What happened
On July 26, 2007, a Jabiru J 400 amateur-built aircraft, registered F-PSBY, was performing an experimental flight near the Bordeaux Yvrac aerodrome. The pilot was conducting the first flight of this specific aircraft. After performing several maneuvers in the vicinity of the airfield, the pilot entered a downwind pattern.
During the approach, as the pilot reduced airspeed and deployed the first stage of flaps, the elevator suddenly became ineffective. The pilot attempted to use the electric trim system, moving it to its full nose-up limit, but the aircraft continued to descend on a shallow slope. To manage the descent rate and prepare for landing, the pilot adjusted the engine power. However, after retracting the flaps to the landing configuration and reducing power, the aircraft struck the unpaved runway with a nose-down attitude, causing heavy damage to the airframe.
The investigation
The investigation focused on the mechanical failure of the elevator control system. The aircraft, which had been assembled by the flying club, featured a modification to the original design; the standard spring-loaded compensation system had been replaced with an electric trim system under a temporary permit.
The control linkage for the elevator utilized a Teleflex-type cable. Upon inspection of the control chain, investigators found that the end of the cable sheath was no longer held in position by its retaining clip. It was discovered that the original manufacturer-specified support for this clip was missing and had been replaced by a non-conforming part. The geometry of this substitute part failed to properly secure the sheath in place.