American Airlines Flight 191 should have been a standard flight from Chicago to Los Angeles. Instead, the name conjures horrifying visions of an aircraft in distress, a flight crew unable to recover, and the last moments of 273 lives.
The DC-10: A Troubled History
Introduced on August 5, 1971, the McDonnell Douglas DC-10 was designed as a smaller, more fuel-efficient alternative to Boeing’s 747. Though its capacity for passengers lagged behind its larger rival, the 3-engine DC-10 was also less of a guzzler than the 4-engine 747. The idea of such an intermediate, widebody aircraft was a popular one and McDonnell Douglas quickly received 55 orders—25 to American Airlines and 30 to United.
One design feature that received widespread attention was the DC-10’s cargo door. Whereas other airlines had cargo doors that opened inward, the DC-10’s cargo door opened outward. This ensured that no cargo space went to waste, an enticing proposal to potential customers. There was, however, a drawback that came with this design: the outward force of pressurization at altitude makes these types of doors susceptible to failure and explosive decompression. To counteract this force, such doors must be equipped with a heavy locking mechanism.
On June 12, 1972, the first failure in this system became apparent.
American Airlines Flight 96 was nearing the end of its route from Los Angeles To New York City. After a stop in Detroit, the plane began climbing towards its assigned altitude when its aft cargo door opened and broke off. The subsequent decompression led to a partial collapse of the cabin floor which damaged several control cables that ran beneath.
Luckily, there was no damage to the hydraulic systems, so the flight crew was able to maintain some manner of control. The aircraft was able to make an emergency landing back in Detroit and, while 11 people suffered injuries, there were no fatalities. The investigation into the accident determined that the actuator motors used to rotate the pins in the cargo door’s locking system had not completed its rotation. This was likely due to insufficient voltage to the motor. The ground crew would have heard the motor engage and run, assuming that the door was safely secured once the motor stopped.
On March 3, 1974, a Turkish Airlines DC-10 took off from Istanbul, destined for London. After a stop at Paris’ Orly International Airport, the flight departed and began climbing out. Shortly after being cleared to 23,000 feet, one of the rear cargo doors blew out, taking with it a section of the cabin floor and 6 passengers.
As in Flight 96’s case, the cabin floor collapsed; this time, however, the control cables were completely severed. The flight crew fought for control of the stricken aircraft but were unable to save it. Just over one minute after the emergency began, the DC-10 crashed into the Ermenonville Forest. All 346 occupants (335 passengers, 11 crew) were killed.
While this accident is similar to the earlier American Airlines accident, the investigation turned up one very important piece of information. A ground crew—encountering issues with closing the door—had filed down the locking pins. As a result, the door—which was designed to withstand 300 psi—failed when met with only 15 psi.
This isn’t to absolve McDonnell Douglas, only to point out a mitigating factor.
This accident led to a complete overhaul of the DC-10’s cargo door locking mechanism, a redesign that sought to prevent uncontrolled movement of the locking pins.
The accident also opened McDonnell Douglas up to several lawsuits from families of the victims while creating public scrutiny around the safety of the DC-10.
American Airlines Flight 191
On May 25, 1979, Captain Walter Lux flew into Chicago O’Hare, set to spend Memorial Day Weekend with his family. Instead, a colleague with a family emergency approaches him with a request: take over Flight 191, bound for Los Angeles. Lux accepts and heads off to prepare for the unexpected flight.
Passengers begin boarding the plane on this beautiful and clear Chicago afternoon. Being a holiday weekend, the plane begins filling up. Lux meets his flight crew: First Officer James Dillard and Flight Engineer Alfred Udovich. The trio has over 45,000 combined flight time, 1,800 of them in the DC-10. They comprise an experienced flight crew, one any passenger would feel at ease with.
At 3:04 pm, American Airlines Flight 191 began its takeoff roll on runway 32R.
Just before rotation, the pylon that held the #1 engine to the left wing failed. As the nose of the plane lifted, the engine began to detach, swinging forward and carrying over the wing’s leading edge before breaking free.
A thud is heard in the cockpit and Dillard—the pilot in control during this stage of the flight—realizes that something is wrong. The cockpit voice recorder picks up a single word from the first officer:
Following this, the recorder goes silent as it draws power from the now-detached #1 engine.