45 fatalities

1972-12-08: Boeing 737-200 (N9031U) — United Airlines — Chicago-Midway, United States of America

Chicago-Midway, United States of AmericaLanding (descent or approach)

On December 8, 1972, a Boeing 737-200 (registration N9031U) operated by United Airlines was involved in an aviation accident near Chicago-Midway, United States of America during landing or approach. 45 people were killed. Investigators recorded the probable cause as: The pilot failed to manage the aircraft effectively during a non-precision approach, resulting in a loss of airspeed that led to a stall. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 2 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781233341Data APIEditorial standards
Boeing 737-200
Photo: San Diego Air & Space Museum Archives / Public domain, via Wikimedia Commons

A Boeing aircraft crashed during an attempted missed approach at Chicago Midway Airport after experiencing a loss of airspeed and a subsequent stall.

What happened

On the afternoon of the accident, United Airlines flight UA553 departed from Washington-National Airport, bound for Omaha with a scheduled stop at Chicago-Midway Airport. During the approach to Midway, the crew received instructions from Chicago ARTCC to descend to 4000 feet and was provided vectors for the runway 31L localizer course. As the flight transitioned to Chicago Approach Control, controllers issued several speed reductions, first to 180 knots and subsequently to 160 knots. Following a descent clearance to 2000 feet, the controller requested further deceleration to approach speed to maintain separation from a preceding Aero Commander.

While the preceding aircraft cleared the Outer Marker for landing, UA553 passed the same marker approximately two minutes later. At 14:27:04, air traffic control instructed the crew to execute a missed approach, directing a left turn to a heading of 180 and a climb to 2000 feet. As the Boeing aircraft reached an altitude of 1000 feet, the stick shaker activated, indicating an imminent stall. In response, the crew applied full power and retracted the landing gear to attempt the missed approach procedure. Despite these efforts, the aircraft continued to lose altitude and entered a high nose-up attitude of at least 30 degrees. The aircraft subsequently struck trees, utility cables, houses, and garages before coming to a stop, with a post-crash fire causing significant damage to the fuselage.

Findings

The investigation determined that there were zero survivors of the impact. The accident was driven by the pilot's failure to maintain proper flight management during the non-precision approach, which led to a critical drop in airspeed and an unrecoverable stall.

Probable cause

The pilot failed to manage the aircraft effectively during a non-precision approach, resulting in a loss of airspeed that led to a stall.