What happened
On 11 May 1999, a Piper PA-34-200T, registration G-BPON, was performing a private positioning flight from Bournemouth to Gloucestershire Airport. The flight was operated by a commercial pilot accompanied by two passengers, both of whom were qualified pilots.
During the approach to Runway 22, the crew confirmed that the landing gear indicators showed '3 greens', signifying the gear was down and locked. The landing was conducted using 25 degrees of flap with a wind of 220 degrees at 12 knots. While the initial touchdown on the hard surface was normal, the nose landing gear collapsed after a very brief ground roll. The aircraft stopped with minimal damage, and all three occupants evacuated the aircraft safely without injury. The incident resulted in damage to the aircraft nose and propellers, and the engines sustained shock loading.
The investigation
Investigators examined the aircraft's nose landing gear extension system following the incident. The inspection revealed no hydraulic leaks and confirmed that the gear locked into the down position correctly during repeated testing. Furthermore, the rigging of the downlock mechanism was found to be within correct parameters.
Technical analysis focused on the drag link mechanism, which is designed to hold the nose gear in an over-centre position when properly rigged. It was noted that this specific type of nose gear is susceptible to unlocking if the system is misrigged or if vertical loads from rough ground surfaces induce movement in the system.