Accident Boeing 737-322 N313UA, Monday 31 July 2000
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Date:Monday 31 July 2000
Time:23:15 LT
Type:Silhouette image of generic B733 model; specific model in this crash may look slightly different    
Boeing 737-322
Owner/operator:United Airlines
Registration: N313UA
MSN: 23674/1481
Year of manufacture:1987
Total airframe hrs:39238 hours
Engine model:Cfm CFM56-3C-1
Fatalities:Fatalities: 0 / Occupants: 118
Other fatalities:0
Aircraft damage: None
Location:CHICAGO, IL -   United States of America
Phase: Unknown
Nature:Passenger - Scheduled
Departure airport:BOSTON, MA (KBOS)
Destination airport:Chicago-O'Hare International Airport, IL (ORD/KORD)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
A passenger sustained a serious in-flight injury during an evasive maneuver following a Traffic Alert and Collision Avoidance System (TCAS) warning approximately 20 minutes prior to landing. The weather did not support the presence of clear air turbulence. In a written statement, the copilot stated, "However, shortly thereafter while continuing our descent into Chicago, the Traffic Alert and Collision Avoidance System (TCAS) alerted us to a potential conflict with an aural 'TRAFFIC, TRAFFIC' warning, the EHSI [Electronic Horizontal Situation Indicator] displayed a visual warning as well. ... Almost immediately after the initial Traffic Advisory (TA), a subsequent 'CLIMB, CLIMB, CLIMB' aural warning was issued at approximately 14,000 feet as well as visual warnings on the EHSI and the EADI [Electronic Attitude Director Indicator]. ... The TCAS Resolution Advisory 'RA' commanded a pitch attitude of approximately 5 degrees nose up. Within one minute the TCAS 'CLEAR OF CONFLICT' aural warning was issued and the captain reestablished a descent while I notified ATC [Air Traffic Control] of the RA and our resumption of the descent. ... The captain contacted the flight attendants to ascertain the condition of the passengers and cabin crew. He was informed that one passenger hurt his ankle during the avoidance maneuver, but was not in need of immediate medical assistance." The doctor who treated the passenger stated, "Radiographs were take[n] 01 August 2000 and were significant for a left fibular fracture."

Probable Cause: the evasive maneuver performed by the pilot. A factor was the activation of the collision avoidance system.

Accident investigation:
Investigating agency: NTSB
Report number: CHI00LA269
Status: Investigation completed
Duration: 1 year and 4 months
Download report: Final report



Revision history:

25-Mar-2024 11:58 ASN Update Bot Added

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