A well-known ''idiosyncrasy'' in the fuel system of the Piper Cherokee aircraft is being considered as a possible cause of the fatal Glenorchy Air crash near Alexandra earlier this month.
The Transport Accident Investigation Commission's (TAIC) investigation into the August 5 crash is temporarily on hold while staff focus on Saturday's fatal Helicopter Line crash on Mt Alta, near Wanaka.
However, chief investigator Tim Burfoot says it is ''well aware'' of a quirk of the aircraft's design in which pilot error can lead to fuel not being delivered to the engine.
Queenstown pilot Ray Crow was killed and two passengers injured when the Piper Cherokee 6 crashed just north of the Poolburn Reservoir on August 5.
Texan passengers Sarah (31) and Erik (35) Hoffmann told the Otago Daily Times last week they had no recollection of the crash.
Mrs Hoffmann remains in Dunedin Hospital, where she is ''progressing well'', while Mr Hoffmann has been discharged.
Veteran Dunedin pilot John Penno has flown about 2000 hours in Piper Cherokees during his 45-year flying career.
He said they were a ''good, solid machine'' well-suited to mountain flying, but were notable for requiring the pilot to manually switch between their four fuel tanks.
''On the odd occasion there have been accidents when people haven't managed their fuel systems properly, and run out of fuel in one tank while coming in to land and that sort of thing,'' Mr Penno said.
Mr Burfoot said that ''little idiosyncrasy'' in the aircraft's fuel system was ''definitely a factor that needs to be considered''.
''We're well aware of that, but whether it was a factor in this case, is difficult to say ... we don't have a pilot to talk to.
''It's something I'm hoping we can get out of the wreckage - of whether there was actually fuel being delivered to the engine.''
The initial analysis of the engine by an independent assessor in Feilding had been completed but he had yet to receive the results.
The Otago Daily Times contacted the aircraft's manufacturer, Florida-based Piper Aircraft, for comment on this aspect of its fuel system.
The company's director of marketing and communications, Jacqueline Carlon, said in an emailed response the company was co-operating with the New Zealand authorities, and ''as such, we are unable to provide any comments related to the accident''.
