American Airlines Flight 191

American Airlines Flight 191

230px Flight 191 in an unrecoverable bank moments before the crash. Its No. 1 engine had been severed on the runway.
Summary
Date	May 25, 1979
Type	Metal fatigue
Site	Chicago, Illinois
Passengers	258
Crew	13
Injuries	2 (on ground)
Fatalities	273 (2 on ground)
Survivors	0
Aircraft type	McDonnell Douglas DC-10-10
Operator	American Airlines
Tail number	N110AA
Flight origin	O'Hare International Airport
Destination	Los Angeles International Airport

American Airlines Flight 191 was a flight to Los Angeles International Airport from O'Hare International Airport in Chicago, Illinois. On May 25, 1979, the McDonnell Douglas DC-10-10 aircraft on the route crashed at around 15:04 CDT after taking off from O'Hare with 271 passengers and crew onboard, all of whom were killed, along with two people on the ground. In terms of all individuals killed, Flight 191 was the deadliest airplane crash incident on U.S. soil until the four deliberate crashes of the September 11, 2001 attacks. In terms of the total number of aircraft occupants killed, it remains (as of March 2008) the deadliest aircraft crash on U.S. soil (followed by American Airlines Flight 587).

Prequel

The weather was clear, with the wind Northeast at 22 knots. At O'Hare Airport in Chicago, one of the world's busiest, traffic was heavy but normal for a Friday afternoon which marked the beginning of a Memorial Day weekend.

The DC-10, displaying registration N110AA, was a modern and proven model, having entered service some eight years earlier. The aircraft itself, version DC10-10, was one of the largest models in commercial service, seating 270 passengers in a mixed class configuration. It had been delivered new to American Airlines on February 25, 1972. Just over 7 years old, it had logged over 20,000 trouble-freeTemplate:Fact hours of flight since it had been built by McDonnell Douglas.

Aboard were 271 people, including flight and cabin crews. Among the passengers were a number of Chicago literary figures on the way to an annual booksellers convention in Los Angeles.

Flight and cabin crew

The captain was veteran Walter Lux, 53. His first officer was James Dillard, 49, and the flight engineer was Alfred Udovich, 56. Captain Lux was a 22,000 hour pilot who had been flying the DC-10 models since their introduction into service eight years before. First Officer Dillard and Flight Engineer Udovich were also experienced, with nearly 25,000 flight hours between them. A cabin crew staff of 10 persons attended to the passengers.

Accident

At 2:50 PM CDT, N110AA was cleared to taxi to runway 32R (Right) and at 3:02 PM, the flight was cleared for takeoff and began its roll down the runway.

Shortly before the takeoff rotation began, with 6,000 feet of runway covered, air traffic controller Ed Rucker witnessed the number one engine (left wing) separate from the aircraft and fly up and over the wing to crash onto the runway. The aircraft continued in a normal climb momentarily to around 350 feet (AGL), as fuel and leaking hydraulic fluid spewed in a vapor trail behind the plane. Such an incident is theoretically survivable in a DC-10; the shift in center of gravity and mean aerodynamic chord were within tolerances, and the aircraft could have landed safely if the engine loss had not caused other failures. In subsequent flight simulation testing, only pilots who were aware of Flight 191's specific problems were able to recover successfully from the stall.

File:AA191-crash-site.png

Flight 191's final resting place. Damaged mobile homes can be seen to the right.

The pilots aimed to reduce speed from 165 knots to the recommended engine-out climb speed of 153 knots, but the engine separation had severed the hydraulic lines that controlled the aircraft's leading-edge wing slats (retractable devices that decrease a wing's stall speed during takeoff and landing). Further, the missing engine supplied the electricity to the captain's instruments — notably stall warning, slats disagreement, and stick shaker, which were only available to the captain and not replicated in the first officer's instruments. To reach a backup power switch, the flight engineer would have needed to rotate his seat, release his safety belt and stand up, part of the abnormal situation routines, not the take-off emergency procedure. This meant that the pilots were unaware of the aircraft's true configuration. DC-10 aircraft engines are not visible from the cockpit windows, and the control tower did not inform the flight crew of what they had seen.

As the hydraulic fluid bled away, the slats retracted on the left wing, raising that wing's stall speed from 124 knots to around 160 knots, resulting in a significant loss of lift. As the pilots slowed the aircraft, the left wing stalled. With the right wing still providing lift, the aircraft quickly entered an uncontrollable 112-degree left bank and pitched below the horizon from around 325 feet, slamming into an open field approximately 4,600 ft from the end of the runway northwest of the airport at 15:04 CDT after about 31 seconds in the air.

The plane struck a hangar of the old Ravenswood Airport which was in use by the Courtney-Velo Excavating Company at 320 W Touhy Avenue, with the fuselage cutting a trench into the empty former airfield to the east of a mobile home park. With a full load of highly volatile jet fuel, the crash generated a huge fireball, causing a plume of smoke so large it could be seen from the downtown Chicago Loop. The aircraft disintegrated and burned, and all 271 people on board were killed during the impact and explosion, which also killed two workers at the Courtney-Velo repair garage and severely burned two more. Some wreckage was thrown into the nearby mobile home park, where three residents were injured and five trailers and several automobiles were damaged.

Cockpit recorder, air traffic controller

Although the plane's cockpit voice recorder was powered by the severed number #1 engine, it picked up one of the crew saying "..Damn.." before recording ceased. The control tower voice recorder recorded a controller contacting the airliner when he witnessed the engine separation just after take-off, but the crew didn't answer as they were too busy trying to save the aircraft. The recording begins with the controller talking without transmitting on the frequency: "Look at this, look at this, he blew off an engine. Equipment, I need equipment, he blew an engine. Oh, shit." The controller then transmitted, "And American one, uh, ninety-one heavy, you wanna come back and to what runway?" Without keying the mic, the controller can be heard: "He's not talkin' to me ...yeah, he's gonna lose a wing. There he goes, there he goes..." Another controller in the tower remarked, "I need to be relieved."

Witnesses, media response

The disaster and investigation was quickly and thoroughly covered by the media assisted by new news gathering technologies. The public impact of the accident was increased by dramatic amateur photos taken of the incident, which were published on the banner of the Chicago Tribune the following day.

At the time, American Airlines allowed passengers to watch their aircraft takeoffs and landings on board the aircraft on closed-circuit television. It is not known whether passengers were able thus to see the crash occurring. Michael McLaughlin from Toronto filmed the flight and crash through a window at the O'Hare terminal.

Officials at the destination airport, Los Angeles International, were careful to keep the arriving news media away from passenger relatives who were waiting for Flight 191.

There were some early reports that a collision of a small plane had been involved in the crash. This apparently resulted from the discovery of small aircraft parts among the wreckage at the crash site. The parts were determined to have originated on the ground from the former Ravenswood Airport, a former general aviation facility which had been out of service for a few years. An owner there had been selling used aircraft parts from the former hangar building.

NTSB investigation

File:DC-10 engine-pylon.svg

An FAA diagram of the DC-10 engine and pylon assembly indicating the failed aft pylon attach fitting.

The crash of flight 191 brought fierce criticism from the media because it was the fourth fatal accident involving a DC-10 at the time. 622 people had died in DC-10 accidents, including flight 191. As the weather was perfect for flying and there was no indication that a flock of birds or another plane caused the crash, the remains of engine #1 raised serious concerns of the safety of the DC-10. The separated engine was not the only concern, as the public wanted to know whether the detached engine was the only cause of the crash. Investigators wondered if a fire was possibly the cause, as this was backed up by testimony from air traffic controller Ed Rucker who said he saw a 'flash' from the wing. This raised concerns that 191 was the result of a terrorist attack. Sixty witnesses who saw the plane on the runway ruled out a bomb, as they all saw engine #1 swing forward then flip up and over the top of the wing, which pointed to structural failure as the cause.

The findings of the investigation by the National Transportation Safety Board (NTSB) were released on December 21, 1979. It revealed the probable cause to be attributable to damage to the left wing engine pylon that occurred during an earlier engine change at American Airlines's aircraft overhaul facility in Tulsa, Oklahoma. Evidence came from the flange, a critical part of the pylon assembly. It was revealed to be damaged before the crash, and investigators looked at the plane's maintenance history and found it was serviced eight weeks before the crash. The pylon was damaged due to an ill-thought-out engine removal procedure. The original procedure called for removal of the engine prior to the removal of the engine pylon. To save time and costs, American Airlines, without the approval of McDonnell Douglas, had begun to use a faster procedure. They instructed their mechanics to remove the engine with the pylon all together as one unit. A large forklift was used to support the engine while it was being detached from the wing. This procedure was extremely difficult to execute successfully, due to difficulties with holding the engine assembly straight while it was being removed.

This method of engine-pylon removal was used to save man hours and was encouraged despite differences with the manufacturer's specifications on how the procedure was supposed to be performed. The accident investigation also concluded that the design of the pylon and adjacent surfaces made the parts difficult to service and prone to damage by maintenance crews. According to the History Channel, United Airlines and Continental Airlines were also using a one-step procedure. After the accident, cracks were found in the bulkheads of DC-10s in both fleets.

The procedure used for maintenance did not proceed smoothly. If the forklift was in the wrong position, the engine would rock like a see-saw and jam against the pylon attachment points. The forklift operator was guided by hand and voice signals; the position had to be spot-on or could cause damage, but management was unaware of this. The modification to the aircraft involved in flight 191 didn't go smoothly; engineers started to disconnect the engine and pylon but changed shift halfway through; when work continued, the pylon was jammed on the wing and the forklift had to be re-positioned. This was important evidence because, in order to disconnect the pylon from the wing, a bolt had to be removed so that the flange could strike the clevis. The procedure used caused an indentation that damaged the clevis pin assembly and created an indentation in the housing of the self-aligning bearing, which in turn weakened the structure sufficiently to cause a small stress fracture. The fracture went unnoticed for several flights, getting worse with each flight that the plane had taken. During flight 191's takeoff, enough force was generated to finally cause the pylon to fail. At the point of rotation, the engine detached and was flipped over the top of the wing.

The loss of the engine by itself should not have been enough to cause the accident. During an interview on Seconds From Disaster, Former NTSB investigator Michael Marx mentioned there were other incidents where the engine fell off, yet they landed without incident. Flight 191 would have been perfectly capable of returning to the airport using its remaining two engines, as the DC-10 is capable of staying airborne with any single engine out of operation. Unfortunately, several other factors combined to cause a catastrophic loss of control.

The separation of the engine severed electrical wiring and hydraulic lines which were routed through the leading edge of the wing. The damage to the lines caused a loss of hydraulic pressure, which in turn led to uncommanded retraction of the outboard slats in the port wing. The DC-10 design included a back-up hydraulic system which should have been enough to keep the slats in place; however, both lines are too close together, a design also used on the DC-9. There should have been enough fluid to keep the slats extended, so investigators wanted to know why they were never re-extended by the pilot. The answer came from the end of the recording on the CVR. The number 1 engine powered both the recorder and the slat warning system, which left the pilot and co-pilot with no way of knowing about the position of the slats. Investigators examined the FDR to see what occurred after the engine detached. The procedure called for the captain to go to V2 which he did perfectly, but investigators found that it said nothing about incidents where the speed was already above V2, as it was in this case. Therefore, the pilot had to reduce speed. Simulator tests were done to see if this made a difference; 13 pilots followed the procedure 70 times and not one was able to recover. The NTSB concluded that reducing speed when the slats are back may actually have made it more difficult for the pilot to recover control of the aircraft. When a DC-10 is about to stall it gives two warnings: The first is the stick-shaker which causes the yoke to vibrate, and the second is a warning light that flashes. These combined warnings should have alerted the pilots to increase speed immediately. American Airlines had chosen to have the stick-shaker on the pilot's side only, but the stick-shaker did not operate because it was powered by the missing left engine. In the event of an engine failure, it is possible for the flight engineer to switch the pilot's controls to a backup power supply. However, investigators determined that in order for him to access the necessary switch, the engineer would have had to unfasten his seat belt, stand up, and turn around.

The DC-10 hit the ground with a bank of 112°, and at a nose-down attitude of 21°. The NTSB concluded that given the circumstances of the situation, the pilots could not be reasonably blamed for the resulting accident.

In his book Blind Trust, John J. Nance argues that the 1978 Airline Deregulation Act caused havoc and induced cost-cutting in the industry, producing a serious erosion of the margin of safety for passengers. Nance argues that the industry "reverted from an industry under partial surveillance to an industry running on the honor system".

Warnings from the maintenance team

One of the maintenance workers, Joe White was concerned about the maintenance procedures, but his warnings were not taken seriously by management.Template:Fact

Aftermath

File:AA191-responders.png

First responders survey the Flight 191 crash site in Des Plaines, Illinois.

Problems with DC-10s were discovered as a cause of the accident, including deficiencies in both design specifications and maintenance procedures which made damage very likely. Since the crash happened just before a Western Airlines DC-10 crashed in Mexico City and six years after a Turkish Airlines DC-10 crashed near Paris, the FAA quickly ordered all DC-10s to be grounded until all problems were solved. The result of the problem-solving was an arguably more efficient and safe DC-10.

The US government fined American Airlines $500,000 for improper maintenance procedures, but the insurance settlement for the replacement of the aircraft gave American Airlines $25,000,000 beyond the fine amount.Template:Fact

Although the company's employees participated in an "I'm proud of the DC-10" campaign, McDonnell Douglas shares fell more than 20% following the crash of Flight 191. The DC-10 itself had a bad reputation, but ironically it was often caused by poor maintenance procedures, and not design flaw. In 1997 the McDonnell Douglas company was taken over by its rival, Boeing, which moved its corporate headquarters from Seattle to Chicago.

Despite the safety concerns, the DC-10 went on to outsell its closest competitor, the Lockheed L-1011, by nearly 2 to 1. This was due to the L-1011's launch being delayed and the DC-10 having a greater choice of engines (the L-1011 was only available with Rolls-Royce engines, while the DC-10 could be ordered with General Electric or Pratt & Whitney engines).

Victims

Itzhak Bentov, the celebrated biomedical inventor (the cardiac catheter), New Age author (Stalking the Wild Pendulum and A Cosmic Book) and kundalini-researcher died in the crash.

Judith Wax perished along with her husband, Sheldon Wax. Judith Wax frequently contributed to Playboy (of which Sheldon was managing editor), notably the annual "Christmas cards" piece that "presented" short satirical poems to various public figures. It was reported at the time that in her 1979 book Starting in the Middle, she had talked about her fear of flying. The magazine's fiction editor Vicki Haider also lost her life in the crash.

Several members of the American Booksellers Association on their way to its annual convention at the Los Angeles Convention Center, where they were to have a joint party organized by Playboy founder Hugh Hefner, died in the crash.

Several senior executives of the accounting firm Coopers & Lybrand died on the plane.

Actress Cyd Charisse's daughter-in-law, Sheila Charisse, died in the crash.

Close calls

Power-pop band Shoes were also scheduled to be on the flight, but at the last minute switched to another flight scheduled for the following Tuesday. [1]

History and media

The cable/satellite TV channel The History Channel produced a documentary on the crash.

The episode from Seconds From Disaster titled "Chicago Plane Crash" (also known as "Flight Engine Down") detailed the crash of Flight 191 and included footage of the investigation press conferences.

Following the crash and the media attention towards the DC-10, American Airlines replaced all "DC-10 LuxuryLiner" titles with a more generic "American Airlines LuxuryLiner".

See also

• List of accidents and incidents on commercial airliners
• El Al Flight 1862
• Delta Air Lines Flight 191
• Air safety

External links

• NTSB (National Transportation Safety Board) Report (pdf)
• Aviation-Safety.net report on the disaster
• FAA "Public Lessons Learned from Accidents -American Airlines Flight 191"
• Article on a journalist's investigation of DC-10 aircraft and the Flight 191 crash
• Ghost of the Prairie - Lingering Spirits of Flight 191
• PlaneCrashInfo.Com - American Airlines Flight 191
• Chicago Public Library article on Flight 191
• Flight 191 Remembered (FOX Chicago website)
• Pre-crash pictures from Airliners.net

Template:Seconds From Disaster