1989 — July 19, United Flight 232 hydraulic system failure/crash, Sioux City, IA — 112
— 112 NTSB AAR. United Airlines Flight 232…Sioux Gateway Airport… 11-1-1990, p. v.[1]
— 112 UPI. “Retired N.J. state trooper dies…crash’s 112th victim.” Daily Herald, IL, 8-21-1989.[2]
— 111 NationMaster.com, Encyclopedia, List of Notable Accidents…of Commercial Aircraft.
— 111 Associated Press. “Torn Plane.” Indiana Gazette, Indiana, PA, 7-25-1989, p. 1.[3]
— 111 AP. “United checking DC-10s in wake of crash.” Stars and Stripes (Europe), 7-24-1989, 28.[4]
—>110 AP. “Why some survived crash: Seat position….” Cedar Rapids Gazette, IA, 7-23-1989, 12A.
—>109 Associated Press. “List of dead, missing.” 7-22-1989, Cedar Rapids Gazette, IA, 13A.[5]
Narrative Information
NTSB Executive Summary: “On July 19, 1989, at 1516, a DC-10-10, N1819U, operated by United Airlines as flight 232, experienced a catastrophic failure of the No. 2 tail-mounted engine during cruise flight. The separation, fragmentation and forceful discharge of stage 1 fan rotor assembly parts from the No. 2 engine led to the loss of the three hydraulic systems that powered the airplane’s flight controls. The flightcrew experienced severe difficulties controlling the airplane, which subsequently crashed during an attempted landing at Sioux Gateway Airport, Iowa. There were 285 passengers and 11 crewmembers onboard. One flight attendant and 110 passengers were fatally injured.
“The National Transportation Safety Board determines that the probable cause of this accident was the inadequate consideration given to human factors limitations in the inspection and quality control procedures used by United Airlines’ engine overhaul facility which resulted in the failure to detect a fatigue crack originating from a previously undetected metallurgical defect located in a critical area of the stage 1 fan disk that was manufactured by General Electric Aircraft Engines.
The subsequent catastrophic disintegration of the disk resulted in the liberation of debris in a pattern of distribution and with energy levels that exceeded the level of protection provided by design features of the hydraulic systems that operate the DC-lo’s flight controls.
“The safety issues raised in this report include:
- General Electric Aircraft Engines’ (GEAE) CF6-6 fan rotor assembly design, certification, manufacturing, and inspection.
- United Airlines’ maintenance and inspection of CF6-6 engine fan rotor assemblies.
- DC-10 hydraulic flight control system design, certification and protection from uncontained engine debris.
- Cabin safety, including infant restraint systems, and airport rescue and firefighting facilities.
“Recommendations concerning these issues were addressed to the Federal Aviation Administration, the Secretary of the Air Force, the Air Transport Association and the Aerospace Industries Association. [p. v.]
“History of Flight. United Airlines (UAL) flight 232 (UA 232), a McDonnell Douglas DC-10-10,
registration No. N1819U, was a scheduled passenger flight from Stapleton International Airport, Denver, Colorado, to Philadelphia, Pennsylvania, with an en route stop at Chicago, Illinois. The flight was conducted under Title 14 Code of Federal Regulations (CFR) Part 121. Flight 232 departed Denver at 1409 central daylight time. There were 285 passengers and 11 crewmembers on board….
“About 1 hour and 7 minutes after takeoff, at 1516:10, the flightcrew heard a loud bang or an explosion, followed by vibration and a shuddering of the airframe. After checking the engine instruments, the flightcrew determined that the No. 2 aft (tail-mounted) engine had failed…The captain called for the engine shutdown checklist. While performing the engine shutdown checklist, the second officer (flight engineer) observed that the airplane’s normal systems hydraulic pressure and quantity gauges indicated zero.
“The first officer advised that he could not control the airplane as it entered a right descending turn. The captain took control of the airplane and confirmed that it did not respond to flight control inputs. The captain reduced thrust on the No. 1 engine, and the airplane began to roll to a wings-level attitude.
“The flightcrew deployed the air driven generator (ADG), which powers the No. 1 auxiliary hydraulic pump, and the hydraulic pump was selected “on.” This action did not restore hydraulic power.
“At 1520, the flightcrew radioed the Minneapolis Air Route Traffic Control Center (ARTCC) and requested emergency assistance and vectors to the nearest airport. Initially, Des Moines International Airport was suggested by ARTCC. At 1522, the air traffic controller informed the flightcrew that they were proceeding in the direction of Sioux City; the controller asked the flightcrew if they would prefer to go to Sioux City. The flightcrew responded, “affirmative.” They were then given vectors to the Sioux Gateway Airport (SUX) at Sioux City, Iowa….
“Fuel was jettisoned to the level of the automatic system cutoff, leaving 33,500 pounds. About 11 minutes before landing, the landing gear was extended by means of the alternate gear extension procedure.
“The flightcrew said that they made visual contact with the airport about 9 miles out. ATC had intended for flight 232 to attempt to land on runway 31, which was 8,999 feet long. However, ATC advised that the airplane was on approach to runway 22, which was closed, and that the length of this runway was 6,600 feet. Given the airplane’s position and the difficulty in making left turns, the captain elected to continue the approach to runway 22 rather than to attempt maneuvering to runway 31…. [pp. 1, 3-4]
“During the final approach, the captain recalled getting a high sink rate alarm from the ground proximity warning system (GPWS). In the last 20 seconds before touchdown, the airspeed averaged 215 KIAS, and the sink rate was 1,620 feet per minute. Smooth oscillations in pitch and roll continued until just before touchdown when the right wing dropped rapidly. The captain stated that about 100 feet above the ground the nose of the airplane began to pitch downward. He also felt the right wing drop down about the same time. Both the captain and the first officer called for reduced power on short final approach.
“The check airman said that based on experience with no flap/no slat approaches he knew that power would have to be used to control the airplane’s descent. He used the first officer’s airspeed indicator and visual cues to determine the flightpath and the need for power changes. He thought that the airplane was fairly well aligned with the runway during the latter stages of the approach and that they would reach the runway. Soon thereafter, he observed that the airplane was positioned to the left of the desired landing area and descending at a high rate. He also observed that the right wing began to drop. He continued to manipulate the No. 1 and No. 3 engine throttles until the airplane contacted the ground. He said that no steady application of power was used on the approach and that the power was constantly changing. He believed that he added power just before contacting the ground.
“The airplane touched down on the threshold slightly to the left of the centerline on runway 22 at 1600. First ground contact was made by the right wing tip followed by the right main landing gear. The airplane skidded to the right of the runway and rolled to an inverted position. Witnesses observed the airplane ignite and cartwheel, coming to rest after crossing runway 17/35. Firefighting and rescue operations began immediately, but the airplane was destroyed by impact and fire….
“*One passenger died 31 days after the accident as a result of injuries he had received in the accident. In accordance with 49 CFR 830.2, his injuries were classified “serious.”” [p. 5.] (NTSB AAR. United Airlines Flight 232, McDonnell Douglas DC-10-10, Sioux Gateway Airport, Sioux City, Iowa, July 19, 1989 (NTSB/AAR-90/06). Washington, DC: NTSB, 11-1-1990.)
NationMaster.com: “United Airlines Flight 232 was a scheduled flight operated by United Airlines between Denver and Philadelphia via Chicago. On July 19, 1989, the Douglas DC-10 (Registration N1819U) suffered an uncontained failure of its number 2 engine (mounted in the tail), which destroyed all three of the aircraft’s hydraulic systems….
“Captain Alfred C. Haynes and his flight crew (First Officer William Records, who was flying, and Second Officer Dudley Dvorak, flight engineer) felt a jolt going through the aircraft, and warning lights showed that the autopilot had disengaged, and the tail-mounted number two engine was malfunctioning. The co-pilot noticed that the airliner was off course, and moved his control column to correct this, but the plane did not respond. The flight crew discovered that the pressure gauges for each of the three hydraulic systems were registering zero, and they realized that the initial failure had left all control surfaces immovable. The three hydraulic systems were separated such that a single event in one system would not disable the other systems, but beyond that there was no backup system, a fact which the NTSB later recommended be remedied.
”The plane had a continual tendency to turn right, and was difficult to maintain on a stable course. It began to slowly oscillate vertically in a phugoid cycle, which is characteristic of planes in which hydraulic power is lost. With each iteration of the cycle the aircraft lost approximately 1500 feet of altitude. Dennis E. Fitch, a DC-10 flight instructor, was deadheading as a passenger on the plane and offered his assistance. After entering the cockpit, Fitch discovered that the only available method of controlling the aircraft was through adjusting the throttles of the remaining two engines; running one engine faster than the other to turn the plane (differential thrust), and accelerating or decelerating in order to gain or lose altitude. Using this method, it was possible to mitigate the phugoid cycle and make rough steering adjustments. At one point Fitch manually lowered the landing gear in flight, hoping that this would force trapped hydraulic fluid back into the lines allowing some movement of control surfaces. Although the gear lowered successfully, there was no improvement in control response as all the fluid had been lost through the punctured lines…. A phugoid is an aircraft motion where the vehicle pitches up and climbs, and then pitches down and descends, accompanied by speeding up and slowing down as it goes uphill and downhill. … Dennis E. Fitch (Denny Fitch) (born 1943) was the off-duty DC-10 training captain who helped captain Al Haynes save United Airlines Flight 232 when all flight controls were lost, on 19 July 1989. …
“Fitch continued to control the aircraft’s descent by adjusting engine thrust. With the loss of all hydraulics, the crew were unable to control airspeed independent from sink rate. On final descent, the aircraft was going 240 knots and sinking at 1850 feet per minute, while a safe landing would require 140 knots and 300 feet per minute. The aircraft began to sink faster while on final approach and veer to the right. The tip of the right wing hit the runway first, spilling fuel which ignited immediately. The tail section broke off from the force of the impact and the rest of the aircraft bounced several times, shedding the landing gear and engine nacelles and breaking the fuselage into several main pieces. On the final impact the right wing was sheared off and the main part of the aircraft skidded sideways, rolled over on to its back, and slid to a stop upside down on the right side of runway 22….
Killed were “110 of…285 passengers and one of the 11 crew members. 52 children, including 4 lap children, were on board the flight due to a Children’s Day promotion. 11 children, including 1 lap child, died.
“Of all of the passengers:
- 35 died due to smoke inhalation (None were in business class)
- 75 died for reasons other than smoke inhalation (17 were in business class)
- 42 were seriously injured (8 were in business class)
- 21 had minor injuries (1 was in business class)
- 12 had no injuries (None were in business class)
“The passengers who died for reasons other than smoke inhalation were seated in rows 1-4, 24-25, and 28-38. Passengers who died due to smoke inhalation were seated in rows 14, 16, and 22-30. A person assigned to 20H moved to an unknown seat and died due to smoke inhalation.
”Owing to the skill of the crew and a DC-10 instructor pilot, 175 passengers and 10 crew members survived the crash, which is considered a textbook example of successful Crew Resource Management, due to the effective use of all the resources available aboard the plane for help during the emergency.” (NationMaster.com, Encyclopedia, “United Airlines Flight 232.”)
Sources
Associated Press. “List of dead, missing.” 7-22-1989, Cedar Rapids Gazette, IA, 13A. Accessed 6-18-2016 at: http://newspaperarchive.com/us/iowa/cedar-rapids/cedar-rapids-gazette/1989/07-22/page-12?tag
Associated Press. “Torn Plane.” Indiana Gazette, Indiana, PA, 7-25-1989, p. 1. Accessed 6-18-2016 at: http://newspaperarchive.com/us/pennsylvania/indiana/indiana-gazette/1989/07-25?tag
Associated Press. “United checking DC-10s in wake of crash.” Stars and Stripes (Europe), 7-24-1989, p. 28. Accessed 6-18-2016 at: http://newspaperarchive.com/de/hesse/darmstadt/european-stars-and-stripes/1989/07-24/page-33?tag
Associated Press. “Why some survived crash: Seat position and blind luck.” Cedar Rapids Gazette, IA, 7-23-1989, 12A. Accessed 6-18-2016 at: http://newspaperarchive.com/us/iowa/cedar-rapids/cedar-rapids-gazette/1989/07-23/page-12?tag
National Transportation Safety Board. 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). Washington, DC: NTSB, 11-1-1990, 129 pages. Accessed 6-17-2016 at: http://libraryonline.erau.edu/online-full-text/ntsb/aircraft-accident-reports/AAR90-06.pdf
NationMaster.com. Encyclopedia. “List of Notable Accidents and Incidents on Commercial Aircraft.” Accessed 12-15-2008 at: http://www.nationmaster.com/encyclopedia/List-of-notable-accidents-and-incidents-on-commercial-aircraft [Site no longer active.]
NationMaster.com. Encyclopedia. “United Airlines Flight 232.” Accessed 12-15-2008 at: http://www.nationmaster.com/encyclopedia/United-Airlines-Flight-232
United Press International. “Retired N.J. state trooper dies, becomes crash’s 112th victim.” Daily Herald, IL, 8-21-1989. Accessed 6-18-2016 at: http://newspaperarchive.com/us/illinois/arlington-heights/daily-herald-suburban-chicago/1989/08-21/page-372?tag
[1] On page 5, after noting 111 fatalities in the crash, the NTSB notes “One passenger died 31 days after the accident as a result of injuries he had received in the accident. In accordance with 49 CFR 830.2, his injuries were classified ‘serious.’” There were 40 other serious injuries amongst the passengers and six from the crew.
[2] Notes that Harlon ‘Gerry’ Dobson, 46, of Pittsgrove, N.J. died at 7:55 p.m. Saturday [Aug 19] at the Crozer-Chester Medical Center in Chester, Pa.”
[3] “The death toll from the crash reached 111 Monday [July 24] when Brent Bealer, 28, of Quakertown, Pa. died…”
[4] “The search for victims of the crash ended Saturday with the death toll still not firm. One city official put the figure at 110, with the National Transportation Safety Board put it al 111. A list compiled by the Associated Press from names supplied by United Airlines and family, friends and employers of the victims put the toll at 111 dead or missing. Estimates of the number on board have been put at 295 and 297. A doctor at one of the hospitals treating the injured said that more patients could die….[nine in critical condition]. All four members of the flight crew, including one off-duty pilot who left his cabin seat to help control the plane, were being treated…their injuries were not critical….” (A problem with the tally of passengers had to do with non-paying lap children.)
[5] Notes a number of missing passengers as well.