Executive summary
On Friday 23 April 2004, Helicopter Services UH-1B helicopter ZK-HSF was on a ferry flight to Gore to facilitate maintenance work. En-route near Mokoreta a main rotor blade separated, the helicopter broke up and fell to the ground. The pilot, the sole occupant, was killed and the helicopter was destroyed.
The accident resulted from fatigue failure of a tension-torsion (TT) strap, a critical rotor hub component. The fatigue cracking had probably been initiated by an unreported rotor overspeed event.
Safety issues identified included:
· The need for pilots to understand the importance of reporting a rotor overspeed event
· The need for FAA and CAA airworthiness personnel and licensed maintenance engineers to recognise and respond to documented improper identification of critical finite-life components such as the TT straps
Safety recommendations to address these issues were made to the Director of Civil Aviation, and to the Administrator of the United States Federal Aviation Administration.
Related Recommendations
ensure that other company pilots properly record flight times in aircraft documents and their pilot logbooks.
develop educational material to ensure that helicopter pilots understand the significance of a rotor overspeed event, and what action should be taken.
develop educational material for FAA airworthiness personnel to raise awareness of the need for them to recognise and respond to documented inadequate identification of critical lifed components when checking aircraft maintenance documents.
ensure that company pilots do not attempt tasks of aircraft maintenance that are beyond the scope of approved pilot maintenance.
develop educational material for CAA airworthiness personnel and licensed maintenance engineers to raise awareness of the need for them to recognise and respond to documented inadequate identification of critical lifed components when checking aircraft maintenance documents.