Trousers caused crash
The helicopter crash that killed two Twizel-based Department of Conservation (DOC) workers was caused by a pair of over-trousers flying from the machine’s cabin and becoming tangled in the tail rotor, investigators say.
DOC biodiversity ranger Scott Theobald, 59, and senior ranger Paul ‘Hondy’ Hondelink, 63, both based in Twizel, along with Wanaka-based pilot Nick Wallis, 38, died in the crash near Wanaka Airport on October 18 on their way to carry out tahr control in the Haast area.
The Transport Accident Investigation Commission (TAIC) has published an interim report into the crash.
It found paint marks on the over-trousers matched the colour and profile of the tail rotor blades, and marks on a tail rotor blade matched a zip and dome connector on the overtrousers.
TAIC chief commissioner Jane Meares also said there were three incidents in the month prior, in which doors on the same Hughes 500 helicopter opened in flight.
Jonathan Wallis, the older brother of Nick Wallis and managing director of the family company The Alpine Group, said the unexplained door separation was concerning.
‘‘Since that accident in October we have been made aware of numerous incidents of doors opening in-flight on the same aircraft make and model.’’
In the crash, the helicopter plummeted about 300 metres to the ground shortly after take off from Wanaka Airport.
The helicopter had been leased from aviation company Airwork by the Wallis family’s company and had been heading to the first day of the Department of Conservation’s controversial tahr cull.
The report said that less than a minute after leaving the airport several witnesses saw the helicopter descending near vertically, with items trailing behind it, and the helicopter rotating at various angles.
Two experienced instructors flying a Robinson helicopter nearby saw items coming out of the helicopter towards the tail rotor.
One of the witnesses saw what appeared to be a chilly bin falling.
‘‘They saw the helicopter rotating in an upright attitude until it struck the ground.’’
It caught fire after impact, which consumed most of the wreckage.
However, aircraft parts and items that had been in the cabin were scattered over a distance of about 500m from the main wreckage, including the pair of black, padded, bib over-trousers and the pair of red, padded overalls that had been inside of the cabin.
They were found close to the separated tail section, along with two pieces of the tail rotor blades and the tip of one of the main rotor blades.
Meares said the October crash report highlighted the risk posed by loose items in the cabins of helicopters.
The Civil Aviation Authority (CAA) had taken action to remind aviation participants of the risk of loose items in the cabins of helicopters.
With regards to the previous occasions where the helicopter door had opened, the commission recommended urgent action by the CAA director to remind aviation participants of the importance of reporting incidents in accordance with Civil Aviation rules.
‘‘Effective safety management depends on such incidents being reported and investigated, but none of these occurrences was recorded in the operator’s incident reporting system,’’ Meares said.
The reports issued yesterday are interim reports, so include no formal findings.
Jonathan Wallis said The Alpine Group unreservedly supported the safety message pertaining to the stowage of loose items, as well as the recommendation to aviation participants to be reminded of occurrence notification.
As TAIC and the CAA were still investigating, the company would not make further comment.
‘‘Since that accident in October we have been made aware of numerous incidents of doors opening inflight on the same aircraft make and model.’’ Jonathan Wallis