What happened
During a specialized training exercise, a helicopter was performing a takeoff from a confined area while simulating a one-engine-inoperative condition. During the maneuver, the aircraft's rate of descent increased excessively, leading to a hard landing. While the impact resulted in structural damage to the helicopter, there were no injuries reported among the occupants.
The investigation
The Swedish Accident Investigation Authority examined the circumstances surrounding the training profile and the operational oversight of the exercise. The investigation focused on why the aircraft deviated from the intended flight path and the lack of-risk assessment prior to the maneuver. The inquiry also looked into the oversight capabilities of the relevant aviation safety organization responsible for monitoring such activities.
Findings
Investigators determined that the primary cause of the accident was that the training exercise was conducted significantly outside of the established exercise profile, and the inherent risks of such a deviation were not identified.
A contributing factor was the absence of clear, predefined criteria regarding the specific conditions under which the exercise should have been aborted.
At a systemic level, the investigation identified an underlying cause involving the ancillary aviation safety organization. Due to staff turnover and a lack of personnel, including nominated persons, the organization lacked sufficient insight into the specific elements of the practice and had failed to perform necessary risk assessments for the exercise.