North Weald: Helicopter's engine failure demo 'led to serious incident'

The helicopter rejected take-off and made a "firm landing" at North Weald Airfield, the report said

A helicopter training exercise to demonstrate engine failure led to a "serious incident", a report said.

The pilot of a MBB-BK 117 helicopter had to make a "firm landing" during an exercise at North Weald airfield in Essex, on 12 March, 2021.

It happened after he reduced throttle in one engine to simulate failure, according to the Air Accidents Investigations Branch (AAIB).

There were no injuries but the landing gear of the helicopter was damaged.

The pilot was taking part in the exercise at the airfield to revalidate his instructor qualification and an examiner was present, the AAIB report said.

Shortly after reducing engine one's throttle, the pilot increased the setting - but it did not respond.

While attempting to resolve the problem, the throttle setting for engine two was "inadvertently reduced", the report added.

It said this "probably resulted from the commander's hand accidentally overlapping its throttle" as he tried to increase engine one.

"The investigation heard that inadvertent manipulation of the throttles during high stress/workload situations was an uncommon, but not unknown occurrence on this type of helicopter," the report said.

Investigators said the incident "reinforces the benefit of using flight simulators wherever possible to de-risk training".

The training exercise was taking place at the airfield in Essex

The pilot rejected take-off while at 19ft (5.8m) above ground level.

A "firm landing" was carried out which left skid marks on the airfield and caused "significant deformation" of the landing gear, the report said.

The AAIB said the operator had tried to organise flight simulator training but no suitable options were found.

Pending the outcome of the AAIB investigation, the operator elected to only conduct similar training with both engines at flight.

It also now provides simulator-based training for scenarios involving one engine.