What happened
On 21 July 2008, a Brandli Cherry BX-2, registration G-BXUX, was performing a short local flight from Clipgate Farm Airstrip in Kent. The flight, consisting of a pilot and one passenger, proceeded normally during the takeoff roll. However, at the point of rotation, a loud bang was heard. While the aircraft continued to climb and the crew remained airborne, the pilot observed that the landing gear could not be retracted.
After performing several low passes to assess the situation, the pilot noted that the right main gear appeared to be trailing rearwards. Following consultation with an observer on the ground and another pilot in the vicinity, the crew prepared for a potential emergency landing. Upon touchdown, the landing gear collapsed, causing the aircraft to skid on its belly for approximately 40 metres. There were no injuries to the two occupants.
The investigation
The AAIB examined the aircraft and found significant damage to the engine, propeller, and landing gear mechanism. Specifically, the right wheel had detached from its leg due to a failed weld in a steel fitting.
Further inspection of the airframe revealed that the rear pivot bearing of the right landing gear had moved rearwards, causing the failure of a fuselage crossbeam. The investigation focused on whether this structural failure occurred during the takeoff roll or upon landing. Evidence suggested that the rear pivot bearing was no longer properly located, which subsequently led to the crossbeam failure.
Findings
- The right main landing gear leg was observed to be trailing rearwards while the aircraft was still in flight, indicating the structural failure occurred during the takeoff phase.
- The failure was linked to the rear pivot of the right landing gear leg.
- The investigation identified that the aircraft was operating at a relatively high weight on an uneven grass runway.
- The failure of the crossbeam was likely precipitated by the combined stresses of the aircraft's weight and the loads generated by the undulating surface of the grass runway.
- A contributing factor was a poor adhesive bond on the end grain of the wooden crossbeam, which failed to provide sufficient stability for the bearing locating hole.