KEY POINTS:
Air New Zealand's fleet of 777 aircraft remains in operation while British investigators rush to figure out what caused a British Airways 777-200ER to drop from the sky at Heathrow Airport last week.
Fuel contamination emerged as one of the most probable causes, according to postings on pilots' blogs and websites, although there has been no official evidence of this from any authorised sources.
The speculation is that water, which is denser than fuel, could have leaked into the fuel tank. During flight, the water could have frozen. But as the fuel warmed during the approach at lower altitude, the ice could have partially melted, leading to slush in the small amount of fuel left, and thus impeding the fuel flow.
Air New Zealand spokeswoman Tracy Palmer yesterday moved to assure the public Air New Zealand was closely following the Heathrow investigation.
But in the meantime, the airline's 777 fleet continued to fly, though safety remained a "paramount and non-negotiable" feature of its operation.
The British Airways jet suffered double engine failure as it approached the runway at the end of a flight from Beijing, in a freak accident described by aviation experts as "a million to one".
More than 150 passengers and crew were on the plane at the time.
Pilots managed a controlled crash landing, with the plane coming to rest inside the Heathrow compound, about 300m short of the runway.
The Daily Mail yesterday reported earlier theories - including that pilot error and bird strike were possible causes of the near disaster - were now considered "unlikely".
Air New Zealand operates eight 777-200s, flying long-distance to ports in North America and Asia.
The aircraft - which can seat more than 300 passengers - are an average 1.4 years old, and fly an average 14 hours a day.
One retired commercial pilot yesterday told the Herald there was little Air New Zealand could do until the results of the investigation were released.
Experts from engine builders Rolls Royce, aircraft manufacturer, Boeing, British Airways, civil aviation would all be "scouring" the crash site, he said.
"Once they establish the cause, a directive will go around to other airlines - [flying] those aircraft - warning of the problem, so checks can be carried out."
Air New Zealand yesterday refused to say whether contingency plans were in place, should the company suddenly have to ground its 777s.
Airline Pilots' Association vice-president Peter Fleming said pilots always felt a certain amount of apprehension following the crash - somewhere in the world - of an aircraft of the type they fly, chiefly because "we are the ones flying them".
Mr Fleming - an Airbus pilot - said he was "very confident" of Air New Zealand's maintenance and safety procedures.
It was understandable investigators at Heathrow were checking the quality of the fuel used by the fallen 777, as it was "one of the few elements that are common to both engines", he said. However, he said it would be "unwise" to speculate on the cause of the crash.
