What happened
On 30 May 2009, a Piper PA-30 Twin Comanche, registration G-ATEW, was conducting a private flight from Newcastle Airport to Sturgate Airfield in Lincolnshire. During the final approach, the pilot performed a flaps-up landing. While the landing was noted as harder than usual, the aircraft initially rolled normally along the paved runway.
After approximately 300 feet of ground roll, the pilot attempted to switch off the fuel pumps. During this period, the aircraft suddenly began sliding on its belly. The pilot and passenger both reported seeing the green gear-down lights illuminated during the approach, and the gear appeared to be locked upon touchdown. The aircraft slid for approximately 820 metres before coming to a stop. There were no injuries to the two occupants, but the aircraft sustained significant damage to the fuselage, wing underside, and both propellers, rendering it beyond economic repair.
The investigation
Investigators examined the aircraft's landing gear system, which utilizes an electric motor and a complex assembly of torque tubes and push-pull cables. Upon inspecting the aircraft with a crane and jacks, it was discovered that while the nose gear and right main gear could be returned to the locked position, the left main gear remained stuck at a 45-degree angle. This was caused by a bent push-pull cable.
Further examination of the cockpit revealed that the gear selector was in the down position. The pilot suggested that the gear switch might have been accidentally moved while reaching for the fuel pump switches, though the physical movement required to retract the gear is different from the movement used to turn off the pumps. The investigation also noted that the motor's drive had sheared, likely due to the mechanical strain of the motor attempting to retract the gear while the aircraft's weight was forcing it down.
Findings
- The landing gear retraction during the ground roll was the primary cause of the accident.
- There was insufficient evidence to confirm exactly why the gear retracted, though a fault with the anti-retraction safety switch or its rigging could not be ruled out.
- The shearing of the motor drive was a consequence of the motor attempting to operate against the weight of the aircraft on the gear leg.
- The pilot did not perform a visual check of the gear position using the engine cowling mirror during the approach.