Featured Map for 19 July 2019:
United Airlines Flight 232 DC-10 at Sioux City

30 years ago, on the afternoon of 19 July 1989, United Airlines flight 232 departed Denver Stapleton International Airport for Chicago O'Hare International Airport (continuing to Philadelphia). It was a warm afternoon with scattered thunderstorms over the Midwestern United States. At 3:16 pm CDT, 67 minutes into the flight, the flight crew was executing a right turn near Alta, Iowa, at a cruise altitude of 37,000 feet when they "heard a loud bang or an explosion, followed by vibration and a shuddering of the airframe." Engine instrumentation indicated that the number 2 engine, a GE CF6-6D mounted in the tail of the aircraft, had failed. The flight engineer soon noticed that hydraulic pressure and quantity gauges had dropped to zero for all three of the DC-10's hydraulic systems.

With no hydraulic systems the aircraft's control surfaces remained in the configuration for a slight right turn. An emergency was declared and the crew quickly determined that their only means of controlling the aircraft was through differential thrust of the remaining two, wing-mounted engines. Captain Alfred C. Haynes, First Officer William Records, and Flight Engineer Dudley Dvorak were joined by Dennis E. Fitch, a DC-10 check captain who had been a passenger and who volunteered to help, which he did by manipulating the two throttle levers.

A United dispatcher suggested that flight 232 divert to Lincoln, Nebraska but after making multiple 360º right turns the flight attempted an emergency landing on closed runway 22 at Sioux Gateway Airport in Sioux City, Iowa. With no ability to deploy flaps the aircraft touched down fast on the threshold of runway 22, just to the left of the centerline, 44 minutes after the engine failure. The aircraft had begun another uncommanded right turn and roll at the last moment so first ground contact was made by the right wingtip followed by the right main landing gear. The aicraft rolled to an inverted position, broke up, and caught fire. Despite that, 185 of the 296 passengers and crew survived the crash. (The official fatality count is 111, consisting of 110 passengers and one crew member. One passenger died 31 days after ther accident as a result of injuries sustained in the crash but his injuries were classified as serious per 49 CFR 830.2.)

Today's Featured Map shows the approximate path of the flight path for several minutes leading to the point of engine failure in red, based on Figure 2 from the NTSB report. The report does not include the path for the first hour of the flight nor the planned route to Chicago so these are simply sketched in grey. The two diversion airports which were considered are also included.

References and additional information:

• Aircraft Accident Report: United Airlines Flight 232, McDonnell Douglas DC-10-10, Sioux Gateway Airport, Sioux City, Iowa, July 19, 1989 (NTSB/AAR-90/06) – Embry-Riddle Aeronautical University: Hunt Library (1 November 1990)
• N1819U United Airlines McDonnell Douglas DC-10-10 – Planespotters.net
• 49 CFR § 830.2 - Definitions – Cornell University Law School
  
  
• Featured Map: 40 Years Ago: American Airlines 191 DC-10 Crash (25 May 2019)
• Featured Map: Uncontained Engined Failures (8 November 2010)