History of the Flight
On 26 July 2012 at 15:22 UTC, a Cessna P210N (U.S. registered) was conducting a cross-country flight under visual meteorological conditions (VMC) with two persons on board: the pilot and a student pilot. The aircraft had returned from a previous leg to EBZH. For the landing at Antwerp Airport (EBAW), the pilot performed an ILS approach to Runway 29 as a demonstration. Approximately 0.5 nautical miles from the runway threshold, the pilot selected the landing gear down. The approach was normal with full flaps. The pilot did not recall hearing the gear warning or noting the green indicator light, and confirmed he did not visually check the main landing gear extension. Upon touchdown, the landing was initially smooth, but the aircraft began to swing and settled onto its belly. The pilot contacted ATC, and the aircraft skidded to a stop on its right wing tip about 300 meters past the PAPI. The two occupants exited uninjured before emergency services arrived. The pilot noticed the nose landing gear was fully extended, but the main landing gear had collapsed.
Aircraft and Systems
The Cessna P210N is equipped with hydraulically actuated landing gear. Each leg is raised and lowered by hydraulic actuators, with pressure supplied by an electrically-driven power pack. The system includes a green light indicating all gear locked down, an amber light for gear up, and a throttle-actuated warning system. An emergency hand pump is available for backup extension. The aircraft's flight manual includes procedures for landing gear malfunction, requiring checking the master switch, circuit breakers, and using the emergency pump.
Investigation Findings
Examination revealed the gear pump circuit breaker was found disengaged. The hydraulic oil level in the power pack was low, with oil only visible on the underside of the dipstick. A screen filter was found lost in the airframe near the power pack. Tests with the circuit breaker reset showed the system operated normally for five cycles. However, when the circuit breaker was popped out, selecting gear down allowed the nose gear to lock, but the main gear remained unlocked and hanging. Use of the emergency hand pump successfully extended and locked the main gear. The indication lights and emergency pump were functional. The pilot had recently cleaned the aircraft and replenished hydraulic oil.
Conclusion
The cause of the accident was an undetected malfunction of the landing gear extension which prevented the pilot to take appropriate actions. This led to an abnormal runway contact. The investigation classified the event as a system/component failure non-powerplant (SCF-NP). No safety recommendations were issued.