Relatives of four tourists killed in an aircraft accident in New Zealand have written to the country's prime minister to urge him to bring in stronger safety enforcement.
The letter follows publication of the report of the inquest into the nine deaths at Fox Glacier in one of New Zealand's worst recent air crashes. Skydive New Zealand's Fletcher FU24 aircraft crashed shortly after take-off on September 4, 2010.
Coroner Richard McElrea said the cause may never be fully known, but unrestrained passengers shifting the balance in the overloaded plane probably contributed, news agency NZ Newswire reported.
The country's Transport Accident Investigation Commission ruled earlier that the crash was caused by an unbalanced, overloaded plane. However, its Civil Aviation Authority (CAA) discounted this and said the cause was unknown.
Mr McElrea said the pilot did not have control of the plane at any time. It was about 67kg overloaded, though this was still within the limits of the weight it should be able to carry. Unrestrained passengers had moved backwards during take off, increasing the plane's instability, but it was "likely that some other factor has also occurred", Mr McElrea said.
"It's unlikely that the cause of the crash will ever be fully understood," the coroner said. "Something unusual, such as inadvertent pilot error or engine malfunction/mechanical failure, has occurred at take-off. This, coupled with the aircraft being overweight and loaded rearwards of its centre of gravity, is consistent with the evidence and has been the immediate cause of the tragedy."
Aviation law in New Zealand does not require passengers to be strapped in. Mr McElrea recommended passenger restraints for tandem parachuting operations be "urgently considered for implementation across the industry" to prevent inadvertent load shift during take-off and landing, and that all Fletcher series aircraft or equivalent planes be restricted to carrying six people.
The parents of the four tourists who died - 24-year-old web designer Bradley Coker, of Farnborough, Hampshire, Patrick Byrne, 26, of County Wexford, Ireland, Glen Bourke, 18, of Australia, and Annika Kirsten Schmidt, 23, of Germany - wrote to New Zealand prime minister John Key calling for action.
The others who died were the pilot and four "tandem masters" - crew who assist passengers to undertake a parachute jump while attached to them.
They regard the findings of the accident report and the inquest "disturbing" and call on the prime minister to "take decisive and unequivocal action to reassure the world that New Zealand is a very safe place to visit".