What happened
On 16 April 2009, a Beech 76 Duchess, registration G-BODX, was conducting an instrument rating training flight at Bournemouth Airport. The flight crew consisted of an instructor and a student pilot, with an additional student observer in the rear seat. Following several instrument approaches and go-arounds, the student pilot performed an asymmetric approach and a go-around, followed by a visual circuit to complete the landing.
During the visual circuit, the landing gear was not selected into the down position, and the flaps were not extended beyond 15 degrees. As the aircraft flared, it experienced a prolonged float, likely due to the lack of drag from the retracted landing gear. The aircraft subsequently touched down on its underside approximately 800 metres beyond the runway threshold. The aircraft slid to a stop, and while there was no fire, the impact caused significant damage to the underside and both propellers, which were bent, and the engines were shock-loaded. The aircraft was declared beyond economic repair. There were no injuries to the three occupants.
The investigation
The investigation examined the configuration of the aircraft and the cockpit procedures during the final stages of the flight. It was noted that the landing gear warning horn did not alert the crew to the configuration error. The investigation established that in this specific aircraft model, the warning horn sounds intermittently only if the throttle is retarded below a specific setting sufficient to maintain height with the gear up. Furthermore, the horn is not triggered by the gear position alone, regardless of throttle position. The investigation also looked into the flap settings, noting that if flaps had been extended beyond 16 degrees, the warning horn likely would have sounded.
Findings
- The landing gear was not deployed during the visual circuit.
- The flaps were not extended beyond 15 degrees, which prevented the landing gear warning horn from activating.
- The failure to deploy the landing gear was a primary factor in the prolonged float and subsequent underslung landing.
- The instructor noted that the student's focus may have been diverted by previous approaches and the fact that this was the final landing of the day.
- The operator had not yet implemented formal Standard Operating Procedures (SOPs), though students were instructed to use full flaps once below the asymmetric committal height.