Loss of control Accident Boeing 737-222 N9031U, Friday 8 December 1972
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Date:Friday 8 December 1972
Type:Silhouette image of generic B732 model; specific model in this crash may look slightly different    
Boeing 737-222
Owner/operator:United Airlines
Registration: N9031U
MSN: 19069/75
Year of manufacture:1968
Total airframe hrs:7247 hours
Engine model:Pratt & Whitney JT8D-7B
Fatalities:Fatalities: 43 / Occupants: 61
Other fatalities:2
Aircraft damage: Destroyed, written off
Location:2 km from Chicago-Midway Airport, IL (MDW) -   United States of America
Phase: Approach
Nature:Passenger - Scheduled
Departure airport:Washington-National Airport, DC (DCA/KDCA)
Destination airport:Chicago-Midway Airport, IL (MDW/KMDW)
Investigating agency: NTSB
Confidence Rating: Accident investigation report completed and information captured
The aircraft, named "City of Lincoln", took off from Washington-National Airport as United flight 553 to Chicago and Omaha. Departure time was 12:50 CST. Chicago ARTCC cleared the crew to descend to 4000 feet and the flight was given vectors for a Midway Airport runway 31L localizer course. At 14:19 the flight was transferred to Chicago Approach Control which later requested UA553 to slow down to 180 knots and later down to 160 knots. After issuing a descent clearance down to 2000 feet at 14:23 the controller requested the flight to slow down to approach speed because of separation between UA553 and a preceding Aero Commander. At 14:24 the Aero Commander passed the Outer Marker and was cleared to land on runway 31L. Two minutes later UA553 passed the Outer Marker inbound. Then, at 14:27:04 the air traffic controller decided to issue a missed approach clearance: "United 553 execute a missed approach make a left turn to a heading of 180 climb to 2000". At the same time, having just reached 1000 feet, the stick shaker suddenly activated. Full power was applied and the gear was retracted in an attempt to execute a missed approach. The Boeing continued to descend however, attaining a high nose up attitude (of at least 30deg, according to some survivors). The aircraft then clipped a tree and impacted trees, houses, utility pole cables and garages before coming to rest. Post crash fire destroyed part of the fuselage.

PROBABLE CAUSE: "The captain's failure to exercise positive flight management during the execution of a non-precision approach, which culminated in a critical deterioration of airspeed into the stall regime where level flight could no longer be maintained."

Accident investigation:
Investigating agency: NTSB
Report number: DCA73A0003
Status: Investigation completed
Duration: 8 months
Download report: Final report




  • 16th worst accident in 1972
  • 34th worst accident of this aircraft type
  • worst accident of this aircraft type at the time



photo (c) J. Douglas Scroggins III; 2 km from Chicago-Midway, IL; 08 December 1972

Revision history:


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