What happened
On 13 March 2003, a Cesslam 310R, registration N234SA, was performing a private flight returning to Nottingham Airport. Following a landing on Runway 09 that the pilot described as firm, the aircraft began a right-hand turn to exit the runway onto a taxiway. During this maneuver, the left main landing gear collapsed. This caused the left propeller and left wing to strike the runway surface, resulting in damage to the left wing tip, the horizontal tail, and the left propeller. There were no fatalities and no injuries to the pilot or the two passengers on board.
The investigation
The AAIB examined the aircraft and the landing gear mechanism. The investigation focused on the downlock link, which supports the left gear side brace. Investigators found that the downlock link had failed due to a bending overload. The pivot bolt within the link had also been bent, and the associated bush had been deformed.
Records showed that the aircraft had previously undergone significant repair work following a wheels-up landing in 1995. While the landing gear doors had been repaired, the investigation noted that the threaded stud in the downlock link was adjusted to nearly its minimum length. This adjustment provided minimal movement for the side brace into its over-centre position. Calculations regarding the aircraft's landing performance suggested that the pilot's reported groundspeed of 10 kt was achievable, though a witness estimated a higher speed. However, the investigation concluded that a properly rigged gear should have withstood the side loads of the turn.
Findings
- The failure of the downlock link was caused by a bending overload.
- The incorrectly rigged left main landing gear system likely allowed the side brace to move out of its over-centre position.
- The side load experienced during the turn, combined with the lack of sufficient movement in the gear's over-centre position due to the minimal adjustment of the threaded stud, led to the gear collapse.