NTSB Identification: CHI00IA152.
The docket is stored in the Docket Management System (DMS). Please contact Records Management Division
Scheduled 14 CFR UNITED AIR LINES, INC.
Incident occurred Wednesday, June 07, 2000 in LAFAYETTE, IN
Probable Cause Approval Date: 09/06/2001
Aircraft: Boeing 767-222, registration: N603UA
Injuries: 165 Uninjured.

NTSB investigators used data provided by various sources and may have traveled in support of this investigation to prepare this aircraft incident report.

The captain said that while in cruise flight, "...the center autopilot made an uncommanded disconnect." He said that he took control of the aircraft and found that the rudder and elevator systems appeared to be functioning normally but "...the control wheel was jammed in the straight and level position." He said that approximately 15 pounds of force was applied in order to free the control wheel. The flight was diverted and an uneventful landing was made. A postaccident examination revealed that the wheel well canted pressure deck drain lines were obstructed by debris. A Boeing service bulletin was found that recommends changes to the drain system to "...help ensure that fluid entering the canted pressure deck area will be drained out of the airplane and not leak into the wheel well area where it could freeze on the aileron control cables..." The aircraft arrived at JFK on June 6, 2000 at 1956 eastern daylight time. Weather reports for the JFK airport show rain during the night of June 6, 2000 and during the morning of June 7, 2000.

The National Transportation Safety Board determines the probable cause(s) of this incident to be:

The blocked drain lines in the canted pressure deck and the frozen aileron cable.

Full narrative available

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