What happened
On May 12, 2018, a Mooney M20K, registration D-ETFT, was conducting a private flight from Cascais, Portugal, to Reus, Spain. The flight, which had begun earlier that morning, proceeded uneventfully until approximately 13:24 UTC, when the pilot was notified that the destination airport, Reus, was closed to VFR traffic due to deteriorating weather conditions.
While attempting to divert to an alternate airport in Sabadell, the pilot reported engine difficulties. At 13:34 UTC, the aircraft experienced a complete loss of engine power. Following the failure, the pilot managed the descent for approximately five minutes, eventually attempting an emergency landing on a section of road T2237 in the municipality of Flix. The aircraft's wingspan exceeded the width of the mountain road, leading to a series of impacts. The left wing struck trees, causing the aircraft to destabilize, followed by the right wingtip striking a guard rail and the fuselage impacting the ground. The crash resulted in 3 fatalities.
The investigation
The CIAIAC investigation focused on the sequence of events leading to the engine failure and the circumstances of the emergency landing. Investigators examined the aircraft's engine components, specifically the fuel manifold valve, and analyzed the flight planning and meteorological conditions. The investigation also reviewed the maintenance history of the fuel system and the physical wreckage to determine the cause of the impact sequence.
Findings
- The primary cause of the accident was the destabilization and loss of control during the attempt to land on a road narrower than the aircraft's wingspan.
- The engine failure was caused by the complete fracture of the nozzle distribution line to the #3 cylinder on the fuel manifold valve due to fatigue.
- Manufacturing defects in the weld between the tube and the head of the distribution line, including lack of filler and misalignment, facilitated the fatigue fracture.
- Deficient flight planning regarding weather and area analysis caused the flight to be prolonged, placing the aircraft in a mountainous region where an engine failure left no viable aerodrome options.
- The pilot effectively managed the descent and correctly evaluated available options, but the terrain constraints made a safe landing impossible.
Safety action
- A safety recommendation was issued to Continental Motors to review the manufacturing and welding procedures for the nozzle distribution lines in the fuel manifold valve to correct identified defects such as wall thickness discrepancies and microfolds.