FA7X, en-route, north east of Kuala Lumpur Malaysia, 2011

FA7X, en-route, north east of Kuala Lumpur Malaysia, 2011

Summary

On 24 May 2011, a sudden uncommanded maximum upward deflection of the trimmable horizontal stabiliser occurred to a descending Dassault Falcon 7X. Automatic opposite elevator movement did not resolve the situation and an upset lasting just over 2½ minutes followed with a 9,500 feet climb at up to 41° pitch and a speed drop to 125KCAS. Only autonomous return of normal pitch response ended the control difficulty. The remainder of the flight was without further event. A single suddenly defective component with no effective crew response available and not anticipated during type certification was found to have caused the runaway.

Description

On 24 May 2011, the crew of a Dassault Falcon 7X (HB-JFN) being operated by Swiss-based Jet Link AG on a non-revenue positioning flight from Nuremberg, Germany to the Kuala Lumpur business airport at Subang in night VMC had to suddenly respond to a pitch trim runaway for which there was no procedural response. A short upset involving extreme pitch up and speed loss almost to the point of a stall followed before normal pitch control returned after less than 3 minutes with no recurrence thereafter. None of the three crew on board were injured and the aircraft was undamaged.

Investigation

The event occurred in Malaysian airspace but the Investigation was delegated to the French BEA. The aircraft was fitted with two identical flight recorders which combined the function of 25 hour FDR and a 2 hour CVR. Data were successfully downloaded from the FDR units within these recorders but as neither recorder had been electrically isolated after the flight, the voice recording data had been overwritten.

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