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.

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.

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Farnborough airshow, a week of spectacle.

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 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.

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.

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.

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