The 1973 Paris Air Show Tu-144 crash of Sunday 3 June 1973 destroyed the second production model of the Russian supersonic Tupolev Tu-144. The aircraft disintegrated in the air while performing extreme manoeuvres and fell on the town of Goussainville, Val-d'Oise, France, killing all six crew members and eight people on the ground. The crash ended the development program of the Tupolev Tu-144. The official inquest did not conclusively determine the cause of the accident and several theories have been proposed.

The aircraft involved was Tupolev Tu-144S СССР-77102, manufacturer's serial number 01–2, the second production Tu-144. It was first flown on 29 March 1972. This aircraft had been modified compared to the initial prototype to include landing gear that retracted into the nacelles and retractable canards. The pilot was Soviet test pilot Mikhail Vasilyevich Kozlov and the co-pilot was Valery M. Molchanov. Also on board were flight navigator G. N. Bazhenov; V. N. Benderov, deputy chief designer and engineer major-general; B. A. Pervukhin, senior engineer; and A. I. Dralin, flight engineer. The crash occurred in front of 250,000 spectators near the end of the Paris Air Show at Le Bourget airport, the world's largest air show and aerospace industry exhibition event.

During the show there had been "fierce competition between the Anglo-French Concorde and the Soviet Tu-144". The Soviet pilot, Mikhail Kozlov, had bragged that he would outperform the Concorde. "Just wait until you see us fly," he was quoted as saying. "Then you'll see something." On the final day of the show, the Concorde, which was not yet in production, performed its demonstration flight first. Its performance was later described as unexciting, and it has been suggested that Kozlov was determined to show how much better the Russian aircraft was.

After several minutes in the air performing aerobatic manoeuvres in its second demonstration flight of the show, the Tu-144 flew a high-speed pass above the runway with the landing gear out and the "moustache" canards extended then, with all four engines at full power, it went into a steep and rapid climb. Below 2,000 ft (600 m) the aircraft stalled and fell into a steep dive. As the pilot tried to pull out of the dive at 400ft with the engines at full power, "the entire left wing outboard of the left-hand engines broke away. The aircraft snap-rolled left and inverted, overload stresses fractured the fuselage forward of the wing, and fuel vapour ignited." The aircraft broke apart in mid-air and crashed in flames on the town of Goussainville, eight kilometres north of Le Bourget, destroying 15 houses and killing all six people on board the Tu-144 and eight more on the ground. Three children were among those killed and 60 people received severe injuries.

The crew of the Tu-144 were buried at the Novodevichy Cemetery in Moscow on 12 June 1973.

Following the crash, Marcel Dassault called for the 1975 Paris Air Show to be held at Istres, which is situated in open country 40 km (25 mi) northwest of Marseille.

The crash eroded enthusiasm surrounding the Tu-144, which was already in decline. Although not a major factor within the Soviet Union, environmental concerns about the supersonic transport (SST) concept were increasing in the West. Earlier in the year, government agencies in the U.S. and U.K. had issued forecasts that SST per-seat operating costs would substantially exceed those of conventional airliners for the foreseeable future, and a U.K. government report said the Tu-144 would have even higher per-seat operating costs than Concorde. Historian Howard Moon speculates that these factors—together with continuing technical problems, an overextended Tupolev design bureau, high development costs coupled with a scarcity of alternate applications for Tu-144 technologies, and high fuel prices in the West stemming from the 1973 oil crisis a few months later—prompted Soviet leaders to deprioritize the aircraft's service entry with Aeroflot, as its value as a prestigious symbol of Soviet technical prowess had diminished.

By 1975, the Soviet aviation industry had pivoted to promotion of new conventional subsonic airliners, the Yakovlev Yak-42 and Ilyushin Il-86. Restrictions on the Tu-144 following the Paris Air Show crash meant that it only saw limited service during 1977 and 1978, and it was finally withdrawn following another crash in May 1978. The Tu-144's rival, the Concorde, went on to serve with British Airways and Air France for 30 years afterwards, being finally withdrawn from service in 2003 due to low passenger numbers following the crash of Flight 4590 (coincidentally also within the vicinity of Le Bourget), rising service costs and the slump in the aviation industry following the September 11 attacks.

The accident was investigated by the DTCE, part of the French military, which was responsible for accidents involving prototype aircraft in France. The wreckage was recovered to a hangar at Le Bourget, with some of it being flown by an Antonov An-22 to the Soviet Union. Moon writes that the investigation was clouded by political considerations from the outset; the Soviets were distrustful of the French proposal to reconstruct the wreckage in the hangar, being unfamiliar with the technique, and the French had been actively seeking Concorde overflight rights in the Soviet Union. An exoneration of the Tu-144 from a technical and design standpoint was in the political interests of both countries. Throughout the investigation, the Soviets strenuously objected behind the scenes against French attempts to issue firm conclusions. The official report from the French investigative commission, produced in collaboration with Soviet experts, proposed a hypothesis involving a French jet plane in proximity and an unsecured Tu-144 crew member with a film camera, which might have inadvertently blocked the controls during an evasion manoeuvre. However, due to a lack of concrete evidence supporting this theory, the commission concluded that the exact cause of the disaster remains undetermined. At the same time, the report specifically stated that there was "no abnormality in either the airliner's design or the general functioning of the aircraft and its systems", and it ruled out inadequate structural design as a cause. While the investigation's outcome was largely suitable for both sides, it gave rise to a number of alternative theories.

One Soviet-promoted theory is that the Tu-144 maneuvered to avoid a French Mirage chase plane that was attempting to photograph its unique canards, which were advanced for the time, and that the French and Soviet governments colluded with each other to cover up break-up of the plane during a pull-up maneuver. The flight of the Mirage was denied in the original French report of the incident, perhaps because it was engaged in industrial espionage. More recent reports have admitted the existence of the Mirage (and the fact that the Soviet crew were not told about the Mirage's flight), although not its role in the crash. However, the official press release did state: "though the inquiry established that there was no real risk of collision between the two aircraft, the Soviet pilot was likely to have been surprised".

Moon stresses that last-minute changes to the flight schedule, combined with "sloppy" air traffic control, would have disoriented the pilots in a cockpit with notably poor sightlines; Moon notes that the flight crew had prepared a choreographed flight demonstration routine that had been practiced at least six times before leaving the Soviet Union, but it had to be discarded because of the scheduling changes. He also cites an eyewitness who claims the co-pilot had agreed to take a camera with him, which he may have been operating at the time of the evasive maneuver. The initial approach may have been an attempted landing on the wrong runway, which occurred due to a last-minute shortening of the Tu-144's display.

An important contributing factor could be that control surfaces deflection had been de-restricted before the flight, perhaps to allow a more impressive demonstration, giving way for a bug of the electronics flight controls which deflected the elevons 10 degrees down after the retraction of the canards, causing the sudden dive.

On 24 October 1973, the London Daily Telegraph published a report stating that a wrench fell into the recess around the control stick, jamming the aircraft flight control system.

A self-styled group calling itself "Liberation of Rudolf Hess" claimed to have blown up the Tu-144 in protest of Hess's continued imprisonment at Spandau Prison; however, Hess's son rejected this claim, saying that he had never heard of the group.

Bob Hoover, a pilot on the supersonic Bell X-1 program, believed that the rivalry of the Tu-144 and Concorde had led the pilot of the Tu-144 to attempt a manoeuvre that went beyond the abilities of the aircraft: "That day, the Concorde went first, and after the pilot performed a high-speed flyby, he pulled up steeply and climbed to approximately 10,000 [feet] before leveling off. When the Tu-144 pilot performed the same manoeuvre he pulled the nose up so steeply I didn't believe he could possibly recover."

• Moon, Howard (1989). Soviet SST: the technopolitics of the Tupolev Tu-144. New York City: Orion Books. ISBN 0-517-56601-X.

• Accident description on the Aviation Safety Network