On the day of the crash the helicopter was conducting a gas line inspection flight under contract to Bord Gais. The inspection flight had begun at Gormanstown in Co. Meath with the intention of ending at Foynes on the Shannon estuary. In the vicinity of Lisheen on the Clare side of the River Shannon the helicopter descended and entered a 360 turn in order to allow closer inspection of work on the surface. It was during this manoeuvre that the engine stopped suddenly and without warning. The pilot lowered the collective in attempt to enter autorotation but the helicopter impacted heavily on farm land. The cockpit was effectively destroyed in the impact. The observer was pronounced dead at the scene and the pilot was airlifted to hospital in Galway by the Coast Guard helicopter.
The subsequent investigation determined that the sudden stopping of the engine was caused by the disintegration from fatigue of a 41 tooth bevel gear in the engine accessory gear box. The gear box provides drive to the Fuel Control Unit. Loss of drive caused fuel flow to cease with the engine stopping within seconds. The investigation found that in addition, the altitude of the helicopter at the time of the accident was too low to safely establish an autorotation manoeuvre.
Posts
No comments:
Post a Comment