2Degrees chief executive Eric Hertz called Air Traffic Control reporting problems with his plane's engines moments before it ditched into the coast off Raglan, killing him and his wife Kathy, an interim Civil Aviation Authority report says.
The couple had been travelling to Timaru to see their daughter Ari when their twin engine Beechcraft Baron plunged into the sea off the Waikato coast on March 30.
In its report released today the CAA said 30 minutes into the flight, after reaching its cruise altitude of 18,000 feet, the aircraft's groundspeed "decreased sharply''.
The aircraft began a "high rate of descent'', and after about one and a half minutes, disappeared from radar, the report said.
In transmissions to Air Traffic Control Mr Hertz indicated he had an emergency and was experiencing problems with both engines.
Acting director of Civil Aviation, Chris Ford said the aircraft was found on the seabed, 59 metres below the surface, inverted but largely intact.
"Examination of the aircraft's propellers indicated that they were under little or no power at the time the aircraft impacted the water,'' Mr Ford said.
"The propeller angles were in a position usually associated with a cruise setting.''
He said the operation to find and recover the wreckage from the seabed was "challenging''.
The CAA inquiry into the accident was continuing, and investigators remained open-minded as to the cause or causes, Mr Ford said.
"There is still a lot of work to be done.''
The focus for the safety investigation was to identify lessons that could be learned and applied in order to prevent future accidents, Mr Ford said.
The investigation had not identified any immediate safety related issues or lessons.
The CAA expected its final report into the crash to be released sometime this year.
The investigation will continue to analyse:
- technical and maintenance history associated with the aircraft;
- Mr Hertz's flying background and experience;
- analysis of Air Traffic Controller voice recording;
- weight and balance calculations;
- flight aerodynamics; and
- regulations relating to foreign aircraft permanently operating in New Zealand.