Accident
On 12 April 2003, at approximately 17:20 UTC, an Eurocopter EC-120B helicopter registered as F-GKHH, operated by Pyrénées Transport Hélico, was conducting a local sightseeing flight from Tarbes Laloubère aerodrome. After about 45 minutes over the Pyrenees, the pilot returned and joined the circuit for runway 26. During the flare, the helicopter entered an uncontrolled left yaw rotation. The pilot could not stop the rotation. After two to three full turns, the tail boom neared the ground, then the helicopter climbed with significant pitch variations, banked left, and struck the ground. The front left passenger was killed; the helicopter was destroyed. No other injuries or damage occurred.
Aircraft
The helicopter was an EC-120B Colibri, serial number 1122, first placed in service on 26 January 2001, owned by Lifrapos SARL and leased by Pyrénées Transport Hélico. It had 215 flight hours. The VEMD recorded no pre-impact malfunctions. The pilot, aged 41, held a professional helicopter license with 207 total hours, including 8 hours 15 minutes on type. Weather was wind 040°/4 kt, visibility over 10 km, temperature 13 °C, QNH 1015 hPa.
Investigation
The BEA investigation found that the yaw control cable had been severed by a main rotor blade striking the tail boom. The central blade of the yaw control cable was broken at both crimps due to tensile forces from the impact. The rear transmission shaft showed static fractures consistent with power transmission. The left front seat dual controls were present, with the left pedal in a high position and the right pedals low. The investigation concluded that the dual controls in the left front seat had been inadvertently unlocked, interfering with yaw control.
Probable Cause
The BEA determined that the probable cause of the accident was loss of yaw control during the flare due to the inadvertent unlocking of the dual controls in the left front seat.