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Usair Flight 427




US Airways Flight 427 was a commercial airline flight from Chicago 's O'Hare International Airport to Pittsburgh, Pennsylvania , with a final destination of West Palm Beach, Florida . The flight crashed on September 8 , 1994 , killing everyone on board.

On that day, the Boeing 737-3B7 , registered N513AU, was approaching runway 28R in Pittsburgh's airport, which is located in Findlay Township, Pennsylvania . At about 6,000 feet (1,830 meters) and 6 miles {10 km) from the runway, the aircraft experienced a sudden loss of control and slammed into the ground in a nearly vertical position in Aliquippa, Pennsylvania , killing all 127 passengers and 5 crew members.

After its longest investigation in history—more than four and a half years—the concluding statement said:
:The National Transportation Safety Board determines that the probable cause of the USAir flight 427 accident was a loss of control of the airplane resulting from the movement of the rudder surface to its blowdown limit. The rudder surface most likely deflected in a direction opposite to that commanded by the pilots as a result of a jam of the main rudder power control unit servo valve secondary slide to the servo valve housing offset from its neutral position and overtravel of the primary slide. {Link without Title}

The NTSB concluded that similar rudder problems caused the previously mysterious March 3 1991 crash of United Flight 585 , and the June 9 1996 incident involving Eastwind Airlines flight 517, both of which were Boeing 737s.

Other changes resulting from the investigation were:
  • to warn and train pilots of insufficient Aileron authority at an airspeed at or less than 190 knots (218 mph, 354 km/h), formerly the usual approach speed for a B737.

  • to mandate four additional channels of information in flight data recorders, pilot rudder pedal commands

  • Boeing redesigned the rudder system on 737s and retrofitted existing craft until the affected systems can be replaced

  • Congress requires airlines to do a better job dealing with families of crash victims


427 is no longer a valid flight number for any flight on US Airways' timetable.


EXTERNAL LINKS



BOOKS

  • Bill Adair, ''The Mystery of Flight 427: Inside a Crash Investigation'', ISBN 1588340058

  • Gerry Byrne, ''Flight 427: Anatomy of an Air Disaster'', ISBN 038795256X