Piper PA-34-200 Nose Gear Collapse at Sabadell Airport (EC-JHQ)

Incident Overview and Flight Details On July 31, 2005, at 12:02 local time, a Piper PA-34-200 with registration EC-JHQ was involved in an accident at Sabadell Airport in Barcelona. The aircraft was privately operated and was on a local visual pleasure flight. The flight, which lasted 1 hour and 21 minutes, proceeded normally until the landing phase. The pilot, a 57-year-old private pilot with 637:50 total flight hours and 69:25 hours on type, reported that the approach was conducted according to procedure. After a soft touchdown, the pilot noticed the aircraft sinking and pulled back on the controls to keep the nose up. As the aircraft decelerated, the elevator lost effectiveness, causing the nose to drop and drag along the runway. The aircraft deviated slightly to the left and stopped approximately halfway down the runway, with the propellers also striking the pavement. All three occupants, including the pilot and two passengers, were uninjured and evacuated the aircraft under their own power. The aircraft sustained minor damage to the nose gear doors, forward fuselage, and both propellers. ## Technical Investigation and Findings The Piper PA-34-200 is equipped with a tricycle retractable landing gear system powered by a reversible electric pump. The nose gear is secured in the extended position by an over-center mechanism held in place by a down lock link. Following the incident, a detailed inspection of the nose gear locking mechanism revealed that the over-center was not firmly held by the down lock link, allowing the gear to unlock. Upon disassembly, the screw connecting the down lock link to the retraction link was found to be severely bent in the area where the down lock link's clevis is located. ## Maintenance History and Probable Cause The manufacturer, New Piper Aircraft, had issued Service Bulletin No. 1123A on November 30, 2004, due to a high number of incidents related to the nose gear of Piper PA-34 aircraft. This bulletin provided instructions for inspecting and replacing nose gear components, including the down lock link, which was to be inspected at 100, 500, and 1,000-hour intervals. At the time of the accident, no Airworthiness Directive made this bulletin mandatory. The aircraft had recently been purchased by its owner and had undergone a 50-hour inspection, during which the down lock link was not inspected. The last inspection date for the nose gear components could not be determined. The investigation concluded that the nose gear retracted because the over-center was not properly secured by the down lock link. This improper securing was caused by the shortened length of the down lock link, which resulted from the deformation of the connecting screw. The deformation of the screw was likely caused by bending stresses from one or more hard landings.