History of the Flight
On 7 September 2020, the pilot of G-AYSY, a Cessna F177RG, returned to Leicester Airport after a flight to Newquay via Cardiff. Earlier that day, the pilot had completed three circuits without issue. The landing gear was lowered before landing, and both the green indicator light and an external mirror confirmed it appeared down and locked. After a normal touchdown, the aircraft slowed as expected. The pilot retracted the flaps, and as the speed passed about 40 mph, a metallic sound was heard, and the nose gear collapsed. The aircraft traveled approximately 70 metres on its main wheels before stopping with the nose on the runway. Both occupants vacated the aircraft with minor injuries.
Aircraft Information
G-AYSY is a 1971 single-engine retractable tricycle gear aircraft equipped with an electrically driven hydraulic power pack. The nose gear uses an over-centre mechanical lock and has proximity microswitches for sequencing. A green indicator light illuminates only when all gear legs are down and locked and the hydraulic pump stops. A mirror in the cockpit allows visual inspection. The aircraft had a previous landing gear issue in 2019 due to a hydraulic pipe failure, which was repaired.
Aircraft Examination
After the incident, a centre torque link bolt was found on the runway, missing its nut. The bolt and the torque link showed damage from runway contact. No other nose gear components were damaged. The retraction/extension system was tested and functioned normally. The maintenance organisation considered the bolt damage as a result of runway contact rather than a cause of the collapse.
Analysis
Two possible scenarios were considered: (1) The nose gear was not fully extended and locked, despite the indicator showing down and locked, possibly due to a misaligned microswitch. (2) The pilot inadvertently retracted the gear when reaching for the flaps, and the squat switch may not have prevented retraction if weight was not on the nose wheel. The pilot stated he did not accidentally move the gear handle. No conclusive evidence was found.
Conclusion
After landing, the nose gear collapsed. The damage to the torque link bolt and link was attributed to runway contact and was unlikely causal. No other faults were found. It was not possible to determine whether a technical fault or inadvertent retraction caused the collapse.