KEY POINTS:
Air New Zealand will urgently introduce new procedures for its Boeing 777s after a report found frozen jet fuel caused a British Airways plane to crash-land on approach to Heathrow Airport in London.
Boeing suggests 777 pilots be told to rev up their engines before landing to clear
ice from fuel lines and to change altitude periodically when flying through very cold air after the crash in January.
The worldwide alert covers 220 777s with Rolls-Royce Trent 800 engines in service with 11 airlines. Air New Zealand has eight of the aircraft.
Air NZ's general manager of airline operations, Captain David Morgan, said additional operational and maintenance requirements would immediately become standard operating procedure for the airline.
The British Airways plane with 152 passengers and crew crash-landed on January 17 after the engines could not provide enough thrust while approaching Heathrow Airport.
There were no deaths and no one was seriously injured, but the aircraft was destroyed. The 777 flew from Beijing through temperatures of minus 73C over Siberia, possibly thickening the fuel and reducing its flow, Britain's Air Accidents Investigation Branch said in an interim report.
"Although the exact mechanism in which the ice has caused the restriction is still unknown, it has been proven that ice could cause a restriction in the fuel-feed system," the report said. "The risk of recurrence needs to be addressed in the short term, while the investigation continues."
Boeing's initial instructions are to periodically vary altitude when fuel in the main tank is below minus 10C, and to advance the throttle to maximum for 10 seconds before the final descent when fuel has been below that temperature for more than three hours, clearing out any water build-up.
For 777 aircraft on the ground in freezing conditions, fuel pumps must be run at maximum for one minute each to prevent water build-up.
A design change would make the fuel system more "resilient", the US National Transportation Safety Board said, but such a move would take time, so interim measures were needed.
New Zealand Airline Pilots Association technical director Hugh Faris said the crash-landing was "extraordinary" for a plane with such a good reputation for reliability and safety.
Operating the aircraft in line with the directive would be "relatively straightforward".
