After takeoff the pilot selected the gear up but only the left main gear locked up while the right main gear unlocked and then remained in a semi-retracted state. The pilot left the circuit and made numerous attempts at trying to extend both main gear using both the normal and emergency pneumatic systems. He also tried various aircraft manoeuvres including yawing, pitching and pulling G but the gear indication system always showed that one landing gear was unlocked. After conducting a couple of low fly-bys at the airfield to confirm the state of the landing gear he decided to land on the grass surface alongside the paved runway. During landing both main gear collapsed, the oil cooler on the belly was torn off, and the propeller suffered damage. The pilot vacated the aircraft unassisted. An examination of the gear system revealed that the O-ring seals on the right main gear actuator piston were rolled. The rolled seals caused a leak that prevented the air pressure from fully extending both main landing gear.
Published 10 December 2014