Following an uneventful familiarisation flight the pilot reported that the aircraft was configured for landing with cockpit indications showing the landing gear was extended. Two eyewitnesses observed that the landing gear had extended and looked normal.
Following a normal touchdown the right main landing gear collapsed, quickly followed by the left and then the nose landing gear. The pilot submitted a photograph taken during the landing roll showing the aircraft with both main landing gears retracted but the nose landing gear still extended. The pilot and passenger were uninjured and exited the aircraft without difficulty.
The pilot reported that he checked the position of the landing gear selectors in both cockpits following the incident and confirmed the front selector was down and the rear selector was locked in the neutral position. When the aircraft was lifted using a crane, both main landing gears extended without assistance but the nose landing gear could only be extended when the uplock was released using a screwdriver.
The CJ-6 landing gear is pneumatically operated and the pilot considers that it is possible that the landing gear retracted because of an air leak or anomaly with the landing gear selector(s). At the time of reporting, the aircraft is awaiting repair and the definitive cause is unknown.