Helikopterfelle #2

NTSB Cites Methane Gas as Culprit in Oil Rig Accident
The National Transportation Safety Board (NTSB) believes methane gas expelled from an offshore oil rig in the Gulf of Mexico caused the partial power failure on a Bell 206-L3 helicopter departing the MP61A platform on March 24, 2011. The pilot experienced the power failure at about 4:55 p.m., shortly after liftoff. The NTSB attributed the power loss to an engine compressor stall after it ingested methane gas during takeoff. The Board issued five safety recommendations on August 26, one of which was addressed to the American Petroleum Institute about platform gas. The helicopter pilot told investigators he believed he had cleared the boom safely, but heard a loud bang as he passed abeam the structure and immediately noticed an increase in torque and turbine outlet temperature before the power loss. Although he initiated an autorotation and extended the float system, the helicopter rolled inverted after contacting the water. The pilot and two passengers received only minor injuries but the helicopter was destroyed. The NTSB said that while the platform has a windsock to determine prevailing wind, it does not have a system to alert pilots when the flare boom is venting methane gas. The investigation discovered that the volume of gas vented through the platform’s boom was 20 times higher on the day of the accident than on the second highest day recorded that same month.