What happened
On February 23, 2006, a Piper PA-24-180, registration CS-ALT, departed Faro Airport for a visual flight rules (VFR) trip to Cascais with a pilot and three passengers. Shortly after takeoff, the pilot attempted to retract the landing gear. Although the gear moved, the cockpit indicator lights showed that the gear had not locked in the "UP" position. Shortly thereafter, the occupants noticed a burning smell in the cockpit.
At a distance of 13 nautical miles from the Faro VOR, the pilot notified Air Traffic Control (ATC) of the intention to return to the departure airport. Upon attempting to extend the gear for landing, the pilot found that the gear had not locked in the "DOWN" position. A manual extension attempt was also unsuccessful. The pilot requested a low pass in front of the Control Tower to verify the gear's position; the controller confirmed the landing gear legs were stuck at a 45-degree angle.
The pilot declared an emergency and executed an approach to runway 10. To minimize the impact, the pilot maintained a low approach speed with full aileron deflection to maximize lift. Upon touchdown, the gear collapsed completely, causing the aircraft's fuselage to strike the asphalt. The aircraft slid 128 meters along the runway, eventually coming to a halt 90 degrees to the runway centerline. The four occupants were able to exit the aircraft uninjured.
The investigation
The GPIAAF examined the aircraft's landing gear retraction system, including both the mechanical and electrical actuators. The investigation found that the mechanical emergency actuator showed no anomalies. However, inspectors identified evidence of overheating in the electrical actuator motor.
Analysis of the flight path and impact marks indicated that the gear had likely retracted but failed to lock, causing the electric motor to work under excessive load, which produced the burning smell. The investigation also noted damage to the aircraft's lower fuselage, propeller deformation, and destroyed communication antennas located under the belly. The propeller strike also caused damage to the runway surface.