Introduction

Introduction. It is Saturday the 6th of September 1952 and test pilot John Douglas Derry DFC prepares his prototype supersonic aircraft to show off over the skies of Farnborough for a waiting and excited crowd. The pilot is highly experienced, cutting his teeth in the skies during ww2. He is the first Briton to exceed the speed of sound, and this new plane is in safe hands. Derry and his onboard flight test observer Anthony Richards set off to reach the airshow for 3:45. The 2 seater prototype, roars over the baying crowd, it flies past the 120,000 large audience, in a dramatic display of precision piloting skills the plane pulls up. Suddenly something seems wrong the plane has disappeared from view. The aircraft disintegrates under the extreme forces of the display showering bystanders with debris and one of the two engines plows into the crowd.... It would go down in history as one of Britain’s worst air show disasters, and would cast doubt over a fledgling national pride event. Wait until the end for my ratings. Let’s get started. My name is John and this is a brief history of the 1952 Farnborough airshow crash.

Background

A little Background for a big crash Our story starts with the closing months of the Second World War. Both the axis and allied powers are locked in an arms race that have catapulted aviation development from planes impersonating the First World War like this to war birds with unbelievable amounts of horse power. The need for ever faster aircraft would start to render the traditional piston engine driven plane redundant, at least in the fighter role. The uk in the closing stages of ww2 was the only member of the allies to field a jet fighter with the gloster meteor. The second jet fighter fielded was manufactured by De Havilland called the vampire, it first saw service in 1946 and became a staple in the RAF fleet. What was interesting and unique with the Vampire was it’s dual tail configuration, so much so were dehavilland enamored with this design that for their next project the twin boom tail concept would to be developed upon. Starting in 1946 dehaviland entered into talks with the British admiralty to develop a new alweather radar equipped super sonic fighter. Because of these specifications the design would require a 2 person crew, one to operate navigation and radar equipment as well as a pilot , 2 engines for redundancy were also specced due to working over large bodies of water. And A reliability short take off and landing distance for working in aircraft carriers, which would require decent flaps, and to deal with the high speeds preferable a swept wing arrangement. The new plane which would gain the internal designation DH110, would borrow the twin boom tail from the vampire. The raf seemed to show a promising interest in the 110 and ordered 9 prototypes. But a worried admiralty cut off its interest in the 110 instead preferring a more readily available Dehaviland sea vixen for its replacement of its piston driven fleet. The RAF would also pull back its order from 9 to just 2 prototypes. In 1949. But Dehaviland who were very experienced in working with the UK government decided to carry on with the project in the hopes that minds can be changed later on and orders would materialise. On 26 September 1951, the first prototype airframe took to the skies at Hatfield Aerodrome. The new aircraft exceeded expectations, originally Only thought to be able to hit supersonic speeds in a slight dive, the design actually allowed this to be achieved in level flight. A second and improved prototype would also be built to show off the dh110 in night fighter form being given the identification number wg240, with the first given the number wg236. /////// Farnborough airshow, a week of spectacle.

Farnborough Airshow

The Farnborough airshow was devised as a way to boost trade for the British aerospace and defence industries, through the means of spectacular aeronautical displays and static exhibitions. Post war Britain represented the cutting edge in technology and after its commencement in 1948 some truly impressive designs were shown off in the hopes of generating foreign orders. The show would consist of Monday to Friday open for trade only displays and exhibitions followed by the weekend for the public. As a side note I used to love going farmborough, my dad used to work for BAE and we got trade day tickets, I saw the euro fighter there. In its first year the futuristic Armstrong Whitworth A.W.52 flying wing was revealed to the public. 1949 saw the unveiling of the achingly beautiful but tragically flawed Dehaviland comet. 1950 saw the insane Bristol brabazon, 1951 saw Canberra demonstrations as well as sea veonoms in flight. And that leads us onto 1952. The 1952 airshow looked to be an exciting display of some New designs to both trade and public visitors alike. The show on the first day wowed the spectators with a supersonic pass from the second DH110 prototype Wg340. Other aircraft on display was the bickers Vulcan the giant swept wing atomic bomber, During the week of business stirring and areal acrobatics all seemed good. The cutting edge of British aviation was shown off and no doubt many a foreign government official wanted to get their hands on some of the hardware on display.

The Disaster

The disaster. The 6th day got off without a hitch, instead of just trade spectators today the fields surrounding farnborough airport are filled with the public. Some 120,000 people are watching the skies.. in the afternoon the new prototype Dh110 is set to exhibit supersonic flight for the audience. But as pilot John Derry and onboard flight test observer Anthony Richards make their way to collect the jet black fighter a spanner is thrown in the works. The aircraft set to wow the spectators is out of action, the two are faced with a decision, cancel their display or... You see there was an alternative wg236 but it was parked up at Dehavilands factory rather than at Farnborough, the first prototype, instead of it being black she was a bright silver. The pilot and his crew mate climb aboard a Dehaviland dove to make their way to where wg236 was being stored. The two agreed to take this out instead, the plan was to be an identical display from the first day, after all it was Derry who was also at the controls. So in theory there should be no difference same plane same show. Wg236 takes off from de Havilland's factory in Hatfield, Hertfordshire. The plane flew across to farnborough for a 15:45 display. The the sky is blue If but scattered with clouds, the conditions allow the spectators to follow the dh110 as it approaches the display. Derry approaches from west at high altitude, roughly 40,000 feet 12,000m. He enters his plane into a high speed dive, reaching Mach 1 for the audience to experience a sonic boom. The dh110 flies along the runway from the west at high speed. The aircraft then turns left to port at a speed of around 450kts or 520mph (830kph) almost as soon as he banks Derry then pulls into a steep climb. The aircraft under the immense force loading began to separate. the outer sections of the wing, both engines and the cockpit were flung from the airframe. The crew compartment fell into the ground near the runway right in front of the spectators, injuring a few from the impact. One eye witness would say it was like silver confetti, the remaining parts of the aircraft would be far more deadly. The announcer over the tannoy system called out rather ominously to watch out for the engines. One of the two avro engines flew over the heads of the crowd and crashed into the roof of the hanger but the other one hurtled into the densely packed observation hill. It would be here that the most amount of casualties would be inflicted. Once the dust settled the crowd ran to help the injured, over the tannoy the announcer immediately started asking for any photos or cinefilm, to be given to the RAE for any pending investigation.

Investigation

The investigation. The 2 aircraft crew, and 29 civilians in the crowd, were killed as well as 60 injured. Needless to say the cause had to be found, was it pilot error, the new plane or both. It looked unlikely to be the fault of Derry as many of his contemporaries at the time stated that he was a conscientious pilot. His career was as for a 30 year old full of experience from 1944 during ww2 gaining a Distinguished flying cross. After the war he then joins Dehaviland as a test pilot, it seemed like operator error was unlikely as his display was pretty much the same just a few days before. This refocused investigators back onto the plane itself, and moreover the difference between wg240 wg236. Well the point of prototypes is to test out different aspects of a design and due to this the two planes had a simple but glaring difference. WG 236 and WG 240 when originally built had a large boundary-layer fence on each outer wing; this metal added to the stiffness of the wing. However as part of the dh110s development and in an effort to Improve low speed performance on wg236 the metal fence was replaced with wooden ones. The weaker wood contributed to a wing of only 65% the strength of its metal fenced counterpart. The manoeuvre Derry was attempting was a Rolling Pull-up, this put a twisting force on the outer wings. As he moved the stick to the right and back to level the wings and pull the nose of the aircraft up, a downward load on the rear of the outer portion of the starboard wing was created whilst raising the nose would have generated an upward load on the whole wing. The weakened wing was unable to cope with the forces and tragically the outer part of the starboard wing was ripped off. This in turn put greater force on the other wing, this caused a sudden pitch up putting an estimated force of 30g on the crew compartment.

Aftermath

The aftermath Surprisingly the accident wasn’t the end of the dh110, although it was grounded a new modified version would take to the skies in 1954. The dh110 would eventually be developed into a navalised version called the sea vixen, although it’s supersonic abilities were removed instead only having a top speed of 0.95mach. The sea vixen would serve the Royal Navy untill 1972 when it was retired and replaced by the f4 phantom. Interestingly the phantom was procured after the failure of the TSR2, which although not a disaster I kind of want to make a video on that dumpster fire development story. Airshows in the uk were completely revamped to improve safety with crowd controls and minimum distances that air manoeuvres can be undertaken. And these rules would seem to work pretty well for 63 or so years until the shoreham air crash of 2015.

Ratings

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