What happened
On March 9, 2015, at approximately 14:00 hours, a Socata TB-10 Tobago, registration EC-DQB, was performing a private local flight from La Juliana aerodrome in Seville, Spain. After completing a successful engine test and takeoff from runway 09, the aircraft began its initial climb.
While passing over the threshold of runway 27 and preparing for a right-hand turn, the pilot observed smoke emerging from the engine cowling and noted a loss of engine power. In an attempt to avoid a parachute landing zone located to the north of the runway, the pilot entered a right-hand turn. During this maneuver, the aircraft descended into a medium-voltage electrical line. The cable became entangled in the right main landing gear, causing the aircraft to strike the ground in an olive grove. The aircraft slid for approximately 80 meters before coming to a halt. The pilot was uninjured, though the aircraft sustained significant damage to the landing gear, propeller, engine, and both wings.
The investigation
The CIAIAC investigation focused on the mechanical condition of the engine and the maintenance history of the aircraft. Investigators discovered that pieces of adhesive tape, used previously to repair the engine baffle, had detached and come into contact with hot surfaces on the exhaust muffler, which generated the observed smoke.
Regarding the aircraft's airworthiness, the investigation revealed several critical discrepancies. The aircraft's Certificate of Airworthiness had expired three months prior to the accident. Furthermore, the investigation found evidence of poor maintenance practices, including the presence of a mouse nest within the engine cowling and unrecorded modifications to the engine accessories. While the magnetos were found to be in poor condition with improper clearances, functional tests performed during the investigation showed they were still capable of operating the engine.
Findings
- The primary cause of the accident was pilot error in the reaction to the appearance of smoke, which led to an uncontrolled descent into the power lines.
- A significant contributing factor was the pilot's lack of recent flying experience and the absence of a flight refresher course after a period of inactivity.
- The aircraft was in a precarious state of maintenance, with expired airworthiness documentation and neglected scheduled inspections.
- The presence of debris from improper repairs (adhesive tape) acted as the trigger for the smoke event.
- The aircraft had been subject to infrequent use, contributing to its overall neglected condition.