An Air New Zealand pilot who fell into a deep sleep twice while at the controls of a passenger flight says he was fatigued because he could not rest properly in London hotel rooms that were "too hot or too cold".
The pilot, who was flying a 332-seat Boeing 777-300ER between London and Los Angeles in 2011, said issues at the hotel had been ongoing and contributed to his exhaustion before the mid-flight slumber.
He has the backing of the Air Line Pilots' Association, which last night said the incident showed the importance of air crew being "provided with quality hotel rest".
Transport Minister Gerry Brownlee has called on Air New Zealand to prove its safety standards. "You need to satisfy the public you're making sure your pilots aren't asleep on the job. You've got big reputation issues here; this doesn't look good," Mr Brownlee said on 3 News.
Last night an airline spokeswoman said a second pilot on the flight deck was aware his colleague had fallen asleep and "safety was not compromised at any point".
She said the pilot had "nodded off twice for around a minute and woke spontaneously".
However, the pilot himself said: "I suddenly, and without any warning, fell into a deep sleep on the flight deck."
The pilot reported the November 2011 incident himself and detailed the events to the Civil Aviation Authority, which has released its report.
The pilot told the authority he had three room changes in the first two days during a London stopover because the air conditioning at the hotel made the rooms "too hot or too cold".
The unrest contributed to his exhaustion from having only a one-night stopover at Los Angeles on the way to London.
"Despite the room changes in London, my rest prior to duty was much improved but still not of the highest quality," he said. "I was of the belief I had adequate rest and was fit to continue with the rostered duty."
Heavy fog at Heathrow Airport had resulted in a 50-minute delay in take-off, compounded by "a very long taxi" and an additional delay of about 40 minutes. "This added considerably to our workload before we were airborne," the pilot said.
After falling asleep twice on the flight deck and also having two rests in the plane's bunk, the pilot said, he "felt much better and continued to LAX without further difficulties".
A spokesman for the pilots' association said the flyer "acted appropriately" by reporting this occurrence. "It is extremely important that crew report these type of events to ensure the robustness of mitigation processes already in place," he said.
The Air New Zealand spokeswoman said: "We recognise the risks of crew fatigue and as part of our safety culture we support and encourage staff to self-report incidents of fatigue, which is what occurred."
Air New Zealand's chief executive, Christopher Luxon, told 3 News he wasn't aware of the incident and would investigate what happened.
The airline's chief pilot, Captain David Morgan said: "The reason that we do this reporting is so that we can better manage the business and learn from events such as this."
The name of the pilot and the London hotel were blacked out in the CAA report.