Twelve seconds after a routine radio transmission, the commander of a Eurocopter AS332 L2 Super Puma was back at the microphone, declaring an emergency as his helicopter fell 2,000 ft from cruise flight to the surface of the North Sea. The two pilots and all 14 passengers were killed, and the helicopter, which lost its main rotor during the plunge to the sea, was destroyed in the April 1, 2009, crash.
The U.K. Air Accidents Investigation Branch (AAIB), in its final report, said the crash followed the catastrophic failure of the main rotor gearbox, which resulted from a fatigue fracture of “a second stage planet gear in the epicyclic module.”
The report added that the only indication of a pre-existing problem was the discovery during maintenance on March 25, 2009 — 36 flight hours before the accident — of a metallic particle on the epicyclic chip detector and that “the possibility of a material defect in the planet gear or damage due to the presence of foreign object debris …
