American Airlines Flight 191 – Aviation DisasterDescriptionAmerican Airlines Flight 191 was a regularly scheduled passenger flight from O’Hare International Airport in Chicago to Los Angeles International Airport. The McDonnell Douglas DC-10-10 crashed on May 25, 1979, moments after takeoff from Chicago. All 258 passengers and 13 crew on board were killed, along with two people on the ground. It is the deadliest aviation accident to have occurred in the United States.
Investigators found that as the jet was beginning its takeoff rotation, engine number one on the left wing separated and flipped over the top of the wing. As the engine separated from the aircraft, it severed hydraulic fluid lines and damaged the left wing, resulting in a retraction of the slats. As the jet attempted to climb, the left wing stalled while the right wing, with its slats still deployed, continued to produce lift. The jetliner subsequently rolled to the left until it was partially inverted, reaching a bank angle of 112 degrees, before crashing in an open field by a trailer park near the end of the runway. The engine separation was attributed to damage to the pylon rigging structure holding the engine to the wing caused by faulty maintenance procedures at American Airlines.
While maintenance issues and not the actual design of the aircraft were ultimately found responsible for the crash, the accident and subsequent grounding of all DC-10s by the Federal Aviation Administration added to an already unfavorable reputation of the DC-10 aircraft in the eyes of the public caused by several other incidents and accidents involving the type. The investigation also revealed other DC-10s with damage caused by the same faulty maintenance procedure. The faulty procedure was banned, and the aircraft type went on to have a long passenger career. It has since found a second career as a cargo airplane.
The aircraft involved was a McDonnell Douglas DC-10-10 registered N110AA. It had been delivered on February 25, 1972, and at the time of the crash had logged just under 20,000 hours of flight over seven years. The jet was powered by three General Electric CF6-6D engines. A review of the aircraft’s flight logs and maintenance records showed that no mechanical discrepancies were noted for May 11, 1979. On the day of the accident, the records had not been removed from the aircraft, as was standard procedure, and they were destroyed in the accident.
Captain Walter Lux, 53, had been flying the DC-10 since its introduction eight years earlier. He had logged around 22,000 flying hours, of which about 3,000 were in a DC-10. He was also qualified to pilot 17 other aircraft, including the DC-6, DC-7, and Boeing 727. First Officer James Dillard, 49, and Flight Engineer Alfred Udovich, 56, were also highly experienced: 9,275 hours and 15,000 hours respectively, and between them they had 1,830 hours flying experience in the DC-10.
The weather was clear, with a northeast wind at 22 knots (41 km/h). At 2:50 CDT, Flight 191 pushed back from gate K5 and was cleared to taxi to runway 32R/14L. Maintenance crews present at the gate did not notice anything unusual during pushback, engine start, or taxi.
Everything looked normal as the flight began its takeoff roll at 3:02.
Just as the aircraft hit takeoff speed, the number one engine and its pylon assembly separated from the left wing, ripping away a 3-foot (0.91 m) section of the leading edge with it. The combined unit flipped over the top of the wing and landed on the runway. Robert Graham, supervisor of maintenance for American Airlines, stated, “As the aircraft got closer, I noticed what appeared to be vapor or smoke of some type coming from the leading edge of the wing and the No. 1 engine pylon. I noticed that the engine was bouncing up and down quite a bit and just about the time the aircraft got opposite my position and started rotation, the engine came off, went up over the top of the wing, and rolled back down onto the runway. Before going over the wing, it went forward and up just as if it had lift and was actually climbing. It didn’t strike the wing on its way down, rather the engine followed the clear path of the airflow of the wing, up and over the top of it, and then down below the tail. The aircraft continued a fairly normal climb until it started a turn to the left. And at that point, I thought they were going to come back to the airport.”
It is not known what was said in the cockpit in the 50 seconds leading up to final impact, as the cockpit voice recorder lost power when the engine detached. The only crash-related audio collected by the recorder is a thumping noise (likely the sound of the engine separating) followed by First Officer Dillard exclaiming “Damn!”, at which point the recording ends. This may also explain why Air Traffic Control was unsuccessful in their attempts to radio the crew and inform them that they had lost an engine.