What happened
On 2 June 2001, a De Havilland DH11ly Venom FB1, registration G-GONE, was participating in a three-aircraft formation flight approaching Biggin Hill Airport in Kent. The aircraft was flying from Bournemouth, Dorset, as the third element in a formation preparing for an annual air display.
During the downwind leg of the approach to Runway 21, the pilot performed standard pre-landing checks. During this process, the pilot noticed the flap position indicator showed a setting greater than the required one-third. The pilot corrected the flap position but continued the approach. As the aircraft entered the turn to final, the pilot focused on maintaining even spacing within the formation and avoiding the wake turbulence from the two leading aircraft.
While performing the turn, the pilot checked the undercarriage indicators. Due to difficult lighting conditions, the pilot was unable to clearly see the lights but concluded that the gear was down, subsequently announcing 'FINALS THREE GREENS' to the tower. The aircraft subsequently touched down on its belly. The pilot only became aware that the wheels were not extended after being notified by Air Traffic Control. The aircraft sustained damage to its underside, but the pilot exited the aircraft uninjured.
The investigation
The investigation examined the cockpit configuration and the pilot's actions during the landing sequence. It was noted that the pilot had recently returned to the type, having flown the aircraft only once in the preceding eight years. The investigation looked into the visibility of the undercarriage position lights, which the pilot had previously noted were dim and difficult to read due to their position on the lower left of the instrument panel.
Findings
- The pilot's focus on maintaining formation spacing and avoiding the slipstream of the preceding aircraft acted as a distraction.
- The undercarriage and flap levers are positioned closely together and feature similar designs, which led to the pilot mistakenly operating the flap lever instead of the undercarriage lever.
- The pilot failed to realize that the incorrect flap setting observed during the downwind leg was a consequence of the misapplied lever.
- The undercarriage position indicator lights were difficult to discern due to their location and low intensity in the prevailing light conditions.