The RAN Board of Inquiry into the incident concluded that the accident was caused by human error -- the duty engineer failed to shut down both engines -- .
Members of Onslow 's complement disagree with this , claiming the problem to be mechanical in origin .
The RAN Board of Inquiry into the incident concluded that the accident was caused by human error -- the duty engineer failed to shut down both engines -- but members of Onslow 's complement disagree with this , claiming the problem to be mechanical in origin .