An Air New Zealand pilot fell asleep twice while behind the controls of long-haul flight.
The pilot, who is not named, told the Civil Aviation Authority in his "fatigue report" that during a flight from London to Los Angeles in 2011 he fell into a deep sleep without warning.
He did the same again later, and decided to take an additional rest in his bunk.
Afterwards the pilot said he was able to continue to Los Angeles without incident.
The pilot blamed exhaustion resulting from bad sleep and delays. He said he had moved rooms three times in two days in London, after problems with air-conditioning at his hotel.
A 50-minute flight delay in London and a long time spent taxiing were also blamed.
The pilot's fatigue report was released to TV3 under the Official Information Act.
An Air New Zealand spokeswoman said the flight in question had three pilots on board.
"During the cruise phase of the flight, one of the two operating pilots nodded off twice for around a minute and woke spontaneously.
"The other operating pilot on the flight deck was aware of this, and safety was not compromised at any point."
Safety was "non-negotiable" for the company, and staff were encouraged to report fatigue.
- Fairfax Media