There was nothing to suggest the actions of an engineer who
checked the engine of an Air New Zealand 747 after it caught
fire as it approached San Francisco were inappropriate, an
investigation has found.
The Air New Zealand Boeing 747-419, was on approach to land
at San Francisco on September 16, 2011 when the crew was
alerted by the crew of another aircraft that flames were
coming from the No 4 engine.
There was no indication on the Air New Zealand flight deck of
the fire, the Transport Accident Investigation Commission
(TAIC) said in its report today.
After an uneventful landing and shutdown, a local engineer
inspected the engine and carried out some checks before
releasing the aeroplane back to service.
The aeroplane completed a further two sectors without
incident but on the next, on approach to Auckland, the No 4
engine surged and it was shut down.
The plane landed safely on three engines.
The cause of the surge at Auckland was not identified and it
could not be determined whether the San Francisco fire
contributed to the more severe occurrence at Auckland.
"The actions of the San Francisco engineer in following the
prescribed maintenance procedures, and completing some
additional checks before releasing the aeroplane back to
service, were considered appropriate," the TAIC said.
"Engine compressor stalls and surges can be dramatic,
especially for passengers. However, a review by Rolls-Royce
of reported RB211 engine surge events showed that while a
stall could result in damage or having to shut down the
engine, the safe operation of the aeroplane should not be
affected. In both incidents the crews acted correctly in
dealing with the surges."
The TAIC said it became aware of another two recent engine
failure/shutdown occurrences in Air New Zealand's fleet.
Although they involved different aeroplane types, each, like
the Boeing 747, had been scheduled for replacement in the
short to medium future.
The inquiry found no link between the three engine
occurrences and nothing to suggest that the operator was
accepting lower engineering or safety standards as the three
aeroplane types neared replacement.