Investigation Summary
The investigation revealed a significant breakdown in cockpit discipline and a technical deficiency in the aircraft's design. The gust lock system, intended to protect control surfaces from wind damage while parked, featured a mechanical interlock designed to prevent the throttles from being advanced beyond taxi power if the lock was engaged. However, post-accident testing showed that the interlock on the G-IV allowed the throttles to be advanced significantly further than intended, enabling the aircraft to reach high speeds despite the locked controls. Data from the Quick Access Recorder (QAR) showed that the crew had a habitual pattern of non-compliance, failing to perform complete flight control checks in 98 percent of their previous 175 takeoffs. During the accident sequence, the pilot-in-command noted the controls were locked at rotation speed but did not immediately initiate maximum braking or reduce power, leading to a high-speed overrun into a ravine where the aircraft was destroyed by a post-crash fire.
Final Conclusions
The NTSB determined the probable cause was the flight crew's failure to perform a flight control check, their attempt to take off with the gust lock engaged, and their delayed execution of a rejected takeoff. Contributing factors included the crew's habitual noncompliance with checklists, Gulfstream's failure to ensure the gust lock/throttle interlock effectively prevented takeoff power, and the FAA's failure to detect this design inadequacy during certification.
Video Analysis
Runway Overrun During Rejected Takeoff in Bedford, MA 5/31/14 — NTSB animated reconstruction of the Gulfstream IV accident at Hanscom Field, showing the takeoff roll, the discovery of locked controls, and the delayed rejected takeoff sequence.
If playback is blocked, the owner has disabled embedding — use the link above.
Airframe & Maintenance
Crew Experience
Captain
Bauke 'Mike' De Vries
First Officer
James McDowell
Systems & Failure Modes
Gust Lock System
A mechanical system that locks the elevator, ailerons, and rudder to prevent wind damage while parked. It must be manually disengaged before flight.
Gust Lock/Throttle Interlock
A safety mechanism designed to physically restrict throttle movement to taxi power levels if the gust lock is engaged.
Quick Access Recorder (QAR)
A flight data recorder that provided investigators with the crew's historical performance, revealing a long-term habit of skipping checklists.
Interesting Facts
- 01The pilots had performed complete flight control checks on only 2 of their previous 176 flights.
- 02The aircraft reached a peak speed of approximately 165 knots (190 mph) during the takeoff roll.
- 03Post-accident testing of nine other G-IV aircraft showed the throttle interlock allowed 3 to 4 times more movement than the intended 6-degree limit.
- 04The aircraft was destroyed by a post-crash fire fueled by a full load of jet fuel.
- 05The NTSB found a pair of sunglasses inside the gust lock housing, though they were not cited as the primary cause of the failure to unlock.
Safety Actions & Advisories
FAA Airworthiness Directive
The FAA issued a directive requiring Gulfstream-IV operators to retrofit the gust lock system to ensure the throttle interlock functions as intended.
Gulfstream System Redesign
Gulfstream announced a redesign of the gust lock mechanism to prevent similar interlock failures.
Location
ACCIDENT SITE · Coordinates taken from the entered by an editor.