The manufacturer of the type of aircraft that crashed at Fox Glacier said an accident report released today supported its belief that the tragedy could have been avoided if its concerns over modifications to the aircraft had been acted on.
An investigation into the plane crash that killed nine people at Fox Glacier 20 months ago has found modifications to the aircraft were poorly managed.
The crash claimed the lives of Mapua man Christopher McDonald, 62, Skydive New Zealand director Rod Miller, 55, of Greymouth, pilot Chaminda Senadhira, 33, of Queenstown, dive masters Adam Bennett, 47, from Australia who was living in Motueka, and Michael Suter, 32, from New Plymouth.
The four tourists, who had been touring the West Coast on a Kiwi Experience bus trip, were Patrick Byrne, 26, of Ireland, Glenn Bourke, 18, of Australia, Annita Kirsten, 23, of Germany, and Brad Coker, 24, of England.
A Transport Accident Investigations Commission (TAIC) report released today found the aircraft had been modified from an agriculture plane into a parachute-drop plane three months before the accident.
Its owner had not completed any weight and balance calculations before it entered service in its new role.
As a result, it was being flown outside its loading limits every time it carried a full load of eight parachutists.
No two aircraft of the same model are exactly the same, even if they look that way, so pilots must do weight and balance calculations for every individual aircraft, the report said.
TAIC said the Civil Aviation Authority (CAA), which approved the aircraft's change of category, failed to detect discrepancies in documentation.
In February last year the manufacturer of the aircraft went public with fears that the widespread practice of putting more powerful engines in the planes could have been a factor in that and other fatal crashes.
Hamilton-based Pacific Aerospace Limited (PAL) suggested that the September 2010 crash, New Zealand's worst aviation disaster in 17 years, could have been avoided if its concerns had been acted on by aviation authorities.
PAL spoke publicly after an approach by the Nelson Mail, but the claims were disputed in aviation circles.
The CAA said last year it had extensively assessed the Fletcher FU-24 aircraft and believed it had responded appropriately to the concerns.
PAL chief executive Damian Camp said today the findings of the report backed the company's concerns. Fragmentation of responsibility for modifications to the aircraft had in the end left no-one responsible, Mr Camp said.
He said PAL was still the type certificate holder for the unmodified aircraft.
"What we have here is an aircraft made 30 years ago for a role in agriculture and 18 years later it's significantly modified and re-powered without our involvement.
"Then it's significantly modified again in 2010 to a skydive plane. Our concern is that without the involvement of the original type certificate holder there are divisions in responsibility," Mr Camp said.
The company had been particularly concerned at the practice of operators putting more powerful engines in the planes.
He said CAA still had oversight, but when multiple parties were introduced gaps opened up in the chain of responsibility, which Mr Camp believed was what had happened with the Fox Glacier accident.
"Without one person being responsible, no-one was responsible. That's what's happened here," Mr Camp said.
CAA director of Civil Aviation Graeme Harris said the report provided lessons for all pilots, and for the CAA.
The commission has found that the pilot had wrongly used weight and balance calculations for another Fletcher aircraft, he said.
The Skydive New Zealand plane crashed soon after takeoff from Fox Glacier airstrip. TAIC said the Fletcher FU24 aircraft was off balance, becoming airborne at too low a speed to be controllable.
The cause of the accident was blamed on the plane being out of balance, with the centre of gravity 12cm rear of the maximum permissible limit, making the nose "pitch up".
The pilot got the plane airborne too early and at too low an airspeed.
Key recommendations focused on weight and balance (the plane had been too heavy and out of balance), plane modification (the plane had been modified for skydiving), introduction into service, regulator oversight and alcohol and drug testing.
The pilot was unable to regain control and the plane continued to pitch up, then rolled left before striking the ground nearly vertically.
TAIC made six recommendations to the CAA director – three relating to the operation of parachute-drop aircraft, two relating to the process for converting aircraft for another purpose and one relating to seat restraints.
Witnesses said the plane became airborne in a normal way but began "pitching" upwards before plummeting down.
The report found the pilot had not been drinking but the need for a deterrence and testing regime was highlighted, and safety restraints were needed to prevent parachutists from going too far to the plane's rear.
Modifying aircraft was a safety-critical process that must be done in strict accordance with rules and guidelines and with appropriate regulatory oversight, the report said.
Two of the dive masters had THC – an active ingredient in cannabis – in their blood, the report said. THC has mild to moderate analgesic effects.
The CAA now has much better tools with which to regulate the commercial skydiving sector.
A new adventure aviation rule was introduced in November 2011, which sets higher standards and allows the CAA to maintain significantly closer oversight of these activities.
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