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NTSB Initial
Assessment OF United Airlines Flight 497, Smoke In The Cockpit |
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April 9, 2011 - The National
Transportation Safety Board continues to make progress
in its investigation of United Airlines flight 497,
which returned to the airport on April 4, 2011, in The NTSB team, comprised of 3 NTSB
investigators and representatives from the designated
parties and advisors, arrived on scene April 4 to
document and examine the aircraft and retrieve the data
and voice recorders. Two other NTSB investigators,
specializing in operational factors and maintenance
factors, traveled to various locations to review
pertinent documentation and records and conduct
interviews. |
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After documenting the condition of the
equipment in the electronics bay, investigators applied limited
electrical power to various systems on the airplane. At this
time, the preliminary examination has not revealed any signs of
burning, indications of smoke or other anomalous system
findings. The NTSB operations group completed
interviews of the flight crew yesterday. The crew indicated
that, at about 4000 feet, the airplane's electronic centralized
aircraft monitoring (ECAM) system provided an autothrottle-related
message, then an avionics smoke warning message, accompanied by
instructions to land. Despite receiving this message, neither
crew member recalled smelling smoke or fumes during the flight. The captain indicated that he used the
electronic checklist for the avionics system smoke warning
indication, which included shutting down some of the airplane's
electrical system. The crew reported that the first officer's
display screens went blank, the ECAM messages disappeared, the
cockpit to cabin intercom stopped functioning, and the
air-driven emergency generator deployed. The captain said that
he took control of the airplane at this point and managed the
radios while the first officer opened the cockpit door to advise
the flight attendants of the emergency and their return to The crew also noted to investigators that
they requested runway 10 for landing, but were told the runway
was not available due to the presence of construction vehicles.
The captain said that he was able to use the airspeed,
altimeter, and attitude information on his primary flight
display during the return to the airport, and that he ordered an
evacuation after landing. |