What happened
On 1 April 2009, at approximately 12:55 UTC, a Eurocopter AS332L2 Super Puma, registration G-REDL, was performing a commercial passenger flight when it crashed approximately 11 miles north-east of Peterhead, Scotland. The accident resulted in 16 fatalities, comprising the two crew members and 14 passengers. The helicopter was destroyed upon impact.
The investigation
AAIB investigators have been examining the wreckage of the epicyclic gearbox, the main rotor gearbox, and related aircraft components. The investigation aims to determine the precise sequence of events and the initial trigger for the mechanical failure.
Investigators discovered that a small metallic chip had been found in the epicyclic gearbox module chip detector roughly 34 flying hours prior to the accident. However, no further indications of an impending gearbox failure were identified during the period between that discovery and the crash.
Findings
Preliminary findings indicate that a failure occurred within the epicyclic reduction gear module of the rotor gearbox. This failure caused the gearbox case to rupture, which subsequently led to the separation of the main rotor head from the helicopter. The investigation is ongoing to identify the specific cause of this internal component failure.
Safety action
Following the accident, the AAIB issued Safety Recommendation 2009-051. It recommends that Eurocopter, in coordination with the European Aviation Safety Agency (EASA), implement a mandatory inspection of the internal components of the main rotor gearbox epicyclic module for all AS332L2 and EC225LP helicopters, effective immediately.