What happened
On April 12, 2001, a PIPER PA-34-220T, registration EC-EYV, was operating a general aviation pleasure flight from Sabadell to Palma de Mallorca. The aircraft landed smoothly on runway 06L at Son San Joan Airport. During the braking phase while attempting to turn onto taxiway N-5 near gate D, the nose gear collapsed. The aircraft slid approximately 10 meters along the runway before coming to a stop. Both the pilot and the passenger were uninjured.
The investigation
The investigation examined the aircraft's maintenance history and the mechanical state of the landing gear. While investigators identified that a mandatory Airworthiness Directive (AD 93-24-14)—which requires the replacement of the AN7-35 bolt connecting the nose gear trunnion to the upper drag link every 500 hours—had not been properly implemented during the most recent 1,000-hour inspection, post-accident inspections revealed that this specific bolt had not fractured.
Furthermore, the investigation looked into the hydraulic landing gear system, which uses an electric pump to actuate the gear. The pilot reported that the cockpit indicators showed the gear as extended and locked during the landing. The investigation focused on whether the nose gear was physically unsecured or if the cockpit instrumentation was providing misleading information.
Findings
- The aircraft's nose gear collapsed during taxiing following a normal landing.
- The cockpit instrumentation provided a false indication that the landing gear was fully extended and locked.
- The nose gear sensor was improperly adjusted, which caused it to signal the electric pump to stop before the gear had fully deployed.
- Although the required replacement of the AN7-35 bolt had been overlooked in previous maintenance intervals, the bolt itself was not broken at the time of the accident.
- The collapse resulted in significant damage to the nose gear, the lower forward fuselage, and the propeller blades.