Incident Overview
On Wednesday, 3 November 2010, at 12:00 local time, a Piper PA-34 Seneca III, registration EC-KTT, was conducting a verification flight for the renewal of multi-engine and instrument ratings at Madrid-Cuatro Vientos airport. The flight was planned with a departure and return to the same airport, with an intermediate stop at Ciudad Real airport. On board were an examiner authorized by AESA and two pilots being checked, both holding commercial pilot licenses (CPL(A)).
Sequence of Events
During the takeoff roll on runway 28, after covering approximately one-third of the runway length, the nose gear collapsed. The pilot under check was at the controls in the left seat. The examiner, seated in the right seat, immediately took control. The aircraft deviated from the centerline, following a curved path of about 180 meters toward the left runway edge, dragging the nose gear doors and leaving a mark on the asphalt. It came to a stop near the left edge at the intersection with taxiway E2, with its longitudinal axis oriented at 265° magnetic.
According to the crew, the aircraft initially rested on the main landing gear, but shortly thereafter the left main gear retracted, causing the left wing tip to contact the ground. Both propellers struck the ground, and all three blades were bent rearward. The left main gear was found retracted, while the right main gear was extended but not locked. The three occupants were uninjured and evacuated the aircraft unaided.
Damage
The aircraft sustained minor damage to the nose gear doors, forward fuselage fairing, left wing tip, and both propellers.
Investigation Findings
During the investigation, the crew stated that they had not moved the landing gear lever to initiate retraction. A post-incident inspection conducted 30 minutes later found the mixture controls cut off, propeller levers forward (fine pitch), throttle levers at idle, fuel selector on, and the landing gear lever in the down position.
The aircraft was lifted with a crane, and the main gear wheels were manually blocked. Before lowering, the nose gear was manually extended and locked. Subsequent functional tests with the aircraft on jacks involved five complete gear cycles; the system operated correctly, with the gear locking down and cockpit indications functioning normally.
The down lock link assembly of the nose gear was disassembled for examination. None of the attachment bolts showed deformation. The spring that assists in unlocking the overcenter mechanism was found to be in normal working condition. The down lock link's central pin had normal play, and its hole was not ovalized, remaining within the maintenance manual tolerances. Additionally, during the test cycle, hydraulic fluid leaked from a damaged pipe, preventing a check of the fluid level. After replacing the pipe, the gear system performed normally.
Probable Cause
The investigation did not identify a specific cause for the nose gear collapse. No probable cause was stated in the report.