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April, 2003 Archive Story

The Loss of XM990

XM990 was first flown on 21/9/61 and delivered to LCS Middleton St George, being uncoded at this time. On 1/6/63, the LCS was re-titled 226 OCU and the T4 tail coded 990. Middleton St George was sold to become Teeside Airport and 226 OCU relocated to Coltishall. The following is an account of the loss of T4 XM990 as it was related to me by an RAF engineer based at Coltishall and now working for Air UK at Norwich. He was detailed to retrieve the ejection seats, PSP and canopy from the crash site. I also talked to two eye-witnesses, one of whom bid for the Binbrook Lightnings when they were sold off, the other being my brother in law.

It had been decided to perform a diamond 16 fly-past in the Battle of Britain Open Day at RAF Coltishall on 19/9/70, and Lightning T4 XM990 was included. The week prior to the open day, XM990 was undergoing checks to solve control problems which added to the already high workload the maintenance engineers were under preparing 16+ Lightnings for the flying display. After an air test and practicing the formation, XM990 was ready. Large crowds enjoyed the open day and the flying, highlighted by the diamond 16 formation. Late in the afternoon, one of the Lightnings, flown by Sqn Ldr Eric Hopkins, encountered brake problems when landing, blocking the runway. The remaining aircraft, including '990, were diverted to Wattisham.

It was early evening before Coltishall became operational again and '990 approached the airfield. Suddenly and without any warning the Lightning started corkscrewing, losing height with every revolution. Swiftly assessing the situation, the pilot applied power and pulled the aircraft up at the top of each corkscrew, gaining precious height. To people on the ground it appeared that the pilot was staging an impromptu display of his own, but inside the plane the crew of Flt Lt John Sims and Flt Lt Brian Fuller knew differently - they had lost control!

Eye-witnesses watched as something appeared to fall off the plane; it was, in fact, the canopy, followed by one of the crew ejecting. The pilot had to time his ejection on the next upward corkscrew, which by now was getting very close to the ground. As he left the aircraft it had time to complete only 1½ more turns before crashing inverted into a small wood bordering the A1140 Norwich to South Walsham road very close to the village of Little Plumstead. Part of the tail unit was hurled across the road, inches in front of a car which stopped with debris and soil covering the bonnet. There was no fuel fire, but parts of the wreckage had caught fire.

Local people hurried to assist the crew. One had parachuted into a wood. He was located in a small clearing, having removed his helmet and lifejacket, and complained of pains to the back of his neck. His parachute was hanging about ten feet up a tree. He was concerned about the other crewman and also about where the Lightning had crashed. He said he had had only seconds before the crash to eject and asked them to tell his wife he was OK. As he was speaking, the other crewman came into the clearing looking for him and upon seeing each other they both looked greatly relieved. The Coltishall SAR Whirlwind soon arrived and took them to hospital, one of them on a stretcher. The crash site was cordoned off for nearly a week while the wreckage was examined by the RAF before it was removed, along with tons of topsoil; even today you can see the depression.

The inquiry, following the crew's evidence, concentrated on the controls and control surfaces. Helped by the lack of a major fire, it was found that one of the aileron linkages had not been securely fitted and had vibrated out with the aileron movement causing loss of control. Fortunately, the crash of XM990 did not result in any loss of life or any great damage to property. I'm not 100% sure that the ranks given for Sqn Ldr Hopkins and the crew of XM990 are correct, but the rest of the facts are correct to the best of my knowledge.

My interest was stimulated by the plane crashing some two miles from where I used to live and only 600 yards from my brother-in-law's bungalow. He thought his time had come when he saw the jet heading straight for him until it veered away on its last corkscrew and hit the trees. Apart from this connection, it was only later during the Manx Grand Prix on the Isle of Man racing motorcycles that I found out that my friend Tony Martin was stationed at Coltishall and worked on the Lightnings with 226 OCU. He even declined a flight in a T4. He reckoned it was too risky, and this from a man who has finished 4th in the Manx Grand Prix on a TZ350 Yamaha!! If any members have any photos of XM990, I would like to make a model of the aircraft. Photos would be returned, etc.

Mike Baxter

More information regarding this crash

Hi,

I was reading the story published by Mike Baxter of the events during the 1970 BoB Coltishall air show and the loss of Lightning T.4 XM990.  Mikes' story is accurate but perhaps my recollection will add a little more detail and explanation as to why the aircraft was lost.  I was a Sgt Propulsion fitter on the 226 OCU Line Rectification Team at the time and worked extensively on '990 in the week before the crash.

'990 had been on a major servicing in the weeks leading up to the crash.  The work included a lot of time-expired airframe components like PFCUs being changed and extensive work on the Fire Integrity modification programme.  When the a/c was first rolled out, I did the engine runs (both engines and jet-pipes had been removed), and I recall we had a lot of trouble with one of the reheat light-ups.  When this was sorted, the a/c flew on its first post-major air-test and one of the problems reported was 'erratic' aileron response.  The riggers checked all control range of movements and all seemed normal.  Hydraulics were bled and PFCUs checked.

Another air test was flown and still the roll control response was deemed unsatisfactory.  In the hangar, leading edge panels came off and all control runs were rechecked.  All seemed OK.  However, we still had an intermittent reheat problem, so more ground runs were called up for which I was detailed to perform.  On these, the riggers re-checked control range of movements using engine-driven hydraulics rather than the hangar hydraulic test rigs (in case that was the problem).  Another air test was flown on the Friday afternoon, and this time the a/c was deemed serviceable.

We were struggling to get 16 aircraft serviceable for the big BoB flypast and formation and there was some nervousness about putting this a/c in a big 16 diamond formation over a public crowd.  So, '990 was made the reserve a/c in case another one went u/s.  Ultimately, it was flown in the formation.

One of my neighbours in Coltishall village was an instructor on 1 Sqn of the OCU (the T.4s and F.1As).  After the crash, he told me the crew reported that as '990 was en-route to Coltishall from its diversion to Wattisham, it developed a slow roll which required full opposite trim and opposite aileron to counteract, but the a/c could be held straight and level.  On preparing to join the Coltishall circuit and approach, the landing gear was selected down, and it was at this point that the roll became uncontrollable.  After several rotations, the crew ejected and mercifully were saved.  My recollection of the reasons for the roll becoming uncontrollable are that with the gear down, the aileron range of movement is deliberately reduced to avoid over-stressing the gear and the airframe.

The cause of the control malfunction (we were told) was that during the major all the aileron control runs were disconnected along the leading edge of the wings.  One spherical bearing/fork end joint in the control run had been pushed together, but no bolt fitted.  In the panic to get the a/c ready, a section of leading edge panel over this joint had been refitted without the missing bolt being spotted.  There was just enough 'grip' by the fork-end on the spherical bearing to carry the linear push-pull input load to the PFCU, but (probably) some movement also, hence the erratic roll response in flight on the first two air tests.  Eventually, en-route from Wattisham, the joint parted.  This caused the aileron on that side to 'freeze' and the slow roll to develop.  At this point the a/c had full range of movement on one aileron only.  When the gear was lowered, that was reduced to about 50%, making control impossible.

This was a huge source of embarrassment to the Engineering community on the OCU, but we were all very relieved that neither the crew nor any members of the public were injured or worse.  As Mikes' story revealed, it was a close thing.

Best regards

Don Arnott

107 Colwell Drive

Witney

OX28 5NW

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