AAIB investigation to Sud Aviation SA342J Gazelle, YU-HET
During a maintenance check the helicopter inadvertently became airborne and landed heavily, Stapleford Aerodrome, 6 July 2015.
The helicopter inadvertently became airborne during a hydraulic system check with the engine running. It was not possible to determine why the helicopter became airborne. During the investigation it was found that the pressure switch was not fitted to the hydraulic pack and hence the low hydraulic pressure warning would not activate. A safety concern relating to the overhaul of the engine was also identified.
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Published: 10 November 2016
Date of occurrence: 6 July 2015