Flying low over a remote airstrip in a plane to clear livestock before landing is a risky tactic, an aviation industry CEO said yesterday.
The Transport Accident Investigation Commission yesterday released a report into a Piper Cherokee crash near the Poolburn Reservoir in Central Otago on August 5, 2014, which killed the pilot and injured two tourists.
Queenstown pilot Ray Crow, 56, died, American tourists Sarah, 31, and Erik, 35, Hoffmann were seriously injured when the plane crashed during a Glenorchy Air Lord of the Rings sightseeing flight.
The report concludes the Piper stalled during a low-flying manoeuvre as Crow tried to to clear cattle off an airstrip before landing.
Its main recommendation was for Civil Aviation director Graeme Harris to provide a clear statement to relevant sectors of the aviation industry on whether stock-clearing was a permitted activity, as there was a "lack of clarity" in Civil Aviation Rules.
The Civil Aviation Authority (CAA) said in the report there was no rule specifically referring to stock-clearing.
"The director will agree to pursue a means to enable air transport operators to overfly a remote airstrip below 500ft for the purposes of ensuring the landing area is visibly free from hazards."
When asked yesterday if this meant rules would be changed to allow the manoeuvre, and that clear guidelines be created for its conduct, CAA communications adviser Jess Jennings said the authority stood by comments made in the report.
Chief executive of industry body Aviation New Zealand, John Nicholson, said he "welcomed the clear direction" of the report.
"From our viewpoint, using aircraft to clear stock from airstrips is a risky activity. It is much safer for farmers to do this on the ground. Ultimately though, pilots must make sure remote strips are free from hazards before landing."
The report would provide "momentum for the future" to improve safety in the industry by creating a more informed relationship between the CAA, the aviation industry and its customers, he said.
Glenorchy Air co-owner Robert Rutherford said the report was "speculation".
"We're a bit disappointed.
"We don't think it tells us really what happened. It's all a bit of a mystery."
The company did not train its pilots to execute such manoeuvres, he said.
"It becomes uncontrolled and our business is about having everything under control. If he had been trying to move stock, that's not how he'd go about it.
"There are a whole lot of things that can't be ruled out."
Commission investigator Peter Williams said Rutherford was given the chance to respond to the draft report.
"His response was taken into consideration when the final report was being prepared for publication."
The report said the aircraft stalled while Crow was turning at a low level to perform a second pass over the airstrip to scare away the livestock before landing. It occurred at a height too low to enable recovery before the aircraft hit the ground, it said.
Both passengers were interviewed for the report and Erik Hoffman recalled Crow saying during the flight he would need to dip the plane low to scare cows off a runway near Poolburn.
Pilot incapacitation and mechanical failure were "very unlikely" to have been contributing factors, the report said.
Operators must issue clear guidelines and procedures for their pilots to follow, and ensure they were being complied with, the report said.
"Pilots should be required to regularly demonstrate proficiency in carrying out the types of manoeuvres and operations they perform for the operator."