As the helicopter approached the landing site it “shuddered” and the pilot felt a vibration through the cyclic control and airframe. He was able to control the helicopter’s attitude and elected to land in an adjacent field to avoid endangering persons on the ground.
After shutdown it was apparent that the tip cap of one of the main rotor blades was missing. The cap was not recovered.
Investigation by the manufacturer established that the tip cap had detached because of a surface preparation error that had reduced the strength of the bonded joint.
The manufacturer identified the main rotor blades that were potentially affected and issued Service Bulletin 109SP-116 to introduce a periodic inspection.
The EASA issued Emergency Airworthiness Directive 2017-0176-E to mandate the requirements of the Service Bulletin.
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Published 9 November 2017