By Julian Avisenis
Contents:
1.
Introduction
2. Improvements in this version
3.
Features
4. Installation
A. Installation of the system as a replacement of
the default Microsoft GPS
B. Installation where no INS or GPS is already present
C. Note to developers
5. Manual programming
6. “Automatic” programming
7. Operation notes
8. The “fast track” to using the INS
1. Introduction
This Inertial Navigation System (INS) is especially intended to be of assistance to all those pilots who enjoy flying classic airliners, particularly on long flights. If correctly used, the INS should provide a more realistic means of long-haul navigation than the GPS, which postdates many of these classic aircraft. It may also be installed in more contemporary aircraft. All that is required is for the system to be accurately programmed with all the desired waypoints relevant to the desired flight. This may be done the hard way, the coordinates of each waypoint being sequentially entered, checked and saved. In the real world, this certainly takes up a lot of time. Most flight simmers don’t have the assistance of ground staff or a First Officer to help with this task. Such help would be welcome, and I have "simulated" this, allowing automatic programming of the INS directly from a valid flight plan. This version of the gauge is able to use flight plans in either FS2004 or FSX format. The unit is loosely based on the well-known Delco Carousels, but has extended waypoint capacity and is easier to operate, allowing long flights without having to monitor or adjust the unit.
2. Improvements in this version
· Installation of the gauge has been simplified.
· Icons are provided for you to use to open the window
which has the INS gauge.
· Simulated alignment function now added. As in the real world, the unit now requires to be aligned before use.
I have kept the process short, around 1 to 2 minutes, since I suspect few flight simmers want to wait much
longer than that!
· A limited "test" function has been added.
· Accuracy in following flight plans. No INS will consistently guide you exactly over every waypoint. Some are
more accurate than others. This simulated INS now has further improved accuracy, particularly with respect to
correction for
crosswinds.
·
More realistic display of North, South, East and West.
· Several new displayed parameters have been added to previous ones. These are explained later.
· The manual entry of coordinates is now easier. It was previously not that easy to see if you had entered a digit
or not, particularly if you were re-entering the same digit again! Instead of over-writing existing coordinates,
dashes now appear after entering N/S or E/W. Entry of a digit replaces each dash with the new digit as entry
progresses.
· Hopefully, the gauge is now more robust. It should continue to function even if incorrect procedures are
carried out. (Within reason!)
· A modified version of the gauge is also supplied. This should only be used if the original version will not work,
either because the autopilot of the particular aircraft is not based on the standard FS2004 or FSX autopilot, or
because some other unknown factor prevents the INS from functioning. Unfortunately, there are some aircraft
(particularly some commercial products) which will not allow this INS (and most others) to function at all.
3. Features
· Up to 99 waypoints may be entered and stored.
· Entry mistakes are easily corrected.
· Waypoints may be entered manually, or may be automatically converted and entered from a valid FSX or
FS2004 flight plan. The gauge will automatically determine which format of flight plan is being used and will
automatically extract and save the waypoint coordinates.
· Waypoints are saved to a WAYPOINTS.DAT file for future use.
· Waypoints may be changed or edited, even if they are “active”. This means you can edit a waypoint even while
you are flying towards it using the INS.
· Displays coordinates of current position.
· Displays coordinates of active waypoint.
· Displays ground speed in knots.
· Displays the current track angle of the aircraft in degrees.
· Displays current heading in degrees.
· Displays drift angle, i.e. the angle in degrees by which the aircraft heading differs from the current track angle.
This difference is mainly due to cross wind correction.
· Displays cross track distance, i.e. the distance in nautical miles by which the aircraft is off the desired track.
· Displays track angle error, i.e. the angle in degrees by which the current track differs from the desired one.
· Displays distance to active waypoint in nautical miles.
· Displays estimated time to active waypoint in hours and decimal minutes.
· Displays wind velocity and direction in knots and degrees.
· Displays the desired ("ideal") track to the active waypoint. Due to drift or course changes, this may be different
to the current track.
· Waypoint switching may be set to automatic or manual. See later for details.
· Automatic correction for crosswinds (within reason!) and other causes of drift. Accuracy is therefore quite high.
· Warning is given when the aircraft is approximately 2 minutes from the active waypoint.
· Warning is given if the unit is operating on battery rather than generator power.
· The alignment unit warns if the electrical power is inadequate.
· The unit is usually powered by engine number one’s generator, so it works in single or multi-engine aircraft.
· If no generator is available, battery power will suffice.
4. Installation
Please read and follow this carefully. Basic knowledge of windows operations and text editing is needed. I will not be held responsible for mistakes. There are two main scenarios concerning installation. Here are both in detail:
A. Installation of the system as a
replacement of the default Microsoft GPS:
· Copy the gauge (INS_V3.gau) into the “Gauges” folder which is in the main "Flight Simulator 9" or "Flight
Simulator X" folder. (Usually in "Microsoft Games", in "Program Files" in the case of FS2004, hopefully in your
main directory in the case of FSX. You may have to search!).
· Copy the GaugeSound.dll from the “Sound” folder to your main "Flight Simulator 9" or "Flight Simulator X" folder.
· Copy the “ins_v3” folder from the “Sound” folder to your "Flight Simulator 9" or "Flight Simulator X" “Sound”
folder.
· Open the "Aircraft" folder (in the main "Flight Simulator 9" folder or in "Airplanes" in "SimObjects" in the case
of FSX).
· Locate and open the aircraft folder of the particular aircraft which you wish to equip with the INS system.
·
Open the panel subfolder and locate the panel.cfg
file. Make a backup of it for safety or later uninstallation.
· Open the panel.cfg file using a text editor such as WordPad or Notepad.
· Change the GPS window entry in the [Window Titles] section near the top of the page to include the INS gauge
rather than the GPS gauge, e.g.:
before the addition:
[Window Titles]
window00=Main Panel
window01=Radio Stack
window02=GPS The default
FSX or FS2004 aircraft all use window02 for the GPS. See later for non-default
aircraft.
window03=Throttle Quadrant
window04=Compass
becomes:
[Window Titles]
window00=Main Panel
window01=Radio Stack
window02=INS
window03=Throttle Quadrant
window04=Compass
· Search for the Main Panel gauge entry. This is usually under [Window00], but not always. It will usually have
visible=1 in its parameters.
· First, change the default GPS Icon entry to the appropriate INSicon or INSicon1024 (the INSicon1024 icons are
larger) entry in your aircraft main panel. This will be needed to display or hide the INS gauge as required. Here is
an example from the end of a Main Panel section of a panel.cfg file:
before the addition:
gauge56=SimIcons!Avionics Icon, 72, 111
gauge57=SimIcons!GPS Icon,
86, 111 The default GPS icon.
becomes:
gauge56=SimIcons!Avionics Icon, 72, 111
gauge57=INS_V3!INSicon_02, 86, 111 Changed icon, in
this case it is INSIcon_02, appropriate
for opening window02 since it is window02 (in the window
titles above)
which will hold the INS.
· Now add the following line at the end, making sure that you number it one more than the last gauge number
that was already there, e.g.:
before the addition:
gauge56=SimIcons!Avionics Icon, 72, 111
gauge57=INS_V3!INSicon_02, 86, 111
becomes:
gauge56=SimIcons!Avionics Icon, 72, 111
gauge57=INS_V3!INSicon_02, 86, 111
The line which you have changed.
gauge58=INS_V3!INS_UPDATE, 12, 1,1,1 This adds an invisible but essential part of the gauge to the main panel.
Note the numbering as “gauge58” in this
case, i.e. one more than the last
entry number prior to the addition.
· Very important: If the aircraft concerned is not a default FSX or FS2004 aircraft, but is nevertheless fitted with the
default Microsoft GPS, the GPS may be in a window other than window02. You can still replace it with the INS
gauge, but you will need to ensure that you make the correct icon entry, e.g. don’t use INS_V3!INSicon_02 for a GPS
which
is in window 05. Use INS_V3!INSicon_05 instead.
· I have included these lines in the text file “example.txt” for convenience. Copy and paste them in
and change the xx to the appropriate gauge numbers and change the icon number if needed.
· If you find that you have to use the alternative version of the gauge (i.e. “HOLD” does not engage because the
autopilot coding is non-standard), merely use INS_V3!INS_ALT_UPDATE instead of INS_V3!INS_UPDATE.
· Now locate the GPS entry (it is always [Window02] for default aircraft. It may well vary for other aircraft)
and replace the lines below the [Window02] entry with the new entries (also in the “example.txt” file), e.g.:
before alteration:
[Window02] Don’t
change this.
size_mm=456,378 The default GPS size.
We will need to change this.
window_size=0.5 Window
size ratio. You can experiment here.
position=8 Experiment with different numbers here, from 0 to 8. Usually
7 or 8 will be best.
BACKGROUND_COLOR=0,0,0 No need to change this.
VISIBLE=0 If you change this to VISIBLE=1, this window will be visible
on loading the panel.
ident=GPS_PANEL The
default identity. We will change this to allow necessary resizing of the panel.
gauge00=fs9gps!gps_500,0,0 The gauge which
is to be replaced.
becomes:
[Window02] This remains unchanged.
size_mm=300,308 This is 50% larger than
the actual bitmap sizes. I find this a convenient size.
window_size=1.0 I find this to be a convenient window size.
position=8
BACKGROUND_COLOR=0,0,0
VISIBLE=0
ident=19000 Choose a
number between 10000 and 19999. Don’t duplicate an existing ident
number!
gauge00=INS_V3!INS,0,0,300,231 I find this to be a
convenient gauge size.
gauge01=INS_V3!ALIGN,0,231,300,77
I find this to
be a convenient gauge size.
· If you use the default ident (GPS_PANEL) the size may remain that of the default GPS. Not ideal because the
proportions of the panel will be wrong, but this may be acceptable to you There appears to be a restriction on
resizing the panel if the default identity is used in some aircraft, particularly the default ones.
· Once again, always use an ident between 10000 and 19999.
· Make sure you don’t use a number that is already in use in the same panel!
· Save the changes and exit.
· All done!
B. Installation where no INS or GPS is already
present:
· This is not as easy as replacing a default GPS with the INS, and some trial and error will be needed.
· Copy the gauge (INS_V3.gau) into the “Gauges” folder which is in the main "Flight Simulator 9" or "Flight
Simulator X" folder. (Usually in "Microsoft Games", in "Program Files" in the case of FS2004, hopefully in your
main directory in the case of FSX. You may have to search!).
· Copy the GaugeSound.dll from the “Sound” folder to your main "Flight Simulator 9" or "Flight Simulator X" folder.
· Copy the “ins_v3” folder from the “Sound” folder to your "Flight Simulator 9" or "Flight Simulator X" “Sound”
folder.
· Open the "Aircraft" folder (in the main "Flight Simulator 9" folder or in "Airplanes" in "SimObjects" in the case
of FSX).
· Locate and open the aircraft folder of the particular aircraft which you wish to equip with the INS system.
· Open the panel subfolder and locate the panel.cfg file. Make a backup of it for safety/uninstallation.
· Open the panel.cfg file using a text editor such as WordPad or Notepad.
· Add a new window entry to the [Window Titles] section near the top of the page (provided in the “example.txt”
file), e.g.:
before the addition:
[Window Titles]
window00=Main Panel
window01=Radio Stack
window02=Throttle Quadrant
window03=Compass
becomes:
[Window Titles]
window00=Main Panel
window01=Radio Stack
window02=Throttle Quadrant
window03=Compass
window04=INS This adds a new window for the INS to occupy. Note the numbering as “window04”, i.e. one more than
the last entry number prior to the addition.
·
Now search for the Main Panel gauge entry (usually under [Window00], but not always. It will usually have visible=1
in its parameters).
· First, add the appropriate INSicon or INSicon1024 (the INSicon1024 icons are larger) entry to your aircraft main
panel. This will be needed to display or hide the INS gauge as required. (Otherwise you have to display/hide it by
pressing Shift-5 on your keyboard in this case, or Shift-(window number+1) in general). It is likely that the panel
already has some SimIcons or SimIcons1024 as shown in this example from the end of a Main Panel section of a
panel.cfg file:
gauge21=SimIcons1024!Electrical Panel Icon,
716, 748
gauge22=SimIcons1024!Other Controls
Icon, 741, 748
gauge23=SimIcons1024!Clock
Icon,
766, 748
Note the columns of numbers. The first gives the position of each SimIcon in pixels from the left hand side of
the panel. In this case they are 25 pixels apart. The second gives the position of each SimIcon in pixels from
the top of the panel. In this case they are in a row. Add
the INS icon as follows:
gauge21=SimIcons1024!Electrical Panel Icon,
716, 748
gauge22=SimIcons1024!Other Controls
Icon, 741, 748
gauge23=SimIcons1024!Clock
Icon,
766, 748
gauge24=INS_V3!INSicon1024_04,
791, 748 Added icon, in this case it is
INSicon1024_04,
appropriate for opening window04 as in the
window titles
above.
· I have included this line in the text file “example.txt” for convenience. Copy and paste it in and change the xx to
the appropriate
gauge number and enter the appropriate icon number.
· In this example I have placed the INS icon in line with the others, 748 pixels from the top of the panel and 25
pixels to the right of its neighbour (766+25=791). You may have to experiment to find the best position. If there
are no icons on the panel at all, even more experimentation and adjustment will be needed to find a good position
for the icon.
· Now add the following line at the end, making sure that you number it one more than the last gauge number
that was already there, e.g.:
before the addition:
gauge21=SimIcons1024!Electrical Panel Icon,
716, 748
gauge22=SimIcons1024!Other Controls
Icon, 741, 748
gauge23=SimIcons1024!Clock
Icon,
766, 748
gauge24=INS_V3!INSicon1024_04, 791, 748 The line which you have
already added.
becomes:
gauge21=SimIcons1024!Electrical Panel Icon,
716, 748
gauge22=SimIcons1024!Other Controls
Icon, 741, 748
gauge23=SimIcons1024!Clock
Icon,
766, 748
gauge24=INS_V3!INSicon1024_04,
791, 748 Already added line.
gauge25=INS_V3!INS_UPDATE,
12,1,1,1 This adds an invisible but
essential part of the gauge to
the main panel. Note the numbering as "gauge25" in
this
case, i.e. one more than the last entry number
prior to
the
addition.
· I have included these lines in the text file “example.txt” for convenience. Copy and paste them in and change
each xx to the appropriate number.
· If you find that you have to use the alternative version of the gauge (i.e. “HOLD” does not engage because the
autopilot coding is non-standard), merely use INS_V3!INS_ALT_UPDATE instead of INS_V3!INS_UPDATE.
· Finally, add the INS and ALIGN gauge entries (provided in the “example.txt” file) after the last of the [Windowxx]
entries (before any [Fixed Windowxx] or other entries such as [Vcockpitxx], [Color], etc.), e.g.:
[Window04] Make sure the number corresponds to the [Window Titles] number (see above), 04 in this case.
size_mm=300,308 This is 50% larger
than the actual bitmap sizes. I find this easiest to use.
window_size=1.0 I find this to be a convenient window size. You can experiment.
position=8 Experiment
with different numbers here, from 0 to 8. Usually 7 or 8 will be
best.
BACKGROUND_COLOR=0,0,0
VISIBLE=0 If you change this to VISIBLE=1, this window will be visible on loading the panel.
ident=19000 Choose a
number between 10000 and 19999. Don’t duplicate an existing ident
number!
gauge00=INS_V3!INS,0,0,300,231
I find this
to be a convenient gauge size.
gauge01=INS_V3!ALIGN,0,231,300,77 I find this to be a convenient gauge size.
· You can experiment with different gauge and window sizes.
· Save the changes and exit.
· Done!
C. Note to developers:
· Should you decide to use this gauge in a panel, you are free to install it as you like. Please note that it has
three subgauges. The alignment unit is essential to operation. UPDATE must always be on a panel which
is permanently open, usually the main panel, or else the gauge will not work. INS and ALIGN can go on any
panel.
5. Manual programming
Start by running FS2004 or FSX. Create a flight plan using
the flight planner which is part of FS2004 or FSX. If you don't know how to do
this, it is well explained in the "
Enter the waypoints as follows:
· Turn the selector on the alignment unit to "STBY" to switch the INS system on.
· Select "WAYPT", or waypoint mode, using the mode selection knob at the left of the instrument.
· Push "SET". The "SET" button should illuminate.
· If the INS already contains waypoints, you will now be overwriting them.
· Enter the coordinates of the first waypoint (00), which must be your current position. If necessary, press
Shift + Z on your keyboard to see where you are! Enter very carefully (easy to make mistakes!) using the
keypad at the lower right corner of the instrument. The order is vital: first "N" or "S" for North or South, then
the digits in order, not forgetting zeros. (Example: S0092102. This is South 9 degrees and 21.02 minutes.)
Continue by entering "W" or "E" and the required digits. If you make a mistake, use the "CLEAR" key to
erase one digit at a time.
· Please note that some keys have both a letter and a number. Don’t worry about this. Selection of letter or
number is automatic as appropriate.
· Push "INSERT" to save, but only once you have checked your entry.
· Click on the white digits below the "HOLD" and "SET" buttons to move to the first waypoint (01), push "SET"
again and enter and save the next pair of coordinates as above. Continue the process until all waypoints are
entered.
· If you discover a mistake once you have saved a waypoint, you will have to enter that whole waypoint again.
(But fortunately, not the whole plan!)
· Please note that the "WYPT CHG" key and the "LAST WPT" key are used to determine which waypoint is to be
the active one, they play no part in entering the waypoints.
· Pressing the " WYPT CHG" key advances the active waypoint by one for each press.
· Pressing the "LAST WPT" key followed by "WYPT CHG" will return you to the first waypoint which then becomes
the active waypoint. (Simply, "WYPT CHG" moves ahead one waypoint at a time, "LAST WPT"
followed by "WYPT CHG" takes you back to the beginning. So, you can advance one waypoint at a time, but
can only go back to the first waypoint.)
6. “Automatic” programming
As above, you need a saved flight plan created with the aid of a flight
planner which is able to save a flight plan in FS2004 or FSX format. Again, if
you don't know how to do this, it is well explained in the "
·
Minimize or exit FS2004 or FSX.
·
For FS2004, open your "My Documents" folder and then open the
"Flight Simulator Files" subfolder. For FSX,
the plan is likely to be in "Flight Simulator X Files"
in "My Documents". Locate the desired saved plan. It is
always a ".PLN" file.
· COPY and
paste (not cut and paste!) the plan to the main "Flight Simulator
9" or "Flight Simulator X" folder.
(Usually in "Microsoft Games", in "Program
Files" in the case of FS2004, hopefully in your main directory in the
case of FSX).
· Rename the plan "PLAN" (in upper case as shown, but without the quotation marks). Don't change the ".PLN"
extension, or the plan will be unusable.
· Open the plan using WordPad. Be sure to tick the "Always use the selected program to open this type of file"
box for future ease of use. Ensure that the first waypoint (waypoint.1 in FS2004, the first <Worldposition> line
in FSX) is the first waypoint , and not your point of departure or the reference coordinates for the departure
airport. If it is the departure point or the airport reference coordinates, simply delete that entire line and save.
Later, your first waypoint (not starting position) will automatically be saved in the INS unit as waypoint 01.
Waypoint 00 will hold the current or starting position. All of this is automatic.
·
Please note that FS2004 and FSX use different formats for coordinates!
FS2004 uses degrees and decimal
minutes. FSX uses degrees, minutes and decimal seconds. This INS
gauge uses the FS2004 format. Third party
planners may use either or both formats. You may be able to use an FSX-generated .PLN plan for an FS2004
flight (and vice-versa) by automatic conversion with this INS gauge, but exact positions may differ by a few
metres. The FSX
"world" is not exactly the same as the FS2004
"world".
· Back in FS2004 or FSX, load the desired aircraft and turn the selector on the alignment unit to "STBY" to switch
the
INS system on.
· Select
"WAYPT", or waypoint mode, using the mode selection knob at the left
of the instrument.
· Double
click on the top left screw on the faceplate of the INS unit. Voila! The plan is
entered. Double check that
the first two coordinates are the ones you really want, i.e. 00 is the starting position and 01 the first true
waypoint.
· The
coordinates will automatically be saved in the main "Flight Simulator
9"or "FSX" folder in the correct format
as a "WAYPOINTS.DAT" file. The "PLAN.PLN" file may
therefore be deleted if you wish. I often save the
"WAYPOINTS.DAT" files of "favourite" flight plans in a separate folder (with saved maps, charts, weather or
".WX" files, the .PLN file etc.) for backup and later use. When required, simply copy the appropriate
"WAYPOINTS.DAT" file to the main "Flight Simulator 9" or "FSX" folder (overwriting any previous one).
Occasionally, I may have both a "WAYPOINTS.DAT" file for the outbound flight and a "PLAN.PLN" for the
return in the "Flight Simulator 9" or "FSX" folder at the same time. The INS will always use the
"WAYPOINTS.DAT" file. When I start the return trip I simply double click on that "active" screw as above and
the "WAYPOINTS.DAT" file will be overwritten with the new coordinates for the return flight. Theoretically, in
this way, you could have up to 198 waypoints available for the same session! However if you find that you are
doing this, you are probably in urgent need of
psychotherapy. J J
7. Operation notes
Here are some more detailed (and important!) explanations concerning the functions of the buttons and selectors of the INS unit:
"WAYPT"
position selected, "SET" not lit. "WAYPT" position
selected, "SET" lit, "S" entered.
The mode selector in the "WAYPT" position displays the coordinates of the selected waypoint in standard format, i.e. degrees and decimal minutes. If the selector is in the "WAYPT" position and "SET" is not illuminated, the active waypoint indicated in the "TO" window will be displayed. If the selector is in the "WAYPT" position and "SET" is illuminated, the waypoint displayed is the one indicated in the window just below the "HOLD" and "SET" buttons and not the one indicated in the "TO" window. This dual function allows one to enter or alter any coordinate in the list while navigating toward another. In the illustration above right, waypoint 07 is being edited while the aircraft is flying between waypoint 02 and waypoint 03. It is also possible to edit the active waypoint while heading toward it, i.e. the "TO" display and the waypoint number selector will then indicate the same waypoint number.
In "POS" the coordinates of the current aircraft position are displayed, also in degrees and decimal minutes.
"DIS/TIME" gives the distance in nautical miles (left quartz display) to the selected or active waypoint and an estimated time in hours and decimal minutes (right quartz display) to that waypoint.
"WIND" indicates wind direction in degrees (left quartz display) and velocity in knots (right quartz display).
"DSRTK/STS" gives the desired track in degrees to the active waypoint (left quartz display) and the system status (right quartz display). Status "0" indicates that alignment has not commenced. Selecting "ALIGN" on the alignment unit will cause the status to jump to "9", after which it will gradually decrease during the alignment process until "1" is reached. At "5" the green light on the alignment unit should illuminate, indicating successful alignment. You may select "NAV" on the alignment unit once "5" or less is displayed.
"XTK/TKE" indicates the distance in nautical miles by which the aircraft has deviated left or right from the desired track (left quartz display) and the angle in degrees to the left or right by which the track of the aircraft differs from the desired track (right quartz display). Note that this has nothing to do with the actual heading of the aircraft.
"HDG/DA" displays the heading in degrees (left quartz display) to the selected waypoint. Please note that the heading will vary slightly during the flight between waypoints, depending on drift due to winds aloft and other factors. Drift angle is the angle in degrees by which the aircraft heading differs from the current track angle (right quartz display). This difference is mainly due to cross wind correction. The value is preceded by "L" or "R" indicating whether the aircraft heading is to the left or the right of the track heading.
"TK/GS" gives the angle of the current track of the aircraft in degrees (left quartz display) and the speed of the aircraft over the ground below in knots (right quartz display).
The "WYPT CHG" button may be used to "skip ahead" at any stage of the flight, even in "AUTO" mode. The aircraft will change course and head for the new waypoint. Waypoint numbers may be advanced by left-clicking the "WYPT CHG" button or by using the mouse wheel while hovering over the button.
The "LAST WPT" button will illuminate if pressed. Pressing the "WYPT CHG" button thereafter will extinguish the "LAST WPT" button and will take you back to the first waypoint (usually your starting position). The aircraft will change course and head for the first waypoint. It is unlikely that you will want to do this, but this function may be used to go back to the first waypoint and then, using the "WYPT CHG" button, to one of your earlier waypoints if so desired. It is best to do this with the unit disengaged and the aircraft maintaining your last heading.
The "HOLD" button engages/disengages the INS. It will only engage the INS if the autopilot is on and in heading mode. This is most important. The unit will not operate in any other autopilot mode unless you use the version of the gauge provided which specifically allows the unit to operate without heading mode engaged. This version should only be used if you are attempting to use the INS in a commercial or other third party aircraft which does not use the standard autopilot coding. Even then, I cannot guarantee that the unit will work in such a case, particularly since some commercial aircraft are "tied" to another specific third party INS or GPS. In one or two such instances, this INS may still be made to work if the one "tied" to the aircraft is installed but not used. The "HOLD" button will illuminate when the INS is successfully engaged. Please note that if you should switch the autopilot off or disengage it from heading mode, the INS will automatically and immediately disengage. (This may not happen if you use the version which does not require heading mode to be engaged. It is really difficult to make allowances for all possible third party aircraft.) It is possible to plan the last stages of a flight so that the last leg crosses/intercepts an ILS signal at an appropriate angle (usually about 25 to 30 degrees) and suitably far out from the runway threshold (usually 15 nm or more). Simply switch the autopilot to approach mode just before the intercept, the INS will automatically disengage and the ILS localiser and glide slope should be captured as usual.
The “SET” button will illuminate when pushed. Pushing it a second time will extinguish it. Waypoints may be entered while it is illuminated and the unit is in waypoint mode (selector on “WAYPT”).
The “CLEAR” button will erase one character at time while a waypoint is being entered.
Pressing the “INSERT” button will store waypoints once entered.
The number and letter buttons are self-explanatory. Please note that letters (N or S and E or W) are entered first on each quartz display and subsequent presses will automatically enter the numbers associated with those buttons rather than the letters.
The remaining selector in the "AUTO" position will cause the INS to sequentially and automatically advance through all the waypoints. If "MAN" is selected, the waypoints have to be manually advanced using the "WYPT CHG" button. In this mode, the pilot has to judge the best time to switch to the next waypoint, allowing for the rate of turn of the aircraft. This will vary under different conditions. This facility may be useful if waypoints are relatively close together, but obviously, while navigating in this manner, the unit will need your constant attention. Please note that in this mode the INS will disengage if you do not advance the waypoint before you are within 0.5 nautical miles of the active waypoint. If this happens you will have to push the “HOLD” button to re-engage the unit.
Pressing the centre of the above selector will illuminate all LCDs and buttons equipped with lights as a “test” of the displays and the button lights.
The "BAT" light indicates that battery rather than generator power is being used. It will extinguish once the generators are "on line". This unit operates off battery power or generator number 1. (For developers: it uses the MASTER_BATTERY and GENERAL_ENGINE1_GENERATOR_ACTIVE token variables.)
The "ALERT" light will automatically illuminate when the aircraft is approximately 2 minutes from the selected waypoint.
Here is a description of the functions of the alignment unit:
The mode selector in the "OFF" position implies that neither the alignment unit nor the INS unit itself has power.
In "STBY" both are powered. If the power source is inadequate, the red "BAT" light will illuminate.
In the "ALIGN" position, the alignment process will commence, provided the current position has been entered as waypoint 00 and the aircraft has not been moved since the entry was made. (Relatively minimal movement such as a short pushback may still allow alignment to proceed.) Progress may be monitored by selecting "DSRTK/STS" on the INS unit. Initial alignment status is displayed as the number 9 in the right quartz display of the INS unit. This number will gradually decrease as alignment takes place. The system is aligned once 5 or less is displayed.
"NAV" should be selected once the system is aligned. It is then ready for use.
Once aligned, the green "READY" light will illuminate. On selecting "NAV" it will be extinguished.
8. The “fast track” to using the INS
By now you have enough information to be able to use the INS. In summary, for the automatic method of use:
· Create a valid FS2004 or FSX flight plan. This will be a “.PLN” file, usually stored in the "Flight Simulator 9"
subfolder in the “My Documents” folder of your computer, hopefully in "Flight Simulator X Files" in "My
Documents" in the case of FSX).
· Copy and paste this plan into the main "Flight Simulator 9" or "FSX" folder.
· Rename the plan “PLAN” (without quotation marks). Be sure not to lose the “.PLN” extension.
· Open the plan using WordPad. Check that the first waypoint (waypoint.1 in FS2004, the first <Worldposition>
line in FSX) is the first waypoint, and not your point of departure or the reference coordinates of the airport.
Just delete the whole line if it is and save.
· Back in FS2004 or FSX, turn the selector on the alignment unit to "STBY" to switch the INS system on. (Ensure
that you have battery or generator power first!) Double click on the upper left screw on the faceplate of the
INS instrument. The plan should now be automatically converted and entered.
· Select "DSRTK/STS" on the INS unit to view instrument status.
· Advance the selector on the alignment unit to "ALIGN". The aircraft must be stationary throughout the process.
· Once the status has counted down to 5 or less (the "READY" light will illuminate), advance the alignment unit
selector to "NAV".
· Select “WAYPT” on the INS unit and press "WYPT CHG" so that waypoint 00 is displayed in the "FROM" window
and waypoint 01 is displayed in the "TO" window.
· Check that the distance to waypoint 01 is what you expect by selecting "DIS/TIME" on the INS unit.
· You are now ready for takeoff. Obviously, the INS can only be used once airborne.
· In order to engage the INS, first engage the autopilot and set it to heading mode.
· Engage the INS by pressing the "HOLD" button on the INS panel. Make sure the "HOLD" button illuminates.
· The aircraft should now follow the programmed route.
· Disengage the INS by pressing "HOLD", disengaging heading mode on the autopilot or switching the autopilot
off.
Manual use is similar to the above, skipping the plan conversion process. Just switch on and enter the coordinates, making sure the first set represents the current aircraft position (Press Shift + Z on your computer keyboard). Then align the unit and continue as above. It is possible to align any time after entering the starting position as long as the aircraft has not moved. The remaining coordinates may be entered later.
It is also possible to use this unit for flights saved in the airborne state. Alignment can be achieved in such cases as follows:
· Enter slew mode after loading the flight, i.e. while flying (usually by pressing “Y” on your keyboard). This
effectively creates a motionless situation so that alignment can proceed as usual:
· Switch the unit on to "STBY".
· Select waypoint 00 in the window above the word "WAYPT".
· Now select "WAYPT", or waypoint mode, using the mode selection knob at the left of the instrument.
· Push "SET". The "SET" button should illuminate as usual.
· Enter the current position (press Shift + Z on your keyboard to see this) as the first or starting waypoint (00).
· Check your entry by selecting "POS".
· Push "INSERT" to save.
· Select "DSRTK/STS" on the INS unit to view instrument status.
· Advance the selector on the alignment unit to "ALIGN".
· If this should fail, switch the unit off and then on and to "ALIGN" again.
· Select “NAV” once aligned, exit slew mode and continue the flight.