Gulfstream G-IV Bedford NTSB Hearing
Gulfstream G-IV Bedford NTSB HearingCredit: NTSB (National Transportation Safety Board)
Photo: Courtesy of Mass State Police
Full ERA14MA271 Docket available at: https://go.usa.gov/3DBuQ
Probable Cause
The NTSB determines that the probable cause of this accident was the flight crewmembers’ failure to perform the flight control check before takeoff, their attempt to take off with the gust lock system engaged, and their delayed execution of a rejected takeoff after they became aware that the controls were locked. Contributing to the accident were the flight crew’s habitual noncompliance with checklists, Gulfstream Aerospace Corporation’s failure to ensure that the G-IV gust lock/throttle lever interlock system would prevent an attempted takeoff with the gust lock engaged, and the Federal Aviation Administration’s failure to detect this inadequacy during the G-IV’s certification.
Recommendations
As a result of this investigation, the NTSB makes safety recommendations to the FAA, the International Business Aviation Council, and the National Business Aviation Association:
To the Federal Aviation Administration:
1. Identify nonfrangible structures outside of a runway safety area during annual 14 Code of Federal Regulations Part 139 inspections and place increased emphasis on replacing nonfrangible fittings of any objects along the extended runway centerline up to the perimeter fence with frangible fittings, wherever feasible, during the next routine maintenance cycle.
2. After Gulfstream Aerospace Corporation develops a modification of the G-IV gust lock/throttle lever interlock, require that the gust lock system on all existing G-IV airplanes be retrofitted to comply with the certification requirement that the gust lock physically limit the operation of the airplane so that the pilot receives an unmistakable warning at the start of takeoff.
3. Develop and issue guidance on the appropriate use and limitations of the review of engineering drawings in a design review performed as a means of showing compliance with certification regulations.
Findings
1. The flight crew was qualified to operate the airplane, and the use of alcohol or drugs, fatigue, and medical conditions were not factors in the flight crew’s performance.
2. The flight crew failed to disengage the gust lock system as called for in the Starting Engines checklist and failed to conduct a flight control check as called for in the After Starting Engines checklist, during which the crewmembers would have detected that the gust lock system was engaged.
3. Given that the flight crew neglected to perform complete flight control checks before 98% of the crewmembers’ previous 175 takeoffs in the airplane, the flight crew’s omission of a flight control check before the accident takeoff indicates intentional, habitual noncompliance with standard operating procedures.
4. About the time that the airplane reached a speed of 150 knots, one of the pilots activated the flight power shutoff valve, likely in an attempt to unlock the flight controls, but this action
was ineffective because high aerodynamic loads on the elevator were likely impeding gust lock hook release.
5. The flight crew delayed initiating a rejected takeoff until the accident was unavoidable; this delay likely resulted from surprise, the unsuccessful attempt to resolve the problem through use of the flight power shutoff valve, and ineffective communication.
6. The flight crewmembers’ lack of adherence to industry best practices involving the execution of normal checklists eliminated the opportunity for them to recognize that the gust lock handle was in the ON position and delayed their detection of this error.
7. Independent safety audits performed by an industry safety organization did not adequately encourage best practices for the execution of normal checklists.
8. An analysis of Corporate Flight Operational Quality Assurance Centerline data specifically evaluating the rate of noncompliance with flight control checks before takeoff could help define the scope of procedural noncompliance in business aviation and guide the development of strategies to address it. (Subject to change pending further review.)
