its final flight flown by Smith and Meyer on Oct. 9, 1999, the last flight by any SR-71. It remains on display at NASA Dryden today. NASA's SR-71B served as both a research platform and for crew training and pilot proficiency until its final flight in October 1997."

478 total people have flown the Blackbirds. More people have climbed to the top of Mount Everest in that time.
Milestones:
- 29 October 1964: SR-71 prototype (#61-7950) delivered to Palmdale.
- 22 December 1964: First flight of the SR-71 with Lockheed test pilot Bob Gilliland at AF Plant #42.
- 5 February 1968: Lockheed ordered to destroy A-12, YF-12, and SR-71 tooling.
- 21 March 1968: First SR-71 (#61-7976) operational mission flown from Kadena Airbase over Vietnam.
- Sept 1, 1974: Beale to Farnborough World record flight.
- Sept 13, 1974: Mildenhall to Beale World record flight.
- 15 January 1982: SR-71B #61-7956 flies its 1,000th sortie.
- 22 November 1989: Air Force SR-71 program officially terminated.
- 21 January 1990: Last SR-71 (#61-7962) left Kadena AB.
- March 6, 1990: Last official Flight Palmdale to Dulles setting new world records delivering to Smithsonian Museum.
- Last flight of a military SR71 into Beale AFB for display: 1997 http://www.wvi.com/%7Esr71webmaster/sract%7E1.htm
- NASA used one of its two SR aircraft for research on the LASRE aerospike engine project as late as 1998:
http://www.nasa.gov/centers/dryden/history/pastprojects/SR71/Lasre/index.html

Program Info:(as of Jan 1990) Source: http://www.blackbirds.net/

* Total Flight Hours:...........53,490
* Total Mach 3+ Time:........11,675
* Total Sorties:.....................17,300
* Total Operational Sorties:....3,551
* Total Operational Hours:...11,008
*Total Air Refuelings..........25,862
* Total Crew Members:............284 (includes NASA and USAF Crews checked out in AC)
* Cumulative Hours by Crews:
o 300 Hours.....163
o 600 Hours.......69
o 900 Hours.......18
o 1000 Hours.......8
o 1392.7 Hours.....1

Some historic SR71 bases or refuel/repair/training sites:
EGUN Mildenhall England (main base)
EGUL Lakenheath England (temporary during Mildenhall runway repairs)
RODN Kadena Okinawa Japan (main base)
KBAB Beale Air Force Base Marysville California USA (main base)
KHIF Hill AFB Utah
KEDW Edwards Air Force Base California USA (Dryden)
KPMD Palmdale (Lockheed Martin Skunkworks Palmdale, CA)
KSKA Fairchild AFB Spokane WA USA (training.)
KOFF Offutt AFB Nebraska USA:
One brief landing was during the Sunday Mt. St. Helens eruption.
VTUD Udon Tailand
Utapao Tailand
Note: Most flights out of Palmdale were operated by CIA or Lockheed test pilots
and had differing procedures from the USAF.
KGSB Seymour Johnson AFB North Carolina (1973 Israeli War)
Other:
KNFL Fallon AFB Nevada (one emergency landing)
FJDG Diego Garcia Navy Base (one landing)
Carswell AFB, Texas (KNFW Frt Worth NAS?): One landing. Hydraulic pump failure with ground refueling from a parked tanker aircraft.
Area 51 "The Farm"

Paul R. Varn pvarn01@aol.com