What happened
On June 14, 2002, at approximately 13:15 local time, an Agusta Bell AB 205 helicopter, registration EC-GJL, was performing aerial thermography inspections of power lines near Toraiola, Lleida. The aircraft had departed from Sabadell Airport earlier that morning, picking up passengers in Lleida before proceeding toward the Baqueira Beret helipad.
While maintaining level flight, the helicopter's tail cone separated from the fuselage. Following the separation, the fuselage began to spin and descended into the terrain. The impact caused the wreckage to catch fire, and all eight occupants (four crew members and four passengers) perished in the accident.
The investigation
The CIAIAC investigation focused on the structural integrity of the tail assembly and the maintenance practices of the operator, Helieuropa Services. Investigators examined the wreckage, including the engine, rotor components, and the transmission system, finding no evidence of prior malfunction in those specific components. However, analysis of the tail cone fragments indicated a static failure associated with an overload.
The investigation also scrutinized the regulatory oversight provided by the DGAC. It was discovered that the aircraft's airworthiness certificate did not accurately reflect its actual design configuration. Furthermore, the investigation found significant deficiencies in the operator's maintenance management, noting that daily and line inspections were not properly controlled and that the operator lacked updated airworthiness instructions from the manufacturer.
Findings
- The primary cause of the accident was the separation of the tail cone from the fuselage due to an overload on the tail assembly.
- This overload likely originated from previously undetected, significant static damage on the right side of the tail cone, which caused a redistribution of stresses that exceeded the structural strength of the left-side fuselage longerons.
- The accident was likely exacerbated by the aircraft operating at load conditions near its limits, which may have catastrophically developed the existing structural damage.
- There was a probable failure to perform required daily and pre-flight inspections of the tail cone skin as mandated by the manufacturer's instructions.
- Maintenance practices were non-compliant with manufacturer specifications, and the operator lacked adequate procedures for flight inspections and operational control.