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ASN Wikibase Occurrence # 163998
Last updated: 3 May 2020
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Date:17-FEB-2014
Time:12:54
Type:Silhouette image of generic B737 model; specific model in this crash may look slightly different
Boeing 737-724
Owner/operator:United
Registration: N23708
C/n / msn: 28769/52
Fatalities:Fatalities: 0 / Occupants: 119
Other fatalities:0
Aircraft damage: None
Category:Accident
Location:near Billings, Montana -   United States of America
Phase: En route
Nature:Domestic Scheduled Passenger
Departure airport:Denver, CO (DEN)
Destination airport:Billings, MT (BIL)
Investigating agency: NTSB
Narrative:
The flight departed normally and climbed to its cruising altitude where it encountered light turbulence. The flight crew descended to a lower altitude twice in an effort to find a smooth ride. The flight encountered an area of severe mountain wave turbulence when the flight was cruising at flight level (FL) 340 in smooth air with the seat belt sign off seriously injuring two flight attendants.

According to the NTSB weather study, an Airman's Meteorological Information (AIRMET) for moderate turbulence for altitudes between FL270 and FL390 was issued at 0745 MST for a region that included the accident location. The flight dispatch release for the accident aircraft, which included weather information, included a Flight Planning Guidance product from WSI that advised of light/occasional moderate mountain wave activity between FL310 and FL390 close to where the accident occurred.

Probable Cause: an encounter with severe mountain wave turbulence during cruise flight.

Sources:

NTSB: https://www.ntsb.gov/_layouts/ntsb.aviation/brief.aspx?ev_id=20140212X03156&key=1
https://flightaware.com/live/flight/UAL1676/history/20140217/1815Z/KDEN/KBIL

Accident investigation:
cover
  
Investigating agency: NTSB
Status: Investigation completed
Duration: 6 years and 2 months
Download report: Final report


Revision history:

Date/timeContributorUpdates
19-Feb-2014 10:10 whiteshark Added
19-Feb-2014 10:11 harro Updated [Location, Narrative]
19-Feb-2014 17:19 Geno Updated [Time, Other fatalities, Location, Departure airport, Destination airport, Source]
19-Feb-2014 17:22 Geno Updated [Source]
20-Feb-2014 06:20 Whiteshark Updated [Time, Narrative]
03-Mar-2014 16:31 Geno Updated [Time, Phase, Source, Narrative]
21-Dec-2016 19:28 ASN Update Bot Updated [Time, Damage, Category, Investigating agency]
03-May-2020 18:58 ASN Update Bot Updated [Time, Operator, Departure airport, Destination airport, Source, Narrative, Accident report, ]

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