On 3 March 1974, the McDonnell Douglas DC-10 operating the flight crashed into the Ermenonville Forest, 37.76 kilometres (23.46 mi) outside Paris, killing all 335 passengers and 11 crew on board.

[1][2][3] The crash occurred when an incorrectly secured cargo door at the rear of the plane burst open and broke off, causing an explosive decompression that severed critical cables necessary to control the aircraft.

[4] The handle on DC-10 cargo doors could close despite the latches being in the wrong position, a discovery made after previous services, most notably during the incident involving American Airlines Flight 96 in 1972.

Finally, the latching had been performed by a baggage handler who did not speak Turkish or English, the only languages provided on a warning notice about the cargo door's design flaws and the methods of compensating for them.

[6] In the following investigation, it was found that a similar set of conditions, which had caused the failure of an aircraft floor following explosive decompression of the cargo hold, had occurred in ground testing in 1970 before the DC-10 series entered commercial service.

[7] The aircraft, a DC-10 Series 10 (production designation Ship 29), was built in Long Beach, California, under the manufacturer's test registration N1337U,[8] and leased to Turkish Airlines as TC-JAV on 10 December 1972.

Just after the aircraft passed over the town of Meaux, the rear left cargo door blew off and the sudden difference in air pressure between the cargo area and the pressurized passenger cabin above it, which amounted to 36 kPa (5.2 psi),[10]: 44  caused a section of the cabin floor above the open hatch to separate and be forcibly ejected through the open hatch, along with six occupied passenger seats attached to that floor section.

The aircraft almost immediately attained a 20-degree pitch down and began picking up speed, while Captain Berköz and First Officer Ulusman struggled to regain control.

Controllers also picked up a distorted transmission from the plane and the aircraft's pressurization and overspeed warnings were heard over the pilots' words in Turkish, including the co-pilot saying, "the fuselage has burst!"

[10]: 6  At the point of impact, the aircraft was traveling at a speed of approximately 423 knots (783 km/h; 487 mph) at a slight left turn, fast enough to disintegrate the plane into thousands of pieces.

The majority of the passengers were British, including members of an amateur rugby team from Bury St Edmunds, Suffolk, who were returning from a Five Nations match between France and England.

[10]: 2 The Lloyd's of London insurance syndicate that covered Douglas Aircraft retained Failure Analysis Associates (now Exponent, Inc.) to also investigate the accident.

The outward-opening design presents the risk of the hatch being blown open by the pressure inside the cargo area if the latch were to fail during flight.

The rotating movement of the torque shaft is brought about by an electric actuator, through a linkage that includes a crankshaft that ensures the "over-center" position of the whole system.

If the latches were not properly closed, the pins would strike the torque tube flanges and the handle would remain open, visually indicating a problem.

Also, there was an indicator light in the cockpit, controlled by a switch actuated by the locking pin mechanism, that remained lit until the cargo hatch was correctly latched.

[citation needed] The cargo door design flaws, and the consequences of a likely aircraft floor failure in the event of in-flight decompression on the DC-10, had been noted by Convair engineer Dan Applegate in a 1972 memo.

[citation needed] The National Transportation Safety Board's (NTSB) investigation into Flight 96 determined that baggage handlers forced the locking handle closed, and the latches did not engage fully because of an electrical problem.

In the case of Flight 96, the plane was able to make a successful emergency landing because not all of the underfloor cables were severed, thus allowing the pilots limited control.

This greatly contrasted with Flight 981, where all of the underfloor cables were severed in the decompression and the pilots completely lost control of the plane.

This meant that the pins did not extend past the torque tube flanges, allowing the handle to be closed without excessive force (estimated by investigators to be around 50 pounds-force or 220 newtons) despite the improperly engaged latches.

Although French media outlets called for Mahmoudi to be arrested, the crash investigators stated that it was unrealistic to expect an untrained, low-wage earning baggage handler, who could not read the warning notice, to be responsible for the safety of the aircraft.

The Boeing 747 has experienced several such incidents, the most noteworthy of which occurred on United Airlines Flight 811 in February 1989, when a cargo hatch failure caused a section of the fuselage to burst open, resulting in the deaths of nine passengers who were blown out of the aircraft.

[24] The NTSB's recommendations, issued following the earlier Flight 96 incident, were intended to reduce the risk of another hatch failure but were not implemented by any airline.