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.