Trials and Errors

by Mike Brooke

  I called the ship to tell them that we had them in sight and flew past their starboard side. I think that they were very surprised to see us! But we went on to make attack runs from various angles as they ploughed their way through the mountainous seas. Despite all the bucketing around the guys in the back were on the ball and I think that Mr Pope was quite pleased with what he was seeing.

  Later another rendezvous was arranged with a ‘Grey Funnel Line’ vessel in Arctic waters off the Norwegian coast. As it was now May the Met folks had said that we would have to go north of the Arctic Circle to get rough enough seas. We arranged a short detachment to the Royal Norwegian Air Force Base at Bodø and set off on Tuesday 20 May. During the transit the Norwegian radar controller told us that a Russian Tupolev 95 ‘Bear’ was headed our way at about our altitude. I asked the controller to give us an intercept heading, promising not to get too close to it. He did so and a few minutes later there was the huge four-engined bomber in all its stately splendour heading south-west, 1,000ft above us, laying thick condensation trails to mark its progress. It was truly a stirring sight. My suggestion that we gave it a squirt of our missile radar fell on deaf ears! As it turned out the weather was beautiful for the next three days, the ship was late and the seas too calm, so we did very little of any use, except a lot of sightseeing around Bodø, including a visit to a very impressive maelstrom (that’s Norwegian for a lot of fast, very turbulent water flowing through a small gap!).

  Sometimes it was amazing the type of work that came our way. Once I was asked to provide a target for a weapon trial at Larkhill Range, in Wiltshire. The target aircraft was required to fly across Salisbury Plain at 100ft and 300kt, following the contours of the ground. This was one of the few times when I pulled rank. If I was going to get this authorised by my lords and masters I was going to fly it! I prepared by first flying the required tracks across the Plain in the Wessex at a sedate 90kt to make sure there were no hidden obstructions. There weren’t and, although demanding a lot of attention, the actual trial flight went well and I received a very nice thank-you letter from the trials manager.

  After another Canberra test flight, this time assessing something called Infrared Linescan, which was day and night airborne reconnaissance equipment, I ended up being interviewed by the RAF’s Special Investigation Branch (SIB). They were the folk who, inter alia, investigated low flying complaints by the public; especially any that had escalated up to Parliamentary level. On the day in question the trial protocol had required us to try to capture images of moving vehicles when we were flying at various speeds and heights. The way that the Linescan kit worked meant that it could be limited to a maximum speed/minimum height combination, known as the V/H ratio, and work was ongoing to maximise this value.

  To give ourselves a consistent ground image that included moving vehicles we used a stretch of the M1 motorway between the Watford Gap services and Junction 16, north-west of Northampton. As the Linescan looked through an arc of about 60° each side of the vertical we could avoid flying directly overhead the motorway by flying about 100 yards to one side. The final run was done at a high V/H factor: 360kt and 250ft. Post-flight analysis would prove whether this was a limiting case. At the end of the final, southerly run, just before Junction 16, I turned left and started to climb for our return at 2,000ft to Bedford, just a few minutes away.

  The trial was a success but three days later I had the aforementioned SIB visitor. This followed an earlier telephone call when I had told the investigating officer that I was indeed flying the aircraft reported as being ‘dangerously low’ near the M1 on the afternoon of the day in question. Since that call I had asked the boffins to give me a copy of the altitude readout for each run at 250ft. So when my interrogator asked what height I was flying at I told him that the lowest height had been 250ft above ground level.

  ‘Yes, I know that was the lowest height you were authorised to fly at but the statement from the complainant estimates that you were at 100ft or even less,’ said the SIB man. ‘Here’s a copy of the letter he wrote to his MP.’

  Now was the time to produce my evidence. ‘Here’s a readout of the altitude on the lowest of our runs. As you can see there are occasional records of just less than 250ft but the lowest of those is 245ft, so I’m afraid that the visual impression that the complainant got was an error.’

  ‘Well, I can’t argue with that, sir,’ was the very agreeable response. With that he went on his way to wherever the SIB have their home.

  The most exciting of our Canberras to fly was a modified PR9, tail number XH 132; officially it was called the SC9. I believe the letters stood for ‘Short’s Conversion’ because the large and rather unbecoming nose job, and other internal changes for the aircraft’s trials role, had been carried out by Short Brothers Aviation in Belfast.

  Because of its peculiarities only three of us flew the SC9: Dave Watson, Chris White and myself. Essentially the machine was a PR9, which had 50 per cent more thrust available than the other RRS Canberras, hydraulically powered flying controls, an autopilot and lots of fuel. But it also had a Ferranti Air Intercept (AI) 23 radar in the nose, which was operated by the pilot. In addition to all this, the normal Canberra tip-tanks had been modified to carry other sensors. As neither Chris White nor I had previously operated the AI 23 radar I arranged for us to go to RAF Binbrook, home of the AI 23 equipped Lightning fighter, to learn how to use it. After a couple of sessions in the Lightning simulator and some classroom instruction, we both felt able to use the radar to intercept the targets we would be using in the forthcoming trials. These were related to the on-going UK development of the US Sparrow air-to-air missile, known in the UK as the Skyflash. BAe were the prime contractor, but we were working with Marconi Space and Defence Systems who were developing a completely new seeker for the missile. This was semi-active, so it homed onto the radar reflection of the target illuminated by the fighter’s radar. As Skyflash was being developed for the ADV Tornado then it worked in the frequency band of the AI 24 Foxhunter. As the SC9’s AI 23 did not operate in that frequency band it directed a transmitter of the correct frequency housed in the port wingtip pod onto the target. The Skyflash seeker was housed in the starboard wingtip pod so that the FTO, in the front seat of the SC9, could assess and record what it was ‘seeing’ and how it was performing. Between us we flew sufficient trials sorties to give the Marconi folk enough to work on. Using the AI 23 was very interesting, especially in some of the more advanced interceptions, at low level or with manoeuvring targets.

  One day the ATC Briefing in the morning had included a plea for anyone airborne with some time to spare to ‘call in’ at RAF Cottesmore. The reason was that the base was gearing-up to receive its new aeroplanes and become the Tri-National Tornado Training Establishment. The air traffic controllers there were trying to get up to speed and qualified. That day I flew the SC9 out over the North Sea to work with two targets but the second one did not turn up, so we could go home early. I then remembered the plea from Cottesmore and asked if they would like us to go there to do some approaches. They were delighted to accept our offer and we spent over half an hour doing a couple of instrument, radar-guided, approaches followed by a few visual circuits. When I felt that the fuel had reached the level where it would be prudent to return to Bedford I told the local controller that the next circuit would be the last and we would like to depart to Bedford.

  ‘Roger, Blackbox Bravo, request your heading and height en-route,’ he enquired.

  ‘Blackbox Bravo requests heading 170 and Flight Level 155,’ I replied.

  ‘Roger, I’ll pass that on.’

  I then flew downwind for a touch-and-go landing. I chose not to use the flaps so that I could lift off and climb quite rapidly. I knew I would have to increase the power in stages because I was not allowed to use 100 per cent until we had achieved 190kt. When I made my downwind call, opposite the upwind end of the 9,000ft long, south-westerly runway, I told the controller that I would like clearance to clim
b to my cruising height immediately after lift-off.

  ‘Roger, Bravo, that will be OK.’

  I touched down and then applied 90 per cent power, lifted off, accelerated to 190kt, pulling the nose up and applying full power as I did so. The climb angle was very impressive and I changed frequency to the radar controller. As we passed 5,000ft I turned left, heading towards base. As I did so I noticed that we were still over the airfield. Homesick angels weren’t in it; this was amazing! I rolled out on heading 170° and almost immediately had to start to level off at 15,500ft.

  ‘Blackbox Bravo is steady and level,’ I announced, perhaps a bit smugly. I noticed that the TACAN navigation system was showing that we were less than 5 miles from Cottesmore.

  The controller indicated his surprise at the aircraft’s performance. ‘Yes, not bad for an old girl, eh?’ I replied. ‘Can your new jets do that?’ Silence.

  As well as flying all the Canberras I had arrived already qualified on the Hunter – so that was also within my remit. Dave Watson shared the flying of this particular type with me. Like all RRS aircraft this was a very special aeroplane. Being one of only three produced this mark of Hunter wasn’t unique, but it was a very different version of the original two-seat, dual-controlled Hunter T7. It was designated T (for trainer) 8 (indicating a naval version with an arrestor hook) M (this letter simply indicated that it was fitted with the Ferranti Blue Vixen radar that was destined to equip the Sea Harrier for the FAA). Of the three built ours, XL 603, was the last. The nose had been fitted with a Sea Harrier profile radome and the appropriate electronics stashed neatly inside. As the Foxhunter had for our Buccaneer, the Blue Vixen made the profile of the already good-looking Hunter even sleeker; it also had the grey and white naval paint job. The cockpit had been modified to incorporate the radar screen and the opportunity had been taken by the manufacturer to update the instrument panels and centralise the Hunter’s previously scattered and haphazard warning system.

  Although it looked modern and svelte the T8M flew just like any other two-seat Hunter! The Blue Vixen trials were well advanced when I took over the unit and subsequent progress was steady. Some very good results were being achieved for such a small radar and its ability to operate under jamming conditions was steadily improving. To aid that, the transmitter was what is known as ‘frequency agile’ so allowing the signal to get around some of the less sophisticated ECM. This trial provided a contrast to the Foxhunter in its thoroughly good management and the overall high experience levels of the Ferranti team.

  In order for me to ensure that all our pilots remained well practised (what the RAF calls ‘current on type’) some periodic training was necessary. Understandably, the trials management folk did not want lots of precious flying hours on their research machines absorbed with pilot continuation training sorties; they also wanted us to keep the risk levels as low as possible. So we had to manage our training requirements another way. The RAF had simulators for the Nimrod and the Buccaneer, which we used on a mandatory six-month cycle, but for the rest we had to use trainers. For the Canberra that was T4 WJ 992 and for the Buccaneer and Hunter we had to share a common resource with Farnborough and Aero Flight; that was Hunter T8 XF 321. The boss of Aero Flight and I had been pushing for some time to get a two-seat Hunter established at Bedford for our sole use. Eventually this was agreed. However, not long after it had finally arrived it was detached to Farnborough where someone there landed it with its wheels still up and it was written off. No names – no pack drill! Back to square one.

  The RAE’s Air Fleet Management organisation, often much maligned, came up with a wizard wheeze. The RAF was replacing its Folland Gnat trainers with the BAe Hawk and there was one, XP 513, which still had over 400 flying hours to go before its next major servicing. Effectively that would give us at Bedford at least a couple of years grace for ‘fast-jet’ training. Being a disposal the deal was essentially a free one and, as Aero Flight already operated a Gnat for esoteric aerodynamic research, the servicing requirements were already well known. However, the Aero Flight Gnat had only one seat because all the scientific equipment filled up the rear cockpit, and it was a valuable research tool.

  The ‘new’ Gnat arrived in late October and I first flew it with my old ETPS course mate George Ellis sitting bravely in the back, dispensing eloquent words of wisdom. We flew together twice while I learnt all about the tiny jet and its foibles. When George was satisfied that I was not going to get into trouble I was sent off ‘solo’. That was on Wednesday 7 November 1979. There was a special irony in this first solo on type for me. In May 1963 I had been posted to the first ever Gnat course at RAF Valley. However, delays to the aircraft’s introduction to service had changed all that and I flew the Vampire T1128 instead. It was only after this first solo Gnat flight that I realised that far from being one of the first to fly the Gnat I was probably the very last RAF pilot to convert to it! After all, it wasn’t even in service any more! It was a great little jet and, as long as you were fully aware of the possible complications of a hydraulic or engine failure it was enormous fun to fly and certainly kept me ‘sharp’. I never flew it alone. Whenever I told my guys that I was going to fly the Gnat there was a chorus of cries, ‘Got room for a small one, Boss?’ or ‘Isn’t it my turn now?’ When I left Bedford the little red-and-white jet was still there.

  Being a test pilot also got me some interesting flights with my compatriots from the more refined climes of Aero Flight. I flew quite a lot of sorties in a simulator that aimed at giving airlines an economical way to land safely in very poor visibility using contemporary airport ILSs. The prime tool for achieving these landings was a small HUD in which a flight path demand symbol was generated by a computer that received signals from a variety of sources, including a radar altimeter. All the pilot had to do was to follow the demand using the flying controls and, even without seeing the ground, safe and reasonably smooth touchdowns could be achieved. The laws that drove the demand symbol could be varied and it was our job, as test pilots, to feedback what we thought. Much use was made of the good old Cooper–Harper rating scale. It was good to be doing real test pilot things again. The system was installed in the flight’s Avro 748 twin-turboprop airliner – but, sadly, I didn’t get to fly that. The Aero Flight guys used to go off to the foggiest airports they could find and shoot approaches when no one else could get in! It struck me as odd that Amsterdam Airport Schiphol was a frequent overnight destination – was it really always that foggy in Holland?!

  I also got to fly and assess the first colour cockpit displays in the flight’s BAC-111, a very interesting flat panel LCD display in their Wessex helicopter and I made various types of approaches using a system called MADGE (Microwave Aircraft Digital Guidance Equipment) – nothing to do with the singer Madonna!

  Aero Flight had the use of a two-seater Harrier. It was used for many things over the years but when I was at Bedford it was used to quantify the optimum angle for the then still experimental ‘Ski Jump’ to be built onto the front of the RN’s new ‘Harrier Carriers’. The Ski Jump ramp had been erected on a strip of concrete to the north of the main runway. So, at infrequent intervals the Harrier-qualified guys would taxi out towards the ramp prior to launching themselves skywards. Lots of data was recorded and no doubt worked on elsewhere to ascertain the best solution for the use of Harrier designer, John Fozard’s, great idea for increasing the Harrier’s payload on take-off. The balance to be achieved was the maximum upwards velocity that could be given the aircraft as against the loads that would be put on the undercarriage as the slope increased. The ultimate angle to be tried was 22°.

  One day several of us were driving past the ramp in the squadron minibus when the Harrier was out being lined up for a take-off using the ramp. What we didn’t know at the time was that this was the end-point of the trial.

  ‘Let’s stop and watch this,’ I suggested. Everyone agreed. We didn’t have to wait long. The Harrier crew went through their final engine acceleration chec
ks and then taxied forward to face the ramp. Having walked out there one day I knew that they were looking at what seemed to be a very intimidating, apparently vertical grey wall. The engine ran up, nozzles fully aft, brakes off and the jet shot forward and was pushed firmly upwards as it rose rapidly up the ramp. Then we all saw sparks and flames coming from under the nose. They’re using rocket-assistance now, I thought. Then I saw something streaming from the underside as the Harrier flew away with the nozzles producing half of the lift. The noise was phenomenal. The aircraft then flew back and we noticed that the main wheels were still down but that the nose wheel appeared to have not retracted fully. We continued to watch as the Harrier flew around overhead for a good ten minutes. It then set up for an approach to land, but not onto the runway. Just to the south of the main runway there was a pit, about 10 yards square, with a steel grid over the top of it. This facility had been built and first used for the very early vertical take-off and landing trials in the early 1960s using a very peculiar aeroplane, the Shorts SC.1. Now the Harrier, with its nose wheel still not down, made an approach to overhead the pit and then descended slowly to land on it. By using what is known as the braking stop position of the four nozzles the Harrier was in exactly the right, slightly nose down attitude to land smoothly on the grid. It was a great piece of flying.

  I later found out that the captain was none other than George Ellis and in the other seat was a recently arrived Aero Flight test pilot, Mike Bell, on his first trip in the Aero Flight Harrier. Mike had been a student at Glasgow and Strathclyde University Air Squadron when I had been an instructor there. What a way to be introduced to Harrier trials flying!