Serious incident Boeing 757-251 N516US,
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ASN Wikibase Occurrence # 373966
 
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Date:Wednesday 5 November 1986
Time:23:00 LT
Type:Silhouette image of generic B752 model; specific model in this crash may look slightly different    
Boeing 757-251
Owner/operator:Northwest Airlines
Registration: N516US
MSN: 23204/104
Year of manufacture:1986
Engine model:P&W 2037
Fatalities:Fatalities: 0 / Occupants: 188
Aircraft damage: None
Category:Serious incident
Location:Washington, DC -   United States of America
Phase: En route
Nature:Passenger - Scheduled
Departure airport:Washington-National Airport, DC (DCA/KDCA)
Destination airport:Minneapolis-St. Paul International Airport, MN (MSP/KMSP)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
Narrative:
DRG AN EN ROUTE CLIMB, AILERON CONTROL (CTL) BCM PROGRESSIVELY MORE STIFF. AT CRUISE ALT, THE AUTOPLT DISENGAGED & THE AILERONS WOULD NOT MOVE. AILERON CTL WAS RESTORED AFTER A DSCNT BELOW THE FREEZING LEVEL. THE ACFT WAS FLOWN BELOW THE FREEZING LVL FOR THE REMAINDER OF THE FLT. A POST-FLT MAINT INSPN REVEALED NO PHYSICAL EVIDENCE FOR THE TEMPORARY LOSS OF AILERON CTL. AN INVESTIGATION REVEALED THAT BEFORE TAKEOFF, THE ACFT WAS EXPOSED TO RAIN FOR ABOUT 50 MIN WHILE PARKED AT A GATE. THE TEMPERATURE IN WASHINGTON WAS IN THE MID 40'S. THE OPERATOR SUSPECTED ICE BUILD-UP ON THE AILERON CABLES. THE MANUFACTURER HAD ISSUED A SERVICE BULLETIN (SB) (SB B-757-0079) TO REMOVE THE AILERON CABLE GROMMETS & APPLYA SEALANT TO ELIMINATE THE PROBLEM. THE SB HAD BEEN COMPLIED WITH. AFTER THE INCIDENT, A REVISED SB, DATED 11/6/86, WAS ISSUED TO REPLACE THE AILERON CABLE GROMMETS WITH NEW GROMMETS WITH INCREASED INTERNAL DIAMETER. ALSO, AN OPNS MANUAL BULLETIN (NUMBER 87-1) WAS ISSUED ON 1/22/87 TO ADVISE FLT CREWS.

Probable Cause:

Accident investigation:
cover
  
Investigating agency: NTSB
Report number: CHI87IA026
Status: Investigation completed
Duration: 1 year and 5 months
Download report: Final report

Sources:

NTSB CHI87IA026

Revision history:

Date/timeContributorUpdates
27-Mar-2024 19:19 ASN Update Bot Added

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