Tail Rotor Drive Shaft Failure During External Load Operation in El Hierro

Casualties unknown • El Hierro (Santa Cruz de Tenerife), ES

A Bell 412 helicopter experienced a sudden tail rotor loss of thrust after a polypropylene bag became entangled in the tail rotor, leading to a controlled autorotative landing.

What happened

On March 12, 2010, a Bell 412 helicopter, registration EC-GSK, operated by Inaer Helicópteros, S.A., was performing external load construction work near Valverde, El Hierro. The aircraft departed from El Hierro airport to transport construction materials using a sling load.

During the approach phase to the pickup zone, approximately five miles southwest of the airport, a crew member noticed a white object moving in the air near the aircraft. As the helicopter was at an altitude of approximately 3 meters (15 ft) and flying at a speed below 30 kt, a loud noise was heard on board. Immediately following this, the helicopter experienced a sudden nose yaw to the right, reaching an angle of approximately 60 degrees.

Recognizing the loss of tail rotor thrust, the pilot promptly closed the fuel levers for both engines and initiated an autorotation. This maneuver successfully concluded with a short ground roll. Upon inspection, the crew found a torn polypropylene raffia bag entangled in the tail rotor assembly. There were no fatalities or injuries among the crew or ground personnel, though the aircraft sustained significant damage to the landing gear and the tail rotor drive shaft.

Probable cause

The tail rotor drive shaft failed due to torsional overstress caused by a polypropylene bag becoming entangled in the tail rotor assembly during low-altitude approach.

Frequently asked questions

What happened in the 2010-03-12 Bell 412 accident near El Hierro (Santa Cruz de Tenerife), ES?

A Bell 412 helicopter experienced a sudden tail rotor loss of thrust after a polypropylene bag became entangled in the tail rotor, leading to a controlled autorotative landing.

What aircraft was involved and where did it happen?

The accident on 2010-03-12 involved a Bell 412, registration EC-GSK, at El Hierro (Santa Cruz de Tenerife), ES.

What was the probable cause of the accident?

The tail rotor drive shaft failed due to torsional overstress caused by a polypropylene bag becoming entangled in the tail rotor assembly during low-altitude approach.

Investigation report by the Spanish Civil Aviation Accident and Incident Investigation Commission (CIAIAC). Original record: https://www.transportes.gob.es/recursos_mfom/2010_005_in_0.pdf. This page is a structured re-presentation; facts and quotes are in the Comision de Investigacion de Accidentes e Incidentes de Aviacion Civil (CIAIAC), Spain - Ministerio de Transportes y Movilidad Sostenible.

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