What happened
On 3 September 1998, a Pierre Robin HR100/285, registration G-BLHN, was conducting a private positioning flight from Ross-on-Wye to Gloucestershire Airport. The flight proceeded normally following departure, during which the pilot retracted the landing gear and received indications that the gear was up. During the transit, the landing gear circuit breaker tripped. After resetting the breaker, the pilot selected the landing gear to the down position to verify functionality. Because the landing gear position indicators showed three green lights, the pilot elected to continue the flight with the gear in the down position.
Upon arrival at Gloucestershire Airport, the aircraft made a light touchdown on Runway 09. Immediately following the touchdown, the right main landing gear and the nose landing gear began to retract slowly. This unexpected movement caused the aircraft to veer right, striking a runway edge light before decelerating on the grass. The pilot issued a 'Mayday' call, shut down the engines, and exited the aircraft before emergency services arrived. The incident resulted in no injuries, though the aircraft sustained damage to the propeller, the right main landing gear door, and the right wing tip and leading edge.
The investigation
Investigators examined the aircraft's landing gear system and performed various tests to understand why the gear retracted without a manual up selection. This included applying loads to the gear to simulate operational stresses and attempting to induce movement. The investigation also included a detailed examination of the mechanical and electrical components of the landing gear system.
Findings
- The investigation could not find any mechanical or electrical defects within the landing gear system.
- Testing failed to replicate the conditions that would allow the gear to retract while the indicators showed the gear was down, without the pilot selecting the up position.
- The cause of the gear retraction remains unidentified.