position indicating that the elevator is free. If this does not occur by 80 knots, the takeoff should be aborted.’


Instead it appears likely that the crew tried to work around the problem. Investigators spoke to one of the pilots who flew the aircraft to cover for crew holidays. The relief pilot named no names, but told of a practice used when the gust lock was not disengaged before starting the engines. Some pilots would use the flight power shut-off handle to relieve hydraulic pressure momentarily on the flight controls. This allowed the gust lock to be removed without shutting down the engines.


This is what the NTSB concluded had happened, based on non-activation of the spoilers, and deactivation of the hydraulic yaw damper. Its testing found the work-around to be effective when the aircraft was parked or taxiing at low speed, but unlikely to be effective at take-off speeds due to aerodynamic loading on the elevator. Under these conditions the gust lock handle would go to an intermediate position with the gust lock hooks remaining engaged. When the load was removed, the gust lock handle sprang to the off position. To perceive this limitation would require an ‘engineering-level understanding of the flight control system,’ the NTSB said.


The investigation noted ‘missteps during the emergency response (involving water resupply procedures, firefighter knowledge of the airport and Gulfstream IV main entry door operation procedures)’ but said the outcome would likely have been the same had these not occurred.


A design that failed to do its task had met a crew that failed to do theirs. They made an omission, as all human beings do sooner or later, because they were relying on skill instead of procedure. They also missed several warnings, although two of these—the rudder light and the yoke—are undoubtedly much clearer in hindsight. It’s more difficult to explain away ignoring a jammed throttle. Then when the problem became clear, they tried to work around it instead of stopping, which the investigation found they would have been able to do, even after waiting another 11 seconds from the first call of ‘steer lock is on’.


NTSB board member, Robert Sumwalt, added an appendix with a bitter, but true, remark. ‘You can fool the auditors, but never fool yourself.’


NTSB Analysis


... In the meantime, at least one lesson is clear. Checklists are important regardless of our familiarity with the equipment we are operating.


And we should never forget the basics before taking the runway. Checking for full movement of flight controls before pushing the throttles forward is every bit as important as checking that the wheels are down on short final.


CRM 2, TEM, Fatigue 14


Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29