On approach to Shoreham Airport the pilot selected the landing gear DOWN and, although green lights illuminated to indicate the nose and left main landing gear were locked down, the green light for the right main landing gear did not illuminate.
The pilot requested a visual inspection from the ground and, once this was completed, he was informed that the landing gear “appeared ok”. However, in preparation for the aircraft’s arrival, air traffic control initiated a full emergency and the pilot, now holding to the west of the airport, waited for the airport’s RFFS to deploy. During this time, the pilot recycled the landing gear and completed the ‘Emergency Landing Gear Extension’ checklist which included a step to lower the landing gear using the backup gear extender. In addition, he swapped the bulb in the right main landing gear indicator with one that was known to be working, but the indicator remained unlit. Once the RFFS were in place, the pilot made an approach to Runway 25, stopping the engine after touchdown but, as the aircraft settled, the right main landing gear collapsed. The uninjured pilot turned the fuel and electrics off and vacated the aircraft. He attributed the cause of the accident to the right main landing gear downlock failing to engage.