Speculation about a fatal plane crash continues, Jenna Lynch reports. --------------------
A Waikato aviation expert believes more than just engine failure was responsible for the "complex" plane crash that killed 2degrees boss Eric Hertz and his wife, Kathy.
Yesterday, a Civil Aviation Authority (CAA) report outlined how the cause of the crash was still undetermined, but Hamilton-based airline aviation expert Ewan Wilson said after reading the report, the rapid rate of decline pointed to an engine stall.
"My gut feeling is the aircraft has stalled and he's been unable to rescue the aircraft from that stall.
"What triggered the stall, I'm unsure."
Eric Bennett Hertz, 58, and Katherine Picone Hertz, 64, were in their twin-engine Beechcraft Baron when it plunged into the sea off Kawhia Harbour on March 30 this year. The plane was on its way from Ardmore to Timaru when it crashed at 12.20pm.
The wreckage was found by navy divers at a depth of 56 metres, then hauled from the seabed and transported to the CAA workshop in Wellington to be dismantled and examined "piece by piece".
The CAA's interim factual report into the Easter Weekend accident outlined that 30 minutes into the flight, after reaching its cruise altitude of 18,000 feet, the aircraft rapidly lost speed, and disappeared from radar a minute and a half later.
Mr Wilson said it was likely either the plane had a twin-engine failure, or the temperature and weather conditions coupled with an engine failure might have been the cause of the stall. He said, under normal circumstances, a pilot who encountered an engine failure at an altitude of 18,000ft should be able to get the plane back under control - meaning the cause of the crash was likely "complex".
"I'm astonished that from the onset of the stall to the impact was only 90 seconds," he said.
"I think it's more than just an engine failure."
In transmissions to air traffic control, the pilot indicated he had an emergency and was experiencing problems with both engines, the report said.
Acting director of Civil Aviation Chris Ford said early examinations showed the plane's propellers were "under little or no power at the time the aircraft impacted the water".
"The propeller angles were in a position usually associated with a cruise setting," he said.
The report also details that neither propeller was feathered - which means the propellers blades are rotated so that the leading and trailing edges are nearly parallel with the aircraft flight path, making it easier for pilots to fight drag from a failed engine.
Investigations into the accident were ongoing and the CAA would examine the technical and maintenance history of the aircraft and an analysis of air traffic controller voice recording to determine the cause of the crash, Mr Ford said.
"We remain open-minded as to the cause or causes.
"There is still a lot of work to be done," Mr Ford said.
The CAA is expected to release its final report into the accident later this year.
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