The apparent lack of significant damage to the rotor blades of the helicopter that crashed on Fox Glacier on Saturday has raised a suggestion the cause of the crash could have been mechanical failure.
An experienced helicopter pilot spoken to by the Otago Daily Times yesterday said it was unusual for the fibreglass blades of an AS350 Squirrel helicopter not to be badly damaged in a crash.
"A helicopter that went into that location under power would have had the blades pretty much ripped off."
A photo of the crash scene shows little obvious damage to two of the three blades.
The pilot, who did not want to be named, said the intact blades suggested to him they were turning under very little momentum when they hit the ice. If the chopper had suffered an engine failure, the blades were still likely to be turning - but a transmission system failure could lead to the blades becoming locked up.
Transmission failures were highly unlikely, but not completely outside the bounds of possibility. There could well be other reasons for the blades not being damaged, he said, but it was very unusual.
A second experienced helicopter pilot consulted did not believe the amount of damage to the blades was an indication of the cause of the crash.
The blades would not necessarily be badly damaged in a helicopter that hit the ground under power, he said.
Alpine Adventures pilot Mitch Gameren, 28, died with six tourists in the crash. The tourists were Andrew Virco, 50, and his partner, Katharine Walker, 51, of Cambridge, England; Nigel Edwin Charlton, 66, and his wife, Cynthia, 70, of Hampshire, England; and Australians Sovannmony Leang, 27, and Josephine Gibson, 29.
Police yesterday revealed they had recovered four of the bodies - not three, as they had previously stated - from the crash site on Sunday. Inspector John Canning said there had been an error in recording.
Police were now working to identify the victims using photos of them and their belongings, DNA samples and dental records if needed. Disaster victim identification staff were also on hand to help.
The remaining three bodies are unlikely to be retrieved until tomorrow at the earliest, when it was thought the weather could clear enough for crews to approach the site.
Mr Canning said the glacier was moving about 1m a day, presenting safety challenges.
Families of the victims were expected to arrive at some point, but travel arrangements were still being finalised.
Transport Accident Investigation Commission spokesman Peter Northcote said investigators had spent yesterday conducting formal interviews with people connected to the tragedy. "These include employees of the operating company and others working in the same area on the morning of the accident.
"Meanwhile, an engineering expert for the helicopter type has been preparing equipment to assist with securing the wreckage while police operations take place nearby, and to prepare it for recovery.
"Planning of a drone aerial survey mission has also continued working off existing photography and an investigator's aerial reconnaissance of the wreckage scene.
"The investigation team's current priority is to secure all available physical evidence and to obtain witness statements," he said. The team could then confirm what extra expert help it might need to examine the wreckage.
- additional reporting: NZME