What happened
On 20 May 2016, a Piper PA-28RT-201T Turbo Cherokee Arrow IV, registration G-LZZY, was performing a private flight when the pilot encountered issues with the landing gear during the approach to Shoreham Airport. While the nose and left main landing gear indicators showed green, the indicator for the right main landing gear failed to illuminate.
Following a request for a ground visual inspection, the pilot was informed that the gear appeared to be in a satisfactory position. However, due to the uncertainty, air traffic control declared a full emergency. While awaiting the deployment of the airport's Rescue and Fire Fighting Service (RFFS), the pilot attempted to rectify the issue by recycling the landing gear and performing the emergency extension checklist, which involved using the backup gear extender. The pilot also replaced the bulb in the right main gear indicator with a functional one, but the light remained unlit.
Upon landing on Runway 2le, the engine was shut down after the aircraft came to a stop. However, as the aircraft settled on the runway, the right main landing gear collapsed, resulting in a cracked right main landing gear door and damage to the right flap.
The investigation
An investigation by the AAIB examined the sequence of events and the mechanical state of the aircraft. The pilot, an experienced commander with over 16,000 flying hours, reported that the primary cause of the incident was the failure of the right main landing gear downlock to engage.