On 27 March 1977, at 17:06 local time, two Boeing 747s collided on the single runway of Los Rodeos Airport on the Spanish island of Tenerife, killing 583 people. It remains the deadliest accident in aviation history. A KLM 747, registration PH-BUF, began its takeoff roll in dense, drifting cloud while a Pan American 747, registration N736PA, was still taxiing on the same runway toward an exit it had not yet reached. The KLM aircraft, already accelerating, lifted its nose and tore through the Pan Am’s upper fuselage. All 248 people aboard the KLM died; 335 of the 396 aboard the Pan Am died. The 61 survivors, all from the Pan Am’s forward section, escaped before fire consumed both aircraft.
Neither aircraft was scheduled to be at Los Rodeos. Both had been diverted there earlier that Sunday after a bomb planted by a Canary Islands separatist group exploded in the passenger terminal at their intended destination, Gran Canaria, and a second device was reported. The diversions packed Los Rodeos — a small airport with one runway, one parallel taxiway, and no ground radar — beyond its comfortable capacity. Parked airliners blocked part of the taxiway, so departing aircraft had to taxi down the active runway itself and turn around at the far end, a procedure called backtaxiing. When Gran Canaria reopened, the controllers worked to launch the backlog into deteriorating weather, with low cloud rolling across the field and visibility collapsing from a kilometre to a few hundred metres and back within minutes.
The investigation was conducted by the Spanish Subsecretaría de Aviación Civil, with formal participation by Dutch authorities (the Netherlands Aviation Safety Board), the United States, and the operators, in accordance with the international convention governing aircraft-accident inquiry. The Spanish report, released in October 1978, placed the fundamental cause squarely on the KLM captain: he began his takeoff roll without an air traffic control clearance, did not heed the tower’s instruction to stand by, and did not stop when the Pan Am crew transmitted that they were still on the runway. The Dutch authorities, while accepting that the KLM captain had taken off prematurely, emphasised a mutual misunderstanding in the radio communications and the inherent limitations of voice radio rather than assigning blame to one man alone. KLM ultimately admitted that its crew was responsible and compensated the victims’ families.
No crime was prosecuted; both captains died in the collision and the inquiry was administrative, not criminal. What the disaster produced instead was a wholesale change in how flight crews communicate and how they work together. The accident is the founding case for two enduring reforms: standardised, unambiguous radio phraseology — the word “takeoff” reserved for an actual clearance — and Crew Resource Management, the training discipline that empowers junior crew members to challenge a captain’s error before it kills everyone aboard.
On 25 May 1979, American Airlines Flight 191, a McDonnell Douglas DC-10-10 registered N110AA, crashed seconds after takeoff from Chicago O’Hare International Airport, killing all 271 people aboard and two more on the ground, for a total of 273. It remains the deadliest aviation accident on United States soil. As the aircraft rotated for takeoff on a routine service to Los Angeles, the No. 1 engine — the left wing engine — together with its supporting pylon broke away from the wing, flipped up and back over the wing’s leading edge, and fell to the runway. The aircraft, already committed to flight, climbed briefly, then rolled steeply to the left, descended, and struck the ground in an open field near a trailer park about a kilometre beyond the runway, where it disintegrated and burned. The whole sequence, from the engine departing the wing to impact, lasted only about 31 seconds.
The engine separation alone would not necessarily have been fatal — the DC-10 was designed to fly on two engines. What made the loss unrecoverable was a cascade of secondary failures caused by the engine and pylon tearing away. As the pylon ripped from the wing it severed hydraulic and electrical lines in the leading edge. This caused the outboard leading-edge slats on the left wing to retract, while those on the right wing stayed extended. The wing with retracted slats stalled at a higher speed than the other; with one wing flying and one stalled, the aircraft rolled uncontrollably to the left. The same damage disabled the cockpit instruments that would have warned the crew of the slat asymmetry and the impending stall, so the pilots, who could not see their own wings from the cockpit, flew the aircraft by the book for an engine-out climb — exactly the procedure that, with the left slats retracted, drove the dying wing into a deeper stall.
The National Transportation Safety Board investigated. Its report, AAR-79-17, determined that the engine and pylon had separated because of damage inflicted weeks earlier during maintenance. American Airlines, like some other carriers, had adopted a time-saving procedure to remove and reinstall the engine and pylon as a single unit using a forklift, rather than detaching the engine from the pylon first. The procedure was difficult to perform precisely; on N110AA a misalignment during reinstallation had cracked the pylon’s aft attachment fitting, and that crack grew under flight loads until the pylon failed on takeoff. The Board’s verdict was a maintenance-induced structural failure compounded by design vulnerabilities and oversight gaps. The accident grounded the entire DC-10 fleet for weeks and reshaped how engine maintenance procedures are approved and policed.
On 3 March 1974, Turkish Airlines Flight 981, a McDonnell Douglas DC-10-10 registered TC-JAV, crashed into the Ermenonville Forest about 40 kilometres northeast of Paris, killing all 346 people aboard — 335 passengers and 11 crew. There were no survivors. For just over three years, until the Tenerife runway collision of March 1977, it was the deadliest accident in aviation history; it remains the deadliest single-aircraft crash with no survivors, the deadliest DC-10 accident, and the deadliest air disaster on French soil.
The aircraft had left Istanbul Yeşilköy on a scheduled service to London Heathrow with an intermediate stop at Paris Orly. At Orly some 50 passengers disembarked and roughly 216 boarded, many of them travellers rebooked from carriers grounded by a British European Airways strike, including a group of English rugby supporters returning from a France–England match at the Parc des Princes. The DC-10 departed Orly heavily loaded. Roughly nine minutes after takeoff, as it climbed through about 11,500 feet over the town of Meaux, the aft left cargo door tore away from the fuselage. The pressure differential between the cabin and the suddenly depressurised cargo hold — about 5.2 pounds per square inch — collapsed a section of the passenger floor above the door. Six occupied passenger seats and the floor beneath them were ejected through the open hatch. The collapsing floor severed the control cables and hydraulic lines that ran beneath it to the tail and the centre engine. The crew lost most pitch control and rudder authority. Seventy-seven seconds after the door failed, the aircraft struck the forest at high speed in a shallow dive.
The French Minister of Transport appointed a commission of inquiry by decree the following day; because the aircraft was American-built, the commission included United States participation. Its conclusion was a matter of design. The aft cargo door used an outward-opening, latch-over-the-pressure-vessel scheme whose locking mechanism could give the appearance of being secured when the latches were not fully driven home. The door could be — and on TC-JAV had been — closed in an unsafe state. The same fundamental flaw had already failed once in flight, over Windsor, Ontario, in 1972, without a catastrophic outcome; the warning had been documented inside the manufacturer in the 1969–1972 period, most famously in an internal memorandum by McDonnell Douglas engineer Dan Applegate. The fix that should have prevented Flight 981 had been ordered, recorded as completed, and not actually installed on this airframe.
No criminal conviction followed the crash, but the litigation that did — a mass civil action settled in 1975 — pried open the manufacturer’s records and forced the design history into public view. The disaster reshaped how regulators treat a known latent flaw: the door was redesigned across the DC-10 fleet by mandatory airworthiness directive, and the episode became a standing case study in the difference between issuing a recommendation and compelling a fix.