What happened
On 20 September 2002, a Piper PA-34-200T Seneca II, registration G-BEHU, was performing a private flight from Staple Hay to Prestwick Airport. The aircraft was carrying the pilot and four passengers. During the approach to Runway 13, the pilot confirmed the landing gear was down and locked, even using a mirror to visually verify the nose gear extension.
The landing itself was described as very smooth. However, immediately after touchdown, as the pilot applied the brakes and retracted the flaps, the aircraft began to vibrate heavily. The left propeller struck the runway, followed shortly by the right propeller. The aircraft then slid along the runway on its underside, eventually rotating 90 degrees before coming to a halt. There were no injuries to the pilot or the four passengers, though the aircraft sustained significant damage to the propellers, wings, and fuselage.
The investigation
Investigators examined the aircraft's landing gear system, which is hydraulically operated and electrically controlled. Upon inspection, it was noted that while the gear selector was in the DOWN position, the nose gear was fully retracted with its doors closed, and the main landing gears were sagging. The underside of the aircraft showed extensive scraping, particularly on the left side, consistent with the aircraft being low on its left wing.
Extensive system tests were performed while the aircraft was supported on jacks. These tests included checking the hydraulic pressure, the operation of the warning lights and horn, and the functionality of the manual emergency extension. The investigation also looked into the state of the circuit breakers, as some related to the landing gear pump and control had tripped.
Findings
- The landing gear system, including all warning lights, horns, and hydraulic functions, was found to be operating correctly according to the manufacturer's manual.
- No mechanical faults or dormant failures were discovered in the wiring, hydraulic, or electrical systems during the inspection.
- The landing gear retracted unexpectedly during the landing roll, causing the aircraft to strike the runway with its propellers and slide on its belly.