Flight Testing to Win: An autobiograpghy of a test pilot

By Tony Blackman

No aircraft is absolutely safe. This book is about Aviation, from learning to fly, becoming a test pilot, flight testing, demonstrating on some of the third world's worst airfields, then specializing in Avionics and finally joining the Board of the UK Civil Aviation Authority, helping to formulate the regulations that the author had spent so many years living by. Many stories are told, including flying with the legendary Howard Hughes when the world thought him a mad recluse, and testing many aircraft including all three V Bombers, an almost unique experience. The book, well illustrated, makes the point that flying is inherently risky, that regulations always try to quantify acceptable risk, that safety is a cost, and that test pilots have to sell their aircraft and should not try to make an aircraft safer than the rules require. It emphasizes the almost unbelievable changes in aviation in one working lifetime, whilst painting a picture of a much simpler world, now gone beyond recall.

• Language: English
• Publisher: Blackman Associates
• Release date: Sep 30, 2005
• ISBN: 9781612001746

Tony Blackman

Tony Blackman has spent his life in the aircraft industry as a test pilot, as an avionics specialist and then on the Board of UK Civil Aviation Authority as the Technical Member.

Book preview

CHAPTER 1

Learning to Fly

Some people in life seem born to fly. They yearn, almost it seems from when they are born, to pilot an aircraft. It is their driving ambition and they are emotionally involved with everything involved with aviation. I was not one of those people. In my formative years at school, during the 1939/45 Second World War, the thought of flying an airplane never occurred to me. I watched with horror as some of the United States bombers returned damaged from Germany, emitting smoke, and landing on the many airfields surrounding my school at Oundle in Northamptonshire; the airfields are now deserted but some names I shall never forget --- Polebrook, Molesworth, and Deenethorpe. I still remember seeing the planes that did not make it, crashing in the countryside nearby, not really appreciating the terrible human tragedies that were occurring.

It is strange that though I eventually spent my whole working life in the aerospace industry, I was not the slightest bit interested in aviation whilst at school or college. My involvement with flying was purely an accident and I have often wondered what finally motivated me to get involved with aeroplanes. It might have been significant that every summer in the 1930s we spent our holidays at Westcliff-on-Sea in Essex. My mother got rid of me for the week by paying the local boatman, who made his living taking holiday makers sailing off the beach, the then not insignificant sum of two shillings and sixpence to take me on as his helper. I learnt about sheets, booms, anchors, tides and many other skills. More importantly, I learnt how to trim sails into the wind and how to steer a sailing boat. Sailing was my first experience of aerodynamics and the effect of wind and tide. I did not sail again until I was at College.

My prowess in matters educational, before I reached my 'teens, was abysmal. My local day school was evacuated to Devon twice, the first time in 1938 to a guest house in Dawlish when another World War seemed inevitable. The Prime Minister came back from Germany with a ‘piece of paper’ saying ‘peace in our time’ and so we all returned home. We went back to Devon again in 1939 to Luscombe Manor when the war actually started. I can still remember listening to Neville Chamberlain's speeches both in '38 and again in '39 when he announced the invasion of Czechoslovakia and the declaration of war. To us at school the threat of war or even war itself meant very little. My parents tried very hard to find a school which would teach me properly and improve my education and in 1940 they sent me to an expensive private school, Downsend School in Leatherhead in Surrey. Here the teachers made serious efforts to educate us because, I realised some years later, it was vital to get good results to the so called Public Schools, actually privately run, in order to ensure that parents were willing to pay to send their children to the school. No sooner was I settled in Downsend than we were evacuated, this time to Hurstpierpoint Public School in Sussex, further from London but actually closer to the war and the enemy aircraft.

I loved being at Hurstpierpoint, set in the Sussex countryside with lots of Victorian and Edwardian buildings, housing the boys and the classrooms. There, at the age of eleven, I unexpectedly developed an obsessive interest in mathematics and this obsessive streak in my character has never left me, though the obsession drifted from mathematics into computing. Thanks to Mr Straker, the maths master at Downsend, I managed to get a major scholarship to Oundle. He introduced me to Lancelot Hogben's Mathematics for the Million and I was enthralled. His book taught me differential calculus at an early age and, like learning any language, the earlier one starts the easier it is to assimilate. Hogben followed his first book with Science for the Citizen and again he opened my eyes to concepts that I had never imagined. To this day they are still my favourite reference books, together with the three text books my maths master, G.W.Brewster, wrote at Oundle.

I remember my excitement as my mother bought all the clothes required by Oundle, listed in detail by the school’s administration. Every article of clothing had to have a tag sewn on to it bearing my name and the ‘house’ where I would be accommodated whilst in the school. The war was causing shortages so things were not all that easy to obtain. The great day finally came; all the parents arrived at Euston with their offspring and off we went in a special train direct to the station at Oundle. I was in New House, one of eleven houses at the time and, of course, it was the oldest house in the school.

Oundle School was wonderful for me. Mr Brewster taught me for the four years I spent there and I enjoyed every minute of his lessons, much to the amazement of many of my school fellows. I was very fortunate that I was able to assimilate mathematics with incredible ease but, after two years, I decided to concentrate on Science as being a more practical discipline. I developed an interest in electronics which I found very demanding theoretically but which, I realise now, was very time wasting practically and, rather like a disease, it started to blunt my academic skills. Luckily the blunting proceeded slowly and, as the war ended in 1945, I went up to Trinity College, Cambridge with a major entrance scholarship to read Physics with my anticipated future quite clear; to get a good degree and do research as befitted a scholar. But somehow things did not work out as planned and I was called up into the Royal Air Force for two years National Service.

In October 1948 I went to Padgate near Liverpool, as many thousands of recruits before me had done, to do ‘square bashing’ and to learn how to be the R.A.F. equivalent of an Army private. Of course, for me and the others who were with me, it was a special situation because we had all been pre-selected to become officers in the Education branch. As we finished at Padgate we went on to the Officer Cadet Training Unit at Spitalgate in Lincolnshire to be trained as Officers. It was an interesting course and twelve weeks later we emerged as Pilot Officers ready to be trained as teachers. We went on to Wellesbourne Mountford, where the R.A.F. School of Education was based. The students on our course came from many disciplines but we all had to learn that just having a degree was not an immediate passport to becoming effective teachers. After twelve weeks we were judged ready to be let loose on our students; our training as teachers was, of course, rudimentary, but we managed because we had a depth of knowledge in our various subjects.

As the course came to a close our chief instructor discussed with us the various postings that needed to be filled. I cannot remember all the choices for the few science graduates on our course but I was attracted to a post at Wittering since it was only 100 miles north of London and therefore convenient for my social activities. The job at Wittering was to teach mathematics and physics to students who were to become pilots and navigators but, at the time, this fact made no special impact on me. I asked to be sent to Wittering and, as luck would have it, my request was granted. I was posted to No. 1 Initial Training School to become an instructor, my first real job. So, in this casual way, my life and career was settled!

Wittering appealed to me. It was one of the R.A.F. stations built between the two world wars with standard buildings, hangars and an Officers Mess where all the unmarried officers lived. It was near my old school, near Cambridge and not too far from London. The place was on the Great North Road and, by modern standards, the traffic was very light. I was lucky enough to have an old second hand car so I was able to tour the area, though petrol rationing was still in force after the war so I could not go far. The airfield had been used during the war but there were no runways as such; however there was a grass strip nearly two miles long which was a magical place in many ways. I loved getting up early in the morning when I was going to London, harvesting the mushrooms from places where, twelve hours before as night fell, there was absolutely no sign of any; their speed of growth never ceased to amaze me. Unfortunately, due to the drive of technology, it was not many years later that an enormous 10,000 ft runway was constructed on the airfield with runway lights and approach lighting for the V bombers that I was later to test, but luckily at that time we had no inkling of what was going to happen. I often wonder whether the mushroom grounds are still there or whether they have been covered with concrete.

My job was to take over from a Flying Officer Hague, a National Serviceman like myself, to instruct in mathematics and physics pupils who had been selected to be trained as pilots or navigators. The pupils mainly came from volunteers who had the necessary academic qualifications and wanted to make the Royal Air Force a career. However, there were a few National Service pilots on the pilot courses who had already been trained in the University Air Squadrons. All the students had had to go to Hornchurch where they had been subjected to a battery of aptitude tests to determine their level of intelligence and to find out whether they would be suitable as pilots or navigators. I am not sure how effective the tests were or how much weight the R.A.F. accorded the results but, as I learnt later myself, the tests were very different from the normal academic exams I had been used to, requiring the student merely to select an answer from several choices. Such tests, which do not test the ability of the student to write coherently, are commonplace to-day but at the time they were very new.

Hague showed me the syllabus, sample lectures and the exams he was setting at the end of the course and, after listening to a few of his lessons, I started teaching some of the courses myself. I found that quite a few of the students did not have the necessary mathematics to be able to complete the course and I had to spend a lot of time teaching things like basic trigonometry. The academic range was very large on the courses and it was a challenge to keep the interest of the students who had either passed mathematics at Advanced Level at school, or had degrees. After I had completed the first few courses the lectures became routine but it was fascinating meeting all the different people and hearing their ambitions for the future. Most of them, obviously, wanting nothing more than to learn to fly.

Some of the other instructors at Wittering were ex-pilots and navigators and had joined the education branch because of a loss of medical category. In addition, there were some current pilots and navigators who were posted to Wittering to be in charge of the courses going through the system.

Airspeed Oxford

Occasionally an aircraft would land on the airfield and give the pupils air experience and I remember flying with a Flt. Lt. Bethell in an Airspeed Oxford, an ancient twin engined aircraft with a tail wheel and an appalling view from the flight deck. I don't think the event made a great impression on me one way or another. I certainly enjoyed looking down on the long green airfield as we slowly flew around the area, slowly being the operative word. It was at about this time that I began to wonder what the future held in store for me. My father had arranged for me to train as an accountant but the idea was not very appealing to say the least. For some reason my aptitude for mathematics did not spill over to managing money.

I cannot remember when exactly I decided to stay in the R.A.F. and become a pilot. I know that we had some visits from senior officers and some of the visitors suggested that I should convert from being an Education Officer and take a Permanent Commission. Unlikely as it seems, even at that time I realised that my training at University could be very valuable in helping me to become a test pilot, because most of the experienced and famous test pilots of the time had been trained in the war and had just not had the opportunity for academic training. This lack of training did not matter much then, but times were fast changing and I could see that aircraft design was moving rapidly from an art to a science and that test pilots needed to be able to talk the same language as the designers and engineers. Of course, though I did not know it at the time, the powers that be in the Royal Air Force had come to the same conclusion rather earlier, so that in 1943 the Empire Test Pilots School had been formed under the command of Sammy Wroath, an outstanding leader in the test piloting fraternity. Fifty years later, at the half century re- union of the Empire Test Pilots School Sammy, on the wrong side of eighty years old, gave the keynote speech without referring to any notes let alone the modern love affair with Powerpoint, an outstanding performance by any standard.

I considered my options and realised that I did not relish returning home and having to learn to be an accountant. I was enjoying my first job, earning some money and being able to decide what it was I really wanted to do. Somebody pointed out to me that if I did transfer to the General Duties branch and apply for a Permanent Commission I could enrol as if I had been a member of the University Air Squadron, which meant that I would get accelerated promotion. I decided to take the plunge and I was sent to Hornchurch to check on my aptitude to be a pilot. Of course I was very lucky; I was born at the right time and, by chance, was in the right place to have the opportunity to fly and, moreover, something training could not supply, I had excellent eyesight and wa physically fit. In due course I was informed that I would be accepted as a student pilot and so, at the beginning of 1950, I found that I was posted to No. 6 Flying Training School at R.A.F. Ternhill in Shropshire, to join one of the courses I had just finished instructing, No. 38 Pilots Course.

***

Ternhill was very different from Wittering. I was a pupil once again, albeit a privileged one, since I was the only member of the course who was already commissioned. I shared a room with another student officer pilot, Flying Officer Erik Bennett, who had joined No. 35 Pilots Course, the Ternhill course before ours. I had not met him before as he had been posted straight to Ternhill and had not been to Wittering. He had already gone solo and was mad keen on flying. He was also well connected locally and, together, we visited some of the local landowners in our spare time. He was very determined in everything he did, a trait that I have noticed in people who are not very tall. I was not surprised to discover in later years, long after I had left the R.A.F., that he had become an aide to King Hussein of Jordan. In fact Erik became a very senior and distinguished Air Force officer, specialising in the Middle East and finished his career as Chief of the Sultan of Oman's Air Force. To me he seemed very much in the mould of Lawrence of Arabia, quite rightly loved and respected by the senior rulers and airmen of the Gulf States.

Because I had not been a student on 38 Course at the Initial Training School, I had not received instruction on all the many subjects that needed to be learnt to become a pilot. It was necessary for me to catch up quickly with the rest of my course and learn about matters that had never previously interested me, like how an internal combustion engine worked, about navigation, about meteorology and a host of other matters. I thoroughly enjoyed exploring these practical subjects, though the knowledge I gained never really turned me into an engineer; I always considered everything I did from an academic viewpoint and I was not used to putting precept into practice. Looking back, I probably asked too many questions but, like most people, the instructors responded to the challenge and my curiosity probably made their job more interesting.

In parallel with our Ground School we were introduced to our first aircraft, an ab-initio trainer, the Percival Prentice and to all the supporting services that were needed to be able to fly in the R.A.F. We soon learnt that there was no question of flying a working aircraft merely for enjoyment; in later years as Chief Test Pilot I had to remind some my staff of the same thing. Furthermore, we soon came to realise that safe flying is only possible if there is an infrastructure to support the aircraft. First and foremost an aircraft has to be maintained properly. It consists of many parts, the engine, the flying controls, the navigation and radio equipment, the instruments and, nowadays, many other systems. On the course, we learnt that a serviceable aircraft only happens as a result of a lot of hard work by the ground crews. Every day, the flying programme was put on the board with our names, our instructors and the aircraft, but without the hard work and skill of the ground crews, it would never have happened.

We needed to learn about the weather and the way the Meteorological Office provided all the data to help pilots determine whether it was safe to do the flight that was planned. We were introduced to miles of paper printout, which showed us the conditions at the airports all over the country and the synoptic charts that attempted to forecast what would happen next. We had to recognise when the weather forecast was likely to be correct and when the conditions made it much harder for the forecasters to be certain of the future. In our slow aircraft, winds were very important not only near the ground but also en-route and we had to be able to calculate the effect of the winds using a so called ‘Dalton computer’. This was a device which could be strapped on one’s knee, enabling graphical triangular solutions of drift and ground speed from estimated wind and airspeed. Rudimentary by modern standards possibly, but very effective.

It is not permissible now and it was not permissible then to just get into an aircraft and go. At a training airfield in particular there were hundreds of take-offs and landings a day and there was a control tower to watch over us. In fact we soon learnt that Air Traffic Control watched over us not only at Ternhill but wherever we were flying. We had to learn the Rules of the Air, how to behave in an airfield traffic pattern, how to navigate from one place to another and how to file a flight plan, when one was required, and how to keep air traffic informed of the destination of the aircraft. There was the operation of the radio to master so that we could tell the air traffic controllers of our immediate intentions or what had happened to us. Above all we had to learn to keep a good look out, whether we were on the ground or in the air. We also needed to watch the signals that the controllers had put next to the control tower to show, amongst other things, which way the aircraft had to fly around the circuit.

Percival Prentice

The Percival Prentice was the main ab initio trainer at the time in the R.A.F.; a low wing monoplane, non-retracting landing gear with a tail wheel and a de Haviland 292hp Gypsy Queen 32 inverted in-line piston engine. We were given the Prentice Pilots Notes to study. Each aircraft type in the R.A.F. had its own Pilots Notes and the Prentice was no exception. These excellent books were written by the R.A.F. Handling Squadron, then at Hullavingon, and I got to know the unit very well in later years when they moved to Boscombe Down. It seems incredible to-day, but the Prentice Pilots Notes had just twenty eight small pages and some illustrations. Not surprisingly it did not take us long to learn about the aircraft and its limitations; maximum dive speed 215 knots, maximum speed with flaps down 75 knots, maximum weight 4,200 lb., full fuel 20 gallons of petrol in each wing and no fire extinguisher if the engine caught fire.

The crew seating arrangement was side by side which was obviously good from a training viewpoint since the instructor could see what was going on and point things out to his student. However, I was reminded of a remark by Uffa Fox, a famous yachtsman of the time, whose books I used to enjoy reading. He pointed out that in building small boats it was difficult to absorb the space required by a yachtsman without distorting the aerodynamic design of the boat and, of course, the same is true for a small aircraft. For this reason, from a performance viewpoint, tandem seating is best in a small trainer but, of course, it is then difficult for the instructor to monitor the pupil properly since the pupil is out of sight. The Royal Air Force policy makers had decided in their wisdom that side by side seating was to be preferred and the Prentice was the first post-War example. The aircraft had had to be made very wide to accommodate the two seats and the result was that it was under powered, heavy, ungainly and slow since, not surprisingly, the engineers at Percivals had been unable to design the Prentice to escape from the limitations resulting from the design requirements. The Prentice was as uninspiring to the instructor as it was to the student though, as students, we did not then know any better. It was an enormous contrast to the famous biplane trainer, the Tiger Moth of pre war years, and the de Haviland Chipmunk, a relatively modern trainer aircraft at the time, not penalised commercially by the need to meet the R.A.F. requirement of side by side seating. The R.A.F. soon realised the shortcomings of the Prentice and specified a new trainer which resulted in the Percival Provost, another side by side seating aircraft, but with a much more powerful radial engine, the Alvis 550hp Leonides; the aircraft was able to be larger so that the side by side seating drag penalty could be partially absorbed by having a wider fuselage. The Provost started to replace the Prentice in 1953. I managed to fly it some years later - it was a delightful aircraft; I wish I had had the opportunity to train on it.

As the Prentice had a fixed undercarriage there was no need for a system to retract the landing gear. However, the wheel brakes were operated by pneumatics, a feature that seemed to have endeared itself to UK aircraft designers, unlike the United States manufacturers who preferred to use hydraulics. The Prentice brakes were operated by pressing a lever on the hand wheel. which slowed the aircraft down if the rudder was central. To turn the aircraft the brake lever was depressed with the rudder displaced, which introduced differential braking to the wheels and, therefore, altered the direction of movement of the aircraft on the ground. The pneumatic braking system did not work well on the Prentice, or on any other aircraft that I have flown for that matter, and it never ceased to amaze me how long it took before British designers finally faced up to the fact, which all pilots who had flown US aircraft knew very well, that hydraulic brakes were much more reliable and much easier for the pilot to use to control the aircraft.

Landing flaps were fitted to the Prentice, also operated by the pneumatic system. The flying controls, ailerons and elevators, were unremarkable, operated by a stick moving cables. The aircraft had one VHF four channel radio set, the frequencies being pre-set and controlled by crystals. This feature, which was standard about this time, meant that all flights had to be planned very carefully to ensure that it was possible to talk to the necessary airfields and navigation agencies. One of the arcane mathematical feats that all pilots had to master was the calculation to determine the frequency of the crystal required to be fitted in the set, to get the desired VHF frequency. If the calculation was incorrect, the only possibility was to talk on the international distress channel, 121.5 Mc/s as it was called then, now 121.5 Mhz, but this understandably was very much frowned upon unless, of course, there was a real problem. We had to learn what to do if our single radio set failed, how to alert the tower by waggling our wings and how to read the circuit instructions which were laid out next to the Control Tower. We relied on the Aldis light signals, red and green, to know when it was safe to land. It all seems prehistoric now but then it was absolutely normal, not worthy of comment.

The only other radio we had on board was an aid to help us to land in bad weather. It was called the Standard Beam Approach, SBA; though the system and technology seem archaic now, it was definitely a vital bad weather approach tool at the time. The design principle was that there were two antennas on the ground, one transmitting dots and the other dashes; on the left hand side of the runway centre line on the approach you could hear dashes on the radio receiver and on the right hand side of the approach only dots. On the runway centre line the dots and dashes merged so that all the pilot could hear, in theory at any rate, was a steady note. However, the problem was that the sets were not very reliable and the tuning mechanism was extremely poor to say the least. Each airfield had a different frequency for transmitting the signals and there was a different morse code identifier for each airfield. The pilot had to crank a handle driving a very inefficient cable connected to the radio box and listen to the noises on his earphones; there was no reliable indication of tuned frequency since there was not much connection between the needle indication on the tuning indicator and the frequency being received, so it could take a long time to find the signal and check it came from the right airfield. The volume from the set was low and the range of the equipment was poor so it was always a nerve racking business getting tuned in, particularly when the weather was bad and the system was really needed.

The method of using the SBA was to get headings to steer from the control tower until the aircraft had passed over the airfield. The plane was then turned on a timed downwind leg until it was considered that it was six or seven miles away from the airfield. It could then be turned towards the beam and the pilot would listen to the dashes waiting for the noise to change as the dots would come in until a continuous note was heard, the dots merging with the dashes. The turns had to be judged from experience in order to reach and hold the centre line, allowing of course for the wind. If all had gone well a fan shaped beacon called the outer marker would be heard at about five miles out; altitude could then be reduced slowly down to an approved minimum height. The aircraft would be levelled off, the inner marker would be heard and then, hopefully, the runway would appear out of the gloom; if not the aircraft would be put into a climb and either another approach commenced or it would be diverted elsewhere. Old fashioned as the system was, it never ceased to surprise me how effective and useful the SBA was. I realise now that it only worked as an approach aid because the aircraft approach speeds were so slow.

Prentice Instrument Panel

The instruments on the Prentice were duplicated, one set for the instructor on the right and one set for the trainee in the left hand seat. The main instruments conformed to the standard layout at the time with the airspeed indicator on the left, artificial horizon central and the altimeter below the airspeed indicator; the vertical speed indicator was top right with the turn and slip indicator below. Interestingly, the standard layout changed in the next few years so that the altimeter and the vertical speed indicator changed places. The change was probably due to the fact that civil airliners had that layout and the Royal Air Force decided to conform.

The engine instruments were centrally located between the two sets of blind flying instruments. In those days the artificial horizon was driven by suction and the instrument could be 'toppled' or lose its orientation if the aircraft climbed or dived vertically when carrying out aerobatics Consequently, it was important to know how to fly using just the turn and slip indicator. For training purposes the aircraft was fitted with blue screens which we could put up in front of the windscreens and we were able to practise instrument flying by wearing amber goggles. This trick enabled us to see the instruments but ensured that we could not see outside to get visual cues; the system was not perfect but it worked reasonably well.

Keeping the directional gyro pointing the right way was very important if you did not want to get lost. The problem was that all gyros, then and now, tend to drift partly due to the imperfections of the gyro itself and partly due to the rotation of the earth, since the gyro axis of rotation is fixed in space. The only heading reference of the aircraft was the magnetic compass but the magnet, and the card that was fixed to it, only pointed at the magnetic north if the aircraft was flying level in un-accelerated flight. It was necessary to synchronise the directional gyro heading to the heading of the magnetic card every few minutes to ensure the heading being followed on the directional gyro was correct. Whilst on the ground, it was easy to turn the gyro control knob to the indicated heading of the magnetic card but, once in the air, the magnetic card would wander all over the place so precise flying was required to get an accurate heading from the magnetic card before updating the gyro. If one forgot to set the card then the aircraft would enter a large curve, taking the unwary pilot away from the desired destination.

As students we had so much to learn that it never really occurred to us that the Prentice left a lot to be desired. Our instructors knew that the aircraft was pedestrian but it did not worry us. We were immersed in learning everything that there was to know about it. Each time, before we got anywhere near flying, we had to walk round the aircraft to make certain that the control locks had been removed, that the control surfaces moved freely and that the pitot head cover had been taken off so that the airspeed indicator and altimeter would work. In winter we had to make certain that there was no ice or snow on the wings. When we had finished our external inspection we climbed aboard and connected our parachutes which we had had to carry out to the aircraft with us. It was many years before I had the luxury of flying in an aircraft which did not require a parachute and, though I accepted the need for it and carried out all the drills, thankfully only on the ground, I always felt that the perceived need for a parachute definitely spoilt the enjoyment