What happened
On November 16, 2005, at approximately 13:25 local time, a PIPER PA-28R-201T, registration EC-GDF, was conducting a dual-instruction flight for an ATPL course at Son Bonet Aerodrome in Palma de an Mallorca. The flight, operated by Panamedia, S. L., included an instructor and two students. After completing several maneuvers and a series of take-offs and landings, the crew was cleared to land on runway 24.
Upon landing, the aircraft taxied toward the final runway exit. As the crew initiated a right-hand turn to exit the runway, the left main landing gear leg began to retract gradually. The instructor took control of the aircraft and steered it off the paved surface to avoid remaining on the taxiway. During the subsequent recovery maneuver, the wingtips struck the ground repeatedly as the left main gear leg collapsed multiple times. All three occupants (one instructor and two students) were able to evacuate the aircraft safely after cutting the fuel and master switches. The aircraft sustained minor damage to the wingtips, the pitot tube, and both sides of the horizontal stabilizer.
The investigation
The investigation focused on the mechanical integrity of the landing gear system. While the aircraft and engine were up to date with maintenance schedules, a thorough inspection of the landing gear and its related systems was conducted in a hangar. The investigation confirmed that there were no hydraulic failures and that the operating pressures for both extension and retraction were correct.
However, inspectors discovered that a bracket within the squat switch assembly—the component responsible for preventing gear retraction while the aircraft is on the ground—was installed incorrectly. The investigation compared the actual assembly to the manufacturer's service manual, noting that the bracket had been modified and improperly secured.
Findings
- The primary cause of the incident was the improper installation of the squat switch bracket.
- The bracket, which functions as a plunger to activate the switch, had been shortened and was held in place only by the head of the connecting bolt.
- This specific configuration allowed the bracket to rotate around the bolt, effectively neutralizing the squat switch's ability to prevent gear retraction.
- The investigation concluded that the landing gear retraction was likely triggered by an inadvertent movement of the landing gear lever, as the safety mechanism intended to prevent such an action while on the ground was non-functional.