Incident Summary
On 11 May 1999, at 1654 UTC, a Piper PA-34-200T, registration G-BPON, was on a positioning flight from Bournemouth to Gloucestershire Airport. The pilot, accompanied by two passengers who were also qualified pilots, conducted a landing on Runway 22, which has a hard surface. The wind was reported as 220° at 12 knots, and the aircraft was configured with 25° of flap. The pilot observed three green indicator lights confirming the landing gear was extended and locked prior to touchdown. The landing was described as normal; however, after a short ground roll, the nose landing gear collapsed. The aircraft came to a stop with minimal damage, and the occupants evacuated without difficulty.
Aircraft Information
The aircraft involved was a Piper PA-34-200T, manufactured in 1975, powered by two Continental TSIO-360-E piston engines. The pilot held a Commercial Pilot Licence with 728 hours total flying experience, including 58 hours on type. The flight was conducted under private category.
Investigation Details
Post-incident examination of the nose landing gear extension system revealed no faults. No hydraulic leaks were found, and the landing gear locked down properly during repeated ground tests. The rigging of the downlock mechanism was assessed to be correct. The nose gear is locked in the extended position by a drag link that assumes an over-centre position when correctly rigged. A spring strut acting at one end normally holds the drag strut in the over-centre position. The maintenance manual contains full rigging details, but partial disassembly is required to verify the correct amount of over-centre. It has been known for this type of nose gear to become unlocked if misrigged or if vertical loads are induced by rough ground conditions.
Status of Investigation
The aircraft is currently awaiting repairs. The nose landing gear and its retraction/extension system will be inspected and overhauled during maintenance. Any significant findings from this process are to be published in an AAIB Bulletin Addendum. The probable cause of the collapse has not been determined from the available evidence.