1952 Farnborough Airshow crash

On 6 September 1952, a prototype de Havilland DH.110 jet fighter crashed during an aerial display at the Farnborough Airshow in Hampshire, England, killing 31 people. The jet disintegrated mid-air during an aerobatic manoeuvre, causing the death of pilot John Derry and onboard flight test observer Anthony Richards. Debris from the aircraft fell onto a crowd of spectators, killing 29 people and injuring 60.

The cause of the break-up was later determined to be structural failure due to a design flaw in the wing's leading edge. All DH.110s were initially grounded, but after modification to its design, the type entered service with the Royal Navy as the Sea Vixen.

Strict safety procedures were subsequently enacted for UK air shows and there were no further spectator fatalities until the 2015 Shoreham Airshow crash in which 11 people died.

Breakup
The planned demonstration of the DH.110 on that day was nearly cancelled when the aircraft at Farnborough, WG 240, an all-black night fighter prototype, became unserviceable. It was de Havilland's second DH.110 prototype, and had been taken supersonic over the show on the opening day. Derry and Richards then collected WG 236, the first DH.110 prototype, from de Havilland's factory in Hatfield, Hertfordshire, and flew it to Farnborough with just enough time to start their slot.

Following a supersonic dive and flypast from 40,000 ft and during a left bank at about 450 kn toward the air show's 120,000 spectators, the pilot pulled up into a climb. In less than a second, the aircraft disintegrated: the outer sections of the wing, both engines and the cockpit separated from the airframe. The cockpit, with the two crew members still inside, fell right in front of the spectators nearest the runway, injuring several people. The engines travelled much further on a ballistic trajectory; one engine crashed harmlessly, but the second one ploughed into the so-called Observation Hill, causing most of the fatalities. The rest of the airframe fluttered down and crashed on the opposite side of the runway.

One eyewitness was Richard Gardner, then five years old. He recalled in adulthood:

"I'll never forget, it looked like confetti, looked like silver confetti. The remaining airframe floated down right in front of us. It just came down like a leaf. And then the two engines, like two missiles, shot out of the airframe and hurtled in the direction of the airshow. There was a sort of silence, then people, one or two people screamed but mostly it was just a sort of shock. You could hear some people sort of whimpering which was quite shocking."

Sixty-three years later, speaking on the BBC Today radio programme in the wake of the Shoreham Airshow disaster, author Moyra Bremner recalled her own traumatic experience. A huge bang silenced the crowd and was followed by "My God, look out" from the commentator. Bremner, standing on the roof of her parents' car, realised that an engine was heading straight towards her. It passed a few feet over her head, a "massive shining cylinder", and then plunged into the crowd on the hill behind.

Following the accident the air display programme continued once the debris was cleared from the runway, with Neville Duke exhibiting the prototype Hawker Hunter and taking it supersonic over the show later that day.

Aftermath
Queen Elizabeth II and Duncan Sandys, the Minister of Supply, both sent messages of condolence. The coroner's jury recorded that Derry and Richards had "died accidentally in the normal course of their duty", and that "the deaths [of the spectators] were accidental", adding that "no blame is attached to Mr. John Derry".

The investigation concluded that the manoeuvring had caused an airframe instability because of a faulty D-nose leading edge arrangement (which had successfully been used in the lighter subsonic de Havilland Vampire). The redesigned DH.110 resumed flights in June 1953 and was eventually developed into the de Havilland Sea Vixen naval fighter.

More stringent airshow safety measures were subsequently introduced: jets were obliged to keep at least 230 m from crowds if flying straight and 450 m when performing manoeuvres, and always at an altitude of at least 150 m.