Aviation Accident Summaries

Aviation Accident Summary CHI98IA167

WASHINGTON, DC, USA

Aircraft #1

N951U

McDonnell Douglas MD82

Analysis

The Douglas MD82 experienced a flight control malfunction after takeoff and diverted to Dulles International Airport. The crew reported that they lost the autopilot, there were in-flight kicks on the rudder and the rudder tab was moving uncommanded on the ground. The Yaw Damper Actuator, Digital Flight Guidance Computer, and Dual Axis Accelerometer were removed for further testing. The Yaw Damper Actuator and the Digital Flight Guidance Computer passed testing. The Dual Axis Accelerometer was bench tested using test manual #22-19-01, Rev 1 at the avionics test center. The unit failed an original test and failed a second test after a metal sliver imbedded in the pins was removed.

Factual Information

On April 11, 1998, at 0645 est, N951U, a McDonnell Douglas MD82, being operated as Trans World Airlines flight number 235, from Washington National Airport to Saint Louis, Missouri, experienced a flight control malfunction after takeoff and diverted to Dulles International Airport. There was no damage to the aircraft and there were no injuries to the crew of 5 or 79 passengers. The flight was on an IFR flight plan and visual meteorological conditions prevailed. The crew reported that they lost the autopilot, there were inflight kicks on the rudder and the rudder tab was moving uncommanded on the ground. The aircraft was an MD-82, S/N 49245. The Yaw Damper Actuator, Digital Flight Guidance Computer, and Dual Axis Accelerometer were removed for further testing. The Yaw Damper Actuator and the Digital Flight Guidance Computer passed testing. The Dual Axis Accelerometer from the aircraft, PN 4034239-901, SN 8303033, was taken to the Honeywell Support Center in Dallas, Texas for further investigation. The part was bench tested using test manual #22-19-01, Rev 1 at the avionics test center. The unit failed an original test and failed a second test after a metal sliver imbedded in the pins was removed. See attached test report of the inspection conducted July 8, 1998.

Probable Cause and Findings

The failure of the Dual Axis Accelerometer.

 

Source: NTSB Aviation Accident Database

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