What happened
On June 14, 2020, a Piper PA-28R-201T, registration EC-FFP, departed from the Casarrublarubios del Monte aerodrome in Toledo, Spain, for a series of local takeoff and landing maneuvers. The pilot, the sole occupant, performed the flight under VFR conditions.
During the flight, the pilot retracted the landing gear while climbing through the upwind leg. While transitioning to the downwind leg, the pilot extended the gear and reported seeing three green indicator lights, suggesting the gear was down and locked. During the landing roll, the nose gear collapsed, causing the front of the aircraft to strike the runway. The impact caused the propeller blades to strike the pavement, resulting in the engine stopping immediately. The pilot was uninjured and able to exit the aircraft on his own.
The investigation
The CIAIAC investigation focused on why the nose gear failed to lock despite the cockpit indications. Investigators examined the landing gear mechanism and found no structural damage or deformation to the nose gear strut or the extension/retraction mechanism.
Crucially, the investigation identified that a heating system air duct had become detached from its intake. This loose pipe was found trapped between the steering bearings and the bell crank of the nose gear assembly. The investigation determined that the clamp holding the pipe had been insufficiently tightened, allowing the pipe to gradually slip out of place. Once loose, the pipe was moved by airflow and became lodged in the nose gear mechanism, likely preventing the gear from completing its full extension and locking.
Regarding the cockpit indications, the investigation found that the landing gear warning lights were functioning correctly. However, the pilot's perception was likely compromised by two factors: the low angle of the sun during the downwind leg, which could have created glare on the indicator lights, and confirmation bias, where the pilot expected to see the green lights because he had heard the gear mechanism operating normally.
Findings
- The primary cause was the pilot's erroneous perception of the landing gear indicator lights, which led to landing without realizing the nose gear was not locked.
- A contributing factor was the interference from a detached cabin heating air duct, which prevented the nose gear from fully extending and locking into place.
- The pilot's perception of the gear status was likely influenced by sun glare and confirmation bias.