History of the Flight
The pilot, the sole occupant of the Mooney M20J (N12ZX), departed Oxford (Kidlington) Airport on an IFR flight plan to Szczecin, Poland. Within one minute after takeoff, the pilot observed that the landing gear had not retracted. The cockpit indications showed a 'Gear Unsafe' warning light and a mechanical indicator stuck between the gear up and locked down positions, indicating the gear was partially extended but unlocked. The pilot notified the tower and flew for approximately one hour outside the ILS sector and in the VFR pattern, attempting to lock the gear up or down. A manual gear extension system exists for electrical problems, but the pilot tried numerous times without success. The pilot had previously tested the system successfully during the last 100-hour maintenance while the aircraft was on jacks. The pilot flew past the tower, and ATC confirmed the wheels were out but at a strange angle. The pilot decided to land on the paved runway (Runway 19) rather than grass to minimize the risk of flipping. After touchdown, the gear collapsed as anticipated, and the aircraft came to a stop upright. The pilot exited through the door with no injuries. The aircraft sustained minor damage to the propeller, engine, lower skin, and collapsed landing gear; the runway had minimal damage.
Aircraft Damage
Inspection in the hangar revealed scrape marks on the outside of the nose gear doors, the aircraft belly skin, and other areas, consistent with damage likely sustained during the landing. The steel lugs on the nose gear had sheared from their 'A-frame' weld attachments, indicating the gear collapsed on landing and folded back into the gear bay. Additional damage was noted in the landing gear retraction system: the right-hand connecting rod was bowed, the left-hand connecting rod was eroded, and a pin on the right-hand side was missing. It is likely that the bowed and eroded rods were caused during the landing. It was not possible to ascertain whether the missing pin would have caused the gear to jam.
Assessment of the Cause
The pilot considers that the cause of the gear retraction failure was either an actuator failure or a structural failure within the mechanical linkage. The actuator was to be tested, but the results were not available at the time of publication.