The report says the plane had left Taupo Airport on January 7, 2015, on its fourth flight of the day, with six tandem masters, six riders and a pilot aboard. When it had climbed to about 2100ft (640m) above Lake Taupo a loud bang came from the engine and sparks from the exhaust. The propeller stopped. The pilot shut down the engine, put the plane into a glide and broadcast a mayday call.
The tandem master nearest the pilot quickly assessed that bailing out would be safer than a forced landing and shouted "get out". Each tandem master then checked they were attached correctly to their rider before they shuffled to the cabin rear door and jumped.
The last pair aboard saw the pilot hit the top of the wing, forward of the cabin door, then fall away. They then left the aeroplane. In all, the bail-out is estimated to have taken up to 20 seconds.
Everybody landed on dry land by the lake shore. Two people suffered minor injuries. The plane struck the water at high speed about 150m offshore and was destroyed.
The report says the cause of the accident was engine failure because of a fatigue crack in a compressor turbine blade. The failed blade was one of a set of overhauled blades that was well within its inspection interval. Although it had been inspected only 87 flight hours previously, it was likely only one side had been inspected.
The failed blade and two others were undersize in some dimensions compared with new blades, which might have contributed to fatigue failure. However, the aircraft engine had been maintained in accordance with an approved programme.
The report also found that although the pilot was competent, it was likely that his emergency procedures training was inadequate, which contributed to him making "a hasty exit from the aeroplane that jeopardised others".
After the crash, Skydive Taupo painted the rear bulkheads of its planes white, which allowed pilots to see people more easily in the rear-view mirror, added a voluntary tandem jump to the parachute pilot training as well as group training with tandem masters, and provided lifejackets to tandem masters.
Engine manufacturer Pratt & Whitney Canada revised its repair requirement document for compressor turbine blades and advised it would revise its manual to require enhanced inspections of all single-engine aircraft used for skydiving.
Skydive Taupo owner and chief executive Roy Clements said it was important to remember the pilot had been placed in a very stressful situation and had made the best decisions he could at the time.
"He genuinely believed that when he left the plane, that everybody else had already exited," Clements said.
"To this day I'm still really proud of the way the guys dealt with the situation and I think it's a credit to them that their skill has prevented us dealing with a coronial inquest."
He said the pilot was still flying, but had moved away from Taupo.
