NTSB Reacts To 2004 Eurocopter Crash, Recommends SB Compliance

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The National Transportation Safety Board this week formally recommended that the FAA require operators to comply with an existing service bulletin affecting Eurocopter model AS-350-BA helicopters in the wake of a 2004 accident that injured three. The accident, which involved a television news operation on May 4, destroyed the helicopter and resulted from a loss of hydraulic system power while hovering. The NTSB's investigation determined that the hydraulic pump drive belt failed in flight, approximately 160 flight hours short of its 600-hour life limit. Post-accident examination of the hydraulic pump drive belt at the NTSB's Materials Laboratory found the belt had been installed inside out. According to the NTSB, the belt's failure and subsequent lack of power to the ship's hydraulic pump meant a rapid loss of hydraulic system pressure.

In addition to having been installed inside out, the belt's exterior surface, as installed, displayed numerous lateral cracks. In addition to the facts of this accident, the NTSB found some 43 failures and/or replacements of the drive belts since February 1995. Some 460 AS-350 helicopters of various models are currently in operation in the U.S. Eurocopter issued a service bulletin on May 27, 2002, which offered an improved drive belt with a significantly longer service life of 1,500 hours. The service bulletin recommended replacement of the old-style belt with the new one along with hydraulic pump drive pulleys and pulley bearings. A Jan. 21, 2003, fatal accident in Mekatina, Ontario, also involving a Eurocopter AS-350 helicopter, resulted from failure of an old-style belt, according to the Transportation Safety Board of Canada.