CONCORDE SST - HISTORY

SUPERSONIC PROVING

SUPERSONIC PROVING

At that time it was foreseen that the flying would be shared among seven Concordes ; the two prototypes, the two pre-production aircraft and the first three production-standard aircraft. The first part of the programme would be devoted to development flying to prove the design and to establish the performance characteristics of the aircraft and its systems. When this work had been completed, the programme would continue with certification flying plus route-proving and endurance flying to demonstrate the aircraft's capabilities as a passenger transport.

All the first four aircraft were purely test vehicles and well described as flying laboratories. Each of the prototypes carried about 12 tons of electronic test instrumentation, much of it specially developed for the purpose. This instrumentation was capable of recording measurements of 3,000 different parameters, including pressures, temperatures, accelerations and attitudes, and the information was recorded on magnetic tape in the aircraft for later analysis in the ground data processing centres. While the aircraft was in flight, certain basic information was continuously telemetered to ground monitoring stations.

In the forward part of the cabin in the prototypes were situated the three panels for the flight observers. At these panels the observers monitored the behaviour of the aircraft and engine systems, the information being displayed on instruments duplicating those on the flight deck. Once the initial subsonic handling flights had taken place, a start was made on flutter testing, a necessary preliminary to the transonic and supersonic phases of the programme. Flutter is a phenomenon that can be caused when vibrations of a certain frequency in one part of an aircraft structure set off sympathetic vibrations in another part of the structure. If allowed to continue without damping, the interaction can lead to extremely violent vibration and ultimately to structural fracture.

On October 1, 1969 the first supersonic flight by Concorde was made in 001. The aircraft attained a speed of Mach 1.5 (1,125 mph) and flew supersonically for nine minutes. In general, pilots' reports on the progress of the two prototype aircraft were encouraging. Ground handling characteristics were said to be very good, and there was praise for the ease and precision of control in flight. (This has continued to be a constant feature of pilot reports on Concorde ever since.) When the visor was raised, the absence of noise on the flight deck was said to be impressive, and even, on first experience, rather startling.

It was a measure of the progress made and of the steady growth of confidence in the aircraft, that it was decided to offer four airline captains the opportunity to fly Concorde 001 early in November, 1969, only seven months after first flight. They were Captain James Andrew of BOAC, Captain Maurice Bernard of Air France Captain Paul Roitsch of Pan American and Captain Vernon Laursen of TWA.

After two periods in the Concorde flight simulator at Toulouse, each pilot flew 001 up to the speed of Mach 1.2 (850mph), for which it had been cleared by the flight test programme. They were also free to nominate any of the many types of failure that had been investigated, such as an engine failure in flight or a three-engine landing. In a joint report afterwards the pilots said that they found the aircraft pleasant and easy to fly, that the workload was not excessive, and that they foresaw no problems in training airline pilots and engineers to handle the aircraft.

Mach 2

In November, 1970, both aircraft reached Mach 2 (1,350mph) for the first time, within a few days of each other. In the same month, the 300 hours mark was passed. By this time both aircraft had been fitted with the Oiympus 593B engines, which enabled them to maintain Mach 2 cruise speeds over long distances. This new capability of sustained Mach 2 cruise meant that Concorde pilots were moving into a realm of test flying that had hitherto been unexplored. A Concorde's supersonic flight time is much longer than a military aircraft's supersonic dash, and the design problems arising from high structure temperature are more severe

Most of Concorde's supersonic flying was done over the sea, but special provision had to be made for some overland supersonic flights by 002. For supersonic performance measurements, it was necessary to have a straight line route of about 800 miles, and to safeguard the crew and the aircraft the whole of this route had to be under radar surveillance and within the range of air and ground rescue services. To fulfil these conditions, and at the same time to cause disturbance to the least number of people on the ground, a route was chosen running in a north-south direction over parts of the western coasts of Scotland and Wales, and over Cornwall.

It was made clear that these were test exercises and that it was not expected that more than 50 flights would have to be made, spread over a period of several years. Warning would be given of impending flights, and claims for damage thought to be caused by the aircraft's sonic boom would be considered by the government. As was to be expected, the first flights occasioned a good deal of critical reaction. When first heard, the sonic boom is certainly a startling sound, and, despite the assurances given by the government that this was part of a flight test programme, there were suspicions that this was a plot to "get people used to the noise."

One of the first tests made after Mach 2 had been attained was to check the effect on controllability at this speed of cutting first one engine and then two engines on the same side of the aircraft. Among the gloomy forecasts made by opponents of supersonic passenger transport had been that this type of engine failure would lead to complete loss of control. This test has now been made many times, both with and without auto-rudder, and it has been demonstrated that control is not affected.

The first serious incident in the programme occurred in January, 1971 when 001, flying at supersonic speed, experienced an engine surge which caused one of the movable ramps in the engine air intake to break free. Metal fragments were ingested into the engine, and considerable damage was caused, but all this damage was contained within the engine casing. The damaged engine was shut down and the aircraft returned on three engines to Toulouse where it made a normal landing.

An intensive investigation was made of the incident and its causes, and corrective design action was put in hand to prevent a recurrence. To uncover potential hazards and to eliminate them is one of the main purposes of a flight development programme. This is why, during the development programme, the aircraft is deliberately pushed beyond the limits of its normal flight envelope, and why the most mathematically unlikely combinations of failures are set up for study purposes.

Later in 1971, 001 made the first intercontinental Concorde flights when it flew from Toulouse to Dakar on May 25 and from Dakar to Le Bourget, Paris, on May 26 for the opening of the Paris Air Show. The Dakar-Paris flight of 2,500 miles was flown in 2hr. 52min., including 2hr. 7min. at supersonic speed.

On September 4, Concorde 001 set off from Toulouse on the longest sortie it had so far made from base, a demonstration tour of South America. In the space of 15 days, the aircraft visited Rio de Janeiro, Sao Paulo and Buenos Aires, and made 16 flights. Nearly a hundred South American guests were flown at Mach 2 speeds, and 001 proved itself perfectly capable of fitting into the normal traffic control patterns at airports, even in the very adverse weather conditions experienced on several days during the tour.

It so happened that during 1971, prototype 001 had performed most of the newsworthy feats but the turn of 002 was to come. Throughout that year both aircraft had together built up the total of flying hours, extended the frontiers of knowledge sorted out problems and test-flown the soiutions. In short, they had got on with their exacting and essential task.

The year 1971, when Concorde was spreading its inter-continental wings, saw the end of the rival American SST project. It was finally halted in March by the Senate's refusal to vote further funds. Much of the "credit" for killing the American SST was claimed by the environmentalists, but in retrospect it appears that the real causes of its demise were technical and financial. The emotive crusade of the protest groups provided political justification for action that would have had to be taken anyway.

First passenger reaction

The elimination of American competition in the supersonic travel market did not, however, cause any elation in BAC and Aerospatiale. On balance, it was regarded as bad news rather than good. Leaders of the Concorde project felt that, in the political battles they could see ahead, it would have been useful to have an American SST following close behind. Events were to prove this feeling well founded.

In addition to the South American guests, a handful of other privileged people flew in the two Concorde prototypes during 1971 and so became the first passengers, apart from the test observers and development engineers, to experience flight at twice the speed of sound. Among the first was President Pompidou of France who flew in 001 from Paris to Toulouse, taking in a supersonic section over the Bay of Biscay en route. Later in the programme, the Duke of Edinburgh was to fly in 002 and to take over the controls at Mach 2 for a time.

Press reaction

At the Paris Air Show in May and June, 1971, a series of demonstration flights was made with 001, carrying government representatives, airline executives and influential aviation journalists. One of the latter, Robert Hotz, editor of the well-known American magazine Aviation Week and Space Technology described his flight in an editorial in the next issue of the magazine: "The most sensational aspect of flying as a passenger at Mach 2 in a supersonic transport is that there are no sensations whatsoever that differ from those in the current generation of subsonic jets . . .

"The only unusual internal noise comes during take-off briefly from engine rumble. The cabin noise level without full airline style sound-proofing is about equal to that of a current subsonic jet with only a slight increase near the aft section. Cabin pressurization maintains a constant 6,500ft. environment even during supersonic climb and descent. During Mach 2 manoeuvres only the changing colour of the sky informs the passengers of major banking turns. It is possible and pleasant to walk around during all flight regimes. Stewards will have no trouble serving martinis and meals. Passengers will find no difficulty consuming them. They will just have to drink a little faster - New York will be only a few hours away."

002 also took its quota of passengers on flights from the Fairford flight test centre, either over the Bay of Biscay or the North Sea. These 1,000-mile flights took about an hour and a half and came to be referred to colloquially as "trips round the bay." Since those early flights, one has heard many first-time Concorde passengers trying to put their reactions into words. Some have been eloquent and have spoken of a triumph of the human spirit. Some have been tongue-tied - and yet have been eloquent in their own way, like the Frenchman who came down the gangway and said briefly, "C'est impossible, mais . . ."

World tour preparations

By early 1972, plans were being worked out for the most exacting overseas tour ever undertaken by a development aircraft. The

proposal was to send Concorde 002 on a 46,000 miles journey to the Middle East the Far East and Australia, a 30-day trip that would call for weeks of preparation. It came to be known as the "world tour", a description that was not precisely accurate since it was a halfway-round-the-world-and-back-again tour.

This ambitious exercise was regarded as a logical extension of the flight development programme to date, although there were those who thought that it would have been preferable to wait until one of the later and more advanced aircraft was available. This school of thought regarded it as "counterproductive" (that useful piece of jargon) to send a prototype Concorde so far afield. Because it was an early-development aircraft, they argued, it would give a misleading impression of Concorde in the countries it visited. Its engines were noisier and more smoky than those to be fitted in the series production aircraft. It lacked the range of the later types and could therefore not demonstrate the full capability of Concorde over the long inter-continental routes.

There was much force in these arguments; that was conceded even by those who were for going ahead with the tour. But they believed that 002, prototype though it was, would make a dramatic impact wherever it was seen for the first time. It would demonstrate the great time savings of supersonic passenger flight to the opinion-formers and the policy-makers. It would carry the British and the French flags all over the world. Its shortcomings could be admitted and explained. Application was made for the aircraft to operate supersonically through the airspace of a number of countries along the route. Agreement was reached for such operation in the Middle East, Indonesia and Australia on the understanding that the permission was granted on an experimental basis and that the flights would be made along carefully defined corridors. Most of the civil aviation authorities in the countries concerned made arrangements to monitor the Concorde sonic boom.

Much of the preparatory work was devoted to the logistics problem. After leaving Fairford, 002 would be visiting 14 airports in 12 countries; ground crews and specialised equipment had to be stationed everywhere in advance and spares had to be on hand. The fact that the British government provided logistics support in the shape of an RAF Belfast transport aircraft and a VC10 was seized upon by the ever watchful critics:

"So- much for the makers' claims about Concorde's reliability, it cannot leave its base without support aircraft going along to carry spares for it."

This was a more than usually pointless piece of carping. In airline service, Concorde spares would like those of all other current types, be held at maintenance bases all over the world, and to cope with emergencies, airlines would have spares pooling arrangements. But, although the criticism was not taken too seriously, it was a reminder, if any were needed, that this Concorde tour would take place in the limelight of public attention. Concorde was being shown to the world, and if anything went wrong with the aircraft, the world would soon get to know.

At last came departure day, June 2. The first stop was Athens after a two-and-a-half hour subsonic flight across Europe. Crowds began to gather and the airport terraces were soon crammed with cheerful people. On the airfield blue-overalled Concorde ground crews had established amiable contact with the local crews, a feat they managed to achieve everywhere they went. Aircraft came and went, and in the distance the Mediterranean sparkled in the sunshine.

A promising start

Now watches were being consulted. Time she was in sight, was the unspoken thought. It was the first port of call and a good beginning would be an omen. Technologists, being members of the human race, are no more rational about these things than the rest of us. And there, suddenly, was 002, a speck in the blue sky which set the spectators chattering and pointing. There followed a scene that, with variations was to become very familiar in the next few weeks.

A smooth landing and an informal welcome for the disembarking passengers as the ground crews in the background bustled into action, a Press conference in the airport lounge, with Air Minister Michael Heseltine and flight test director Brian Trubshaw fielding the questions and giving details of the flight; TV interviews; telex messages to base, a lot of bustle but remarkably little confusion. All the detailed planning was beginning to pay off.

In what seemed a remarkably short time, the aircraft was taking off for the next leg, another subsonic flight to Tehran where it was due to be based for three days. Here, to greet it, were more crowds, more sunshine, more work. Next day, on the first of two supersonic demonstration flights, Concorde was honoured by the presence of the Shah of Iran, who occupied the left-hand pilot's seat throughout the flight. This was one of the routes over which special permission had been given for supersonic flying, and after the flight the Shah was complimentary about the calmness and comfort of Mach 2 flying in Concorde. He went further and announced that the national airline Iran Air would be buying Concorde. It was a heartening start to the world tour.

On June 6, the aircraft flew to Bombay, via Bahrain, where it made a three-hour stop to allow time for an inspection by the Ruler, Sheik Essa Bin Sulman Al-Khalifa. On the Bahrain-Bombay sector, 002 had its first chance to prove that it could cut normal flight schedules in half by doing the journey in just over two hours.

On to the Far East

An overnight stop was made at Bombay; a brief halt, but it was planned to stay there for several days on the return journey. Next morning's flight across the Bay of Bengal at Mach 2 brought Concorde to Bangkok in 2 hr. 34 min., cutting an hour and a half off the best subsonic time, and after the short stop at Bangkok, the aircraft flew sub-sonically across Malaysia to Singapore.

Singapore's Prime Minister, Lee Kuan Yew, inspected 002, and his young son and daughter were among the passengers on the first supersonic demonstration flight on June 9. It was at Singapore that, for the first and only time on the tour, technical trouble prevented the aircraft from stick ing to its extremely tight schedule. A snag on the weather radar held the aircraft up for ten hours, and, as it was impracticable to delay arrival at Tokyo, a third Singapore demonstration flight had to be cancelled. However, a promise was given (and kept) that this flight would be reinstated on the return journey.

Environment conscious Japan

Singapore to Tokyo was flown in two supersonic sectors, with an overnight stop at Manila to give the Philippines a sight of the Concorde. Flying time for the journey of about 3,300 miles was just under four hours, again half the best subsonic scheduled time. Tokyo had been regarded as one of the most critical points on the tour. Haneda is one of the busiest international airports in the world, and this first visit by Concorde would be a real test of its ability to fit into a dense traffic pattern. The Japanese are now among the most environment-conscious people in the world, and in this respect Concorde's performance would be carefully studied.

Three landings and three take-offs at Tokyo proved to the airport authorities and air traffic control that Concorde is just another efficient subsonic aeroplane in these conditions. There was the expected newspaper criticism of the smoky exhausts and the engine noise level, but there was also widespread acceptance of the fact that the engine manufacturers were working to improve the Olympus in both these areas. On the first of two Mach 2 flights, members of the Japanese Diet accompanied the chairman and the vice-president of Japan Air Line. Tokyo businessmen and officials also of the national airline inspected 002 on the ground, taking great interest in the electronic test instrumentation.

Heading south on June 15, 002 reached Darwin in a little over four hours' flying time from Tokyo. Arrival at Darwin was delayed for about 90 minutes by the need to replace an air conditioning valve at the Manila transit stop, but this was to be the last significant delay on the whole tour.

After a day's servicing, Concorde flew to Sydney on June 17, along a route that had been carefully planned by the Australian Department of Civil Aviation to avoid townships and Aboriginal reserves. The flight corridor passed near Alice Springs where the boom was measured and its effects studied. It was found that little disturbance was caused to animals, birds or to local inhabitants.

The tour organisers had been warned to expect considerable environmental opposition at Sydney, and groups of protesters had gathered near the Kingsford Smith international airport. They were far out-numbered, however, by the crowds of Australians who had come along in their traditional "give it a go" spirit to see Concorde for themselves. On the approach to land, one of the Concorde pilots saw some of the young protesters throw aside their placards and start waving at the "monster" they had come to protest about.

view in front of the airport terminal buildings, and thousands of people came to walk round the barricade surrounding 002, taking photographs and asking innumerable questions. There was plenty of typically caustic Australian humour, but there was also genuine admiration, often summed up in the words, "She's beaut," and more than one expatriate British family told Concorde men how good it was to see something from the old country they could feel a pride in.

Mr William McMahon, then Prime Minister of Australia, and his wife came to inspect Concorde. Government ministers, Qantas executives and airport officials flew on the two supersonic "demos" from Sydney, the second of which took the aircraft, after a wide sweep over the Tasman Sea, to Melbourne. Here, two more flights were made and the names of more distinguished passengers added to the list.

Back home

Melbourne was the turning-point. From there on 002 would be homeward bound. In the 20 days journeying from Fairford, the outlook of the Concorde support party had undergone a transformation. The "fingers crossed" attitude of the first few days had given way to complete confidence in the aircraft and her crew. All the reservations and the doubts were forgotten. Most important of all, perhaps, was the knowledge that everywhere Concorde went the ordinary men and women in the street were "on our side."

On June 22, Concorde flew back along the same supersonic corridor to Darwin, and then on the following day to Singapore where the promised demonstration flight was organised. Taking off from Singapore on June 25, the aircraft flew to Bangkok and on to Bombay. The crossing of the Bay of Bengal was made supersonically at 54,000ft., just above the monsoon storm clouds. To cross India, 002 slowed to subsonic speed although it is doubtful whether its boom would have been heard among the thunderstorms.

The next leg was to Dhahran in Saudi Arabia where, on a demonstration flight, HRH Prince Turki Bin Abdul Aziz and high Saudi officials enjoyed their first experience of flight at twice the speed of sound. At the next stop, Beirut, the last supersonic demonstration flight of the tour was made for government officials and executives of Middle East Airlines. The flight from Beirut to Toulouse on June 30 included the longest overseas sector of the tour, and the 2,400 miles was flown in 2 hr.

19 min. Beirut-Toulouse is not at present an airline sector, but it might well become one in future Concorde operations.

Precisely at noon on July 1, Concorde 002 landed at London Heathrow, spot on time after a well-nigh faultless month of intensive worldwide operation in a variety of environments and extremes of climate. The last Press conference was held, the last questions answered - and the general verdict was, "Good show." Thousands of people travelled to Heathrow on the Sunday to see Concorde, and on Monday morning came an unannounced visit by the Queen and Princess Anne, a signal honour to mark the conclusion of the tour.

By the end of 1975, when it is due to enter service, Concorde will have been under development for 13 years. That is about twice the length of time forecast when the project was begun. Those predictions were made in good faith, however. That the problems ahead proved far more complex than had been visualised is part of the risk that nations take when they launch on a project as advanced as Concorde. After all the Soviet Union, with their vast aerospace industry and impressive achievements in space, have nevertheless taken much the same time over their SST project.

The fare structure

The long development period has created special problems for Concorde. Air travel has changed dramatically in the intervening years. The slow growth of business traffic came to a halt around 1967. Stagnation in the business travel market was accompanied by a steady growth of leisure traffic as promotional fares - filling seats by enabling tourists, students and parties to preferential rates on giving fairly long notice - became more and more attractive.

By the early 1970s, the promotional "tail" was wagging the full-fare "dog." On the North Atlantic routes it was calculated that business travellers, representing about 30 per cent of the total traffic, were producing about 60 per cent of the total revenue. For scheduled airline operators, another factor in the deteriorating situation was the rapid increase in competition from charter operators over the last ten years or so.

In 1975, therefore, the situation is totally different from that in 1962 when Concorde's manufacturers were making the first market studies. Long-haul air traffic has been transformed from mainly business travel to a mix of leisure and business with the numerically smaller proportion of business passengers providing the greater part of the revenue. In addition, since the introduction of the wide-bodied Jumbo jets, airlines have faced a problem of over-capacity far exceeding anything previously known.

How has the transformation of the market affected the saleability of Concorde? Concorde's greatest asset is its speed, its ability to get you there in half the time, but there was a practical restriction on the use of that speed, the sonic boom. A detailed study of the world's long-distance route structures and the volume of traffic they carried, showed that about 73 per cent of all inter-continental seat-miles were produced over the oceans and, with minor rerouting, another seven per cent could be added to this total. That was reassuring, for there is no sonic boom problem over the seas. (On its world tours, Concorde has over flown thousands of ships of all types and there has never been any adverse report on its boom.)

Gradually there evolved what came to be known as the "mixed-fleet" philosophy. Hitherto, the main classification of air transport has been the standard of cabin service offered. For a premium of about 60 per cent over the economy fare, the first class air traveller gets rather more elbow room and leg room, free drink and more elaborate meals, but (and this is the crux of the Concorde philosophy) he does not get to his destination any quicker than the economy traveller. One flies to save time, but the first-class traveller does not save any more time in return for his higher fare.

Time is money

In introducing Concorde, the operator could for the first time offer the first-class traveller something for his money; hours of extra time. Those who travel first class are not usually fare-conscious, but they are time-conscious and would welcome those extra hours. Many of the economy-class business travellers could also be expected to opt for Concorde. For them or their companies there would be a simple question to be asked: is the value of x hours of Mr A's time worth more than the Concorde fare premium? And if the answer were "yes", then he would travel Concorde.

What is needed, according to the mixed fleet philosophers, is that the big subsonic jets are also configured as single-class vehicles. At present, every first-class seat in these aircraft is occupying space equivalent to about two-and-a-half subsonic seats, and this uneconomic use of space is one reason why the wide-bodied jets have not fulfilled the early promises of reduced operating costs. If they were laid out as economy class throughout, their operating economics would be greatly improved.

On suitable routes, the two types would provide complementary services, and each would be operating in a role for which it was designed, the supersonic aircraft offering the speed and convenience that the business traveller requires and the subsonic aircraft the low-cost travel that the leisure market requires. Whereas in the past the two stimuli to traffic growth - higher speed and lower fares had been provided by one new type of aircraft, now they would be supplied by two separate types.

Making what appeared to be reasonable assumptions about the load factors which might be expected for Concorde and the wide-bodied jets operating in harness in this way, the supersonic salesmen were able to demonstrate that the overall profitability of the mixed fleet would be better than that of an all-subsonic fleet with the same total seating capacity. To achieve this result, it could well be necessary to reduce frequencies on the subsonic services, but this could be done without causing hardship to the leisure traveller (subsequent economic pressures have indeed compelled airlines to reduce frequencies and to coordinate services).

It was a well-reasoned argument, and if it could be proved, the end result would be better service, not just for the air travel elite, but for the whole range of passengers by air. This would spike one of the main criticisms: that Concorde would benefit only the privileged few.

Aerospatiale and BAC decided to mount a professionally-conducted survey in the USA. Nearly 300 business travellers, all of whom had made at least two overseas trips in the previous year, were interviewed at New York, Chicago, Los Angeles and San Francisco. An important aspect of this survey is that it covered the reactions to both single-class and mixed-class Concorde cabin layouts.

The survey showed that on Transatlantic and Trans-Pacific routes, more than 90 per cent of first-class travellers would switch to Concorde at first-class fares, and, even at first-class plus 50 per cent, 85 per cent would still travel Concorde. On the West Coast Hawaii route, there was more resistance to this higher premium fare, but if a mixed class layout were used on this route many present first-class travellers would elect to fly Concorde economy and a high total switch to Concorde would still be achieved.

As expected, economy-class travellers showed themselves more sensitive to fare levels, but even so, there would be a changeover to Concorde by more than 30 per cent of business economy travellers on the North Atlantic routes and by more than 50 per cent on the Pacific routes. Only a very small number of those questioned commented adversely on Concorde's relatively small cabin, and the great majority clearly regarded this as being more than offset by the time savings. On the basis of replies from these travellers it was estimated that the introduction of Concorde would lead to an increase in business travel of between 13 and 17 per cent, depending on fare level.

These results confirmed the previous BAC-Aerospatiale estimates of market penetration arrived at by statistical analysis, and they clearly supported the mixedfleet philosophical arguments. A market survey is, of course, always open to criticism on the size of the sample and the framing of the questions, and this survey was not entirely accepted in airline circles. However, the results were agreed to be a significant pointer to the acceptability of supersonic travel. In 1975 another survey was conducted among Japanese business travellers with the close co-operation of Japan Air Lines, and the results were almost exactly the same as in the American survey - the passenger appeal of speed is irresistible and there will be a demand for Concorde travel even at premium fares.