MONTREAL, Nov. 5, 2013 /CNW/ - The Transportation Safety Board of Canada
(TSB) today released its investigation report (A10Q0213) into the 30
November 2010 runway excursion of an American Airlines Boeing 737-800
at the Montreal/Pierre Elliott Trudeau International Airport.
The aircraft was on a flight to Montreal, Quebec from Dallas, Texas with
113 people aboard. The aircraft landed normally on the wet runway in a
crosswind. As the aircraft was slowing down, it veered, un-commanded by
the crew, towards the left side of the runway. The captain, the pilot
flying, tried using the rudder and the nose wheel steering tiller to
steer the aircraft back to the runway centerline. Although the aircraft
heading started to return back towards the runway heading, the aircraft
continued to travel towards the left and exited the runway surface.
There were no injuries and damage to the aircraft was minor.
Investigators found that the un-commanded veer to the left of runway
centerline was likely due to a jam in the nose wheel steering system.
Following the occurrence, investigators did not find any anomalies with
the nose gear wheel system, as the jam likely cleared up. The flight
crew did not receive any indication that a problem existed with the
nose gear steering system, nor is there any written procedure to manage
a nose wheel steering problem of this kind. The aircraft's flight data
recorder (FDR) does not record parameters from the nose wheel steering
system, thus making it difficult to determine when and how problems
with nose wheel steering occur.
There have been 11 similar occurrences reported involving various Boeing
aircraft types in the past 21 years throughout the world. The cause of
these un-commanded nose wheel steering occurrences remains uncertain,
despite post-event examinations and other efforts to analyze them. The
manufacturer's safety review process has deemed these occurrences to be
an acceptable risk given their remoteness, and the manufacturer has not
taken further action to correct them. As their cause is uncertain and
because little is being done to better understand the problem, the
Board is concerned that there remains a risk for runway excursions to
Following the accident, American Airlines now discusses this occurrence
as part of recurrent training for its flight crews. This training is
given to the flight crews to raise awareness of the possibility of a
runway excursion due to a nose wheel steering problem after landing.
The TSB is an independent agency that investigates marine, pipeline,
railway and aviation transportation occurrences. Its sole aim is the
advancement of transportation safety. It is not the function of the
Board to assign fault or determine civil or criminal liability.
SOURCE: Transportation Safety Board of Canada
For further information:
Transportation Safety Board of Canada
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