Eurocopter AS 350 B3 Ecureuil accident in Forada del Toscar (EC-JRJ)

Incident Overview and Location On Thursday, October 10, 2007, at 10:30 local time, a Eurocopter AS 350 B3 Ecureuil helicopter with registration EC-JRJ crashed in the Forada del Toscar area of Huesca, Spain. The aircraft was operated by Sky Helicópteros and was engaged in commercial aerial work, specifically the transport of logs. The crash occurred in the Las Abichachas area, near the Lanau estate, adjacent to a paved road connecting the towns of Senz and Viu. ## Aircraft and Operational Details The helicopter, serial number 4077, was manufactured in 2006 and had accumulated 473 flight hours at the time of the accident. It was powered by a single Turbomeca Arriel 2B-1 engine. The aircraft was equipped with an external load system consisting of an external load hook and a remote load hook suspended from it. The remote hook's electrical opening system had been modified by cutting the original cable and installing a conventional plug system, a modification that was not documented in the aircraft's records and did not use standardized aeronautical material. ## Sequence of Events The pilot was transporting a log approximately 15 meters long and weighing 630 kg. The log was suspended by a 7-meter sling extended by a 3-meter shock-absorbing rope. During the operation, the lower end of the log became stuck in the ground and was further trapped by another log on the terrain. The log bent forward and broke approximately 1 meter from its lower end. This caused the helicopter to perform an uncontrolled counterclockwise rotation around its vertical axis. The pilot attempted to counteract the rotation using the right pedal but was unable to do so. The helicopter completed slightly more than one full rotation, moved laterally to the left, and impacted the terrain. The aircraft did not overturn but came to rest slightly on its right side. The log remained attached to the helicopter throughout the incident. ## Casualties and Damage The 49-year-old pilot, who held a commercial helicopter pilot license and had 6,882 total flight hours (3,021 in type), was killed in the accident. There were no passengers on board. The helicopter sustained significant damage, including a fractured tail cone, severe damage to the main rotor head and blades, and damage to the tail rotor blades. The landing skis on the right side were destroyed. Additionally, one of the main rotor blades cut a guardrail on the access road to Senz. ## Investigation Findings Post-accident inspections revealed that the fuel feed lever was in the cut-off position and the main switch was disconnected. The collective control was fully up, and the engine throttle was in the idle position. The load hook opening switch was found in the ON position. Engine parameter displays recorded a torque exceedance of 137% for two seconds during the flight. Functional tests of the remote hook system showed very low reliability, with recurrent failures. The failure rate was lower when the female connector of the adapted plug was manipulated simultaneously with the switch. Disassembly of the plug revealed a poor electrical connection in one of the conductors, with evidence of oxidation on a union screw indicating excessive overheating.