David Baldwin, a commercial pilot and aviation examiner, described seeing the aircraft in a "near vertical climb" at about 25m to 30m followed by a stall turn to the left and a brief vertical descent. It briefly managed to pull its wings level before crashing.
Helicopter pilot Andrew Gutsell said the aircraft gained altitude with the nose lifting in a "text book stall" at about 60m when it plummeted, without sufficient airspeed, and crashed, left wing first.
None of the passengers were restrained, which probably resulted in "load-shift" as passengers slid to the rear of the aircraft during the ascent, throwing it off its centre of gravity. Eight of the bodies were found in the tail section.
Mr McElrea recommended passenger restraints for tandem parachuting operations be urgently considered across the industry. He also recommended similar aircraft used for parachute operations be restricted to six people and the pilot.
Mr McElrea said it was likely the aircraft was above its allowable weight limit by some 67kg.
The operator had been unaware that, after its conversion from an agricultural plane, the centre of gravity had moved backwards by 5cm.
"It is clear on the evidence that load-shift forces that occurred when the aircraft was in operation were an essential element in the crash," Mr McElrea said. "The more aft [behind] the centre of gravity, the less the stability of the aircraft."
It was possible the pilot's control column had been broken, or else a loose object in the cockpit had jammed the pitch control mechanism, although these would be rare events.
Mr McElrea said Chaminda Senadhira had a good reputation as a pilot, however, a pilot-related factor could not be ruled out.
Transport Minister Gerry Brownlee said he would have a "very good look" at the coroner's recommendations and saw no reason why it should not be made mandatory for passengers on skydiving trips to wear restraints.
The Transport Accident Investigation Commission also investigated the crash and found two of the commercial skydivers on board had cannabis in their systems. Mr McElrea said this would not have contributed to the outcome.
PM backs improvements
Prime Minister John Key is committed to improving safety in the adventure tourism industry and his Government will consider recommendations made by the coroner investigating the Fox Glacier tragedy.
A spokeswoman for Mr Key yesterday said the Prime Minister continued his "personal commitment" to ensure tourists to New Zealand did not face unnecessary risks.
The industry's reputation has taken a battering in recent years, with questions over the quality of safety standards and cannabis links to people involved in both the Fox Glacier and Carterton balloon tragedies, which together claimed 20 lives. The revelations that the pilot of the Carterton hot air balloon had cannabis in his system and so too did two skydive masters in the Fox Glacier crash has prompted the Government to consider mandatory drug testing in the tourism industry.
Mr Key last year announced new regulations requiring tourism providers to have stronger processes for dealing with drug and alcohol use.
His spokeswoman yesterday signalled the Prime Minister intended to continue putting pressure on the sector.
Skydive Fox Glacier director Mark Horning said he hoped the reputation of the adventure tourism industry would be partially repaired by the release of the coroner's finding.
The ruling that the cause of the 2010 tragedy was unlikely to ever be fully understood showed the crash was an accident.
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