Gulfstream IV Crash Mystery Focuses on Mechanical Systems

Stephen Pope

Tuesday, June 17, 2014 at 07:02 PM ET

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Gulfstream IV's tire tracks

Key Takeaways:

Accident investigators are focusing on two perplexing clues in a fatal Gulfstream IV crash: contradictory data regarding the flap setting and a potential issue with the gust lock system.
Despite the gust lock handle being in the 'off' position, flight data indicates the elevator was deflected downward during taxi and takeoff, as if the gust lock was engaged.
A mechanical interlock should prevent the throttles from advancing beyond 6% with the gust lock engaged, yet the jet reached 165 knots before failing to lift off.
Crucially, flight data recorder information shows the pilots did not perform a control check before the takeoff roll, which could have identified the control problem.

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Accident investigators are focusing on two perplexing clues as they try to determine what caused the deadly crash of Gulfstream IV in Bedford, Massachusetts, on May 31 after the jet failed to lift off from the runway during what should have been a routine takeoff.

The first mystery concerns the GIV’s flaps. Investigators found the flap handle in the cockpit in the 10-degree detent, yet a review of flight data recorder information shows the flaps were set by the crew to 20 degrees before takeoff.