JUMBO THE GIANT NEW JETS ARE STUMBLING TO GREATNESS

Press, Volume CIX, Issue 32219, 11 February 1970, Page 12

JUMBO THE GIANT NEW JETS ARE STUMBLING TO GREATNESS

(BV

MICHAEL DONNE,

in the "Financial Times." London)

(Reprinted by arrangement)

You know that you are going to experience something different from the moment you get your boarding pass at check-in. Instead of the customary card, Pan American gives you a bluecovered folder to hold your ticket, with a colour-code on the back—purple, white, red, gold and orange. They correspond -to the sections of the aeroplane—purple for first-class, the rest for the economy-class “salons.” Your seat number is written against a colour, and as you board through one of the three doors on each side used for loading (there are up to five doors each side, if needed), one of the 14 stewards and stewardesses directs you to your seat.

Michael Donne, aeronautical correspondent of the “Financial Times,” London, after 12 hours of Jumbo flight, looks at the new jets.

It Is really like entering a (private theatre. If you enter (by a forward door and look | back, a sea of gaily-coloured I seats swims away for 62 yards ! towards the tail, the old “tube” look of passenger 1 cabins eliminated by the (various galley and lavatory areas that interrupt the cabin. There are two aisles, [and the seats are arranged so that only on one side is there that old horror, the three-abreast configuration. In the centre, between the aisles, and on one side, the seats are two-by-two, so that getting in and out is easier. The triple-seating is only on the port side, and Pan American says the middle seat of the three is the one assigned last. All the seats are 10 per cent wider than before, and each one has an [arm-rest that can be flipped up to give more room. To add to the air of spaciousness, the 20-foot-wide cabin is also several feet higher than in a 707.

More Comfortable

It all sounds wonderful. The reality is somewhat less than that, but having now i flown in the Jumbo for the [grand total of 12 hours, covering some 8000 miles or more, including a United States trans-continental and an Atlantic overnight flightin economy-class seats—l can vouch for the fact that the wider seats are more comfortable, although they do not recline quite enough for my liking. The engine noise level is lower than in 707 cabins, especially in the forward sections, and although still obtrusive in the rear sec tions, it is nowhere near enough to drown conversation, or make it painful, as in the rear section of a 707. Indeed, the sound of passengers chattering may become one of the new sounds of aviation in the 747. The aisles and spaces beside the doors and galleys and lavatories (there are 12 of those, in my view still not enough, (especially on an overnight (flight in a fully-laden airI craft) do make it possible to i circulate more. But one brilliant innovation deserves high praise—every pair of seats has its own numbered “locker” close (to the ceiling, numbered so that there can be no mistakes. They are strong, swing: down smoothly and can take coats, handbags and all but the very heaviest bric-a-brac] hand baggage that passengers bring on to aeroplanes.

How Reliable?

So much for the aeroplane from the comfort point of view. But the question that must arise in the light of the publicity given to the troubles it has encountered so far is: how reliable is it? Many of the snags that have been encountered with the aeroplane—such as the faulty cabin doors that proved difficult to shut (which upset an early flight from London) and faulty cabin electrics—are no more than the teething troubles expected on any new aeroplane. Even so, Pan American feels that it is getting rather more than it would have liked or deserves. The other problems have been more serious, and revolve around the big Pratt and Whitney JT9D-3 turbofan engines, each of which delivers 43,5001 b of thrust. The original problem was that of a minute distortion, stemming from the way the engines were mounted on the wings. This distortion, called “ovalisation,” robbed the engine of some thrust and caused fuel consumption to rise under certain hotweather conditions.

Solving it—and it has now been solved —took several weeks of hard work, and caused a delay in deliveries of aircraft to the airlines, in turn delaying the start of passenger services. The modification involves fitting a “yoke” or “thrust-frame” on to the engine, which helps to spread the load and thus eliminates “ovalisation.” When I walked down the Pratt and Whitney assembly lines at East Hartford, Connecticut, recently, I saw stacks of “thrust-frames” waiting to be fitted on to engines as they moved along the line, and Pratt and Whitney is now delivering to Boeing modified engines incorporating this device.

Safety Unaffected

Some of the Jumbo jets built so far are being delivered to airlines without this modification, but will be fitted with it later. The aircraft are quite safe: the problem does not affect safety, but does involve economic penalties in airline operations. The Jumbo which made the Atlantic inaugural passenger flight was fitted with “unmodified” engines. The new engine problem that has now arisen also does not create a safety hazard, but does cause severe operational problems. It' delayed the inaugural flight 6] hours out of New York, costing Pan American a few passengers who rebooked to Lon(don on to other airlines, but

in London it cost the airline a lot more passengers—l2B —who declined to wait for the incoming Jumbo that [was due to take them to the United States. What is so worrying for Pan American, and other 1 would-be operators of the Jumbo, is that this difficulty could recur without warning —it hit the inaugural flight, for example, while it was taxiing, loaded, to the runway for take-off. Put simply, the problem is severe overheating of the: engine that could cause serious damage if not rectified immediately. It stems from the fact that the intakes on each of the Pratt and Whitney engines are very big, gulping in vast amounts of; air to feed a device that is [required to generate 43,5001 b [of thrust. When the air(craft is slowly taxiing to the ; runway x for take-off, each engine is idling at onlj 4 per! (cent of its full power. Under certain crosswind conditions, for example, at turning' points on the taxi-ways, the crosswind effectively blankets [off the flow of air into one !of the engines—so far, it seems to have happened only to the outboard engines—so, that the air-starved compressor in the engine stalls, the fuel mixture is still being burned, and the temperature rises sharply.

Damage Possible Unless spotted and action taken within seconds (and there is a warning light on; [the flight deck), severe; engine damage could result.! The pilot has no alternative ‘but to shut off the engine,: (and go back to the terminal.: Although, like any other; four-engined airliner, the Jumbo can fly and land safely on three engines, if] one should fail in flight, no] pilot wants to take off, especi-!

ally with a fully-laden Jumbo, on three engines, and no-one would expect him to do so. The problem first occurred when the Jumbo was first leaving Kennedy to fly to London on a demonstration tour. At that time, the flight was delayed three hours for an engine change. The same difficulty has occurred twice since then, the most recent time being on the inaugural flight departure, again from Kennedy, when in bitter weather there were crosswinds of up to 30 to 40 knots sweeping across the airfield. The problem is worrying. Passengers do not like aeroplanes with snag-ridden engines; and airlines do not like losing money through such problems. Work is under way to try to fix it. One solution might be to fit special vanes in the engine air. intakes to deflect crosswinds. Another might be procedural —allowing the Jumbo to taxi much faster along cleared taxi-ways to the runway threshold, so as to keep the engines running at a higher speed. Another might be to toughen the brakes so that while waiting at junctions on taxi-ways the engines could be run-up harder, for it seems that the problem dies away when more power is put on, the suction effect

of the engines countering the crosswind component An answer must be found and not only by Pratt and Whitney. All the large engine companies at work on the high - thrust, large - intake engines will be watching to see how Pratt and Whitney copes. Beyond the aircraft itself lie the operational problems that are only now being experienced, although in all fairness it must be stressed that they have been raised in the past on a number of occasions. 10 Miles Airspace One of the most significant is the ruling, to be implemented both in the United States and in Britain, and probably in other countries too, that no other aircraft should be less than ten miles! behind a Jumbo while it is] landing or less than four minutes behind it during take-off. On approach, there! must be a “height gap” of [ 2000 feet between a Jumbo] and other aircraft. This is be- [ cause the Jumbo, with its] great bulk and four powerful: engines, leaves a wake of disturbed air that could flip over, a light aircraft, and give a big one a very bumpy ride. These are interim measures that may be relaxed in the light of further operational experience. At Heathrow, they are not expected initially to cause too much difficulty in scheduling arrivals and departures, since there is only one Jumbo in and one out daily at present. Even by the end of this year, there will have been only 3500 Jumbo movements at the airport, representing 5 per cent! of all long-haul aircraft move-i ments there. The problem will get progressively more difficult thereafter, however, as more

and more Jumbos come on to the routes. By 1972, there] 'will be 14,000 Jumbo move-

i(ments a year at Heathrow or 1(25 per cent of total long-haul ([aircraft movements and t rising fast. By then there 'may be cause to divert more traffic to Gatwick, south of ((London, and to revise the r]‘‘stacking” and “sequencing” ‘[of aircraft into the airport. ' The problems of timing arri- > vals and departures will fall • on the airlines themselves to 5 solve through their Airlines ' Scheduling Committee, in the light of conditions laid down ’ by the British Airports Auth'[ority and the National Air j [Traffic Control Services at ][the time. ! Passenger Handling ’] So far as passenger handfiling is concerned, the Air’[ports Authority is encour'[aged by the success of its j interim measures, put into -(operation last week. These ’(will be progressively replaced jfrom this spring by the new ’[long-haul permanent buildrings, now nearing completion, ; including the special aircraft ;! stands, passenger lounges and ’ 900-foot long pier with its ([moving “walkway.” Through- ■ out the world, some of the [more enlightened airport ■authorities are sweating to ‘ get Jumbo jet handling ; arrangements completed. But ;at some airports, little ' account seems to have been taken of the problem to come.

To some extent, the problems are likely to continue 1 for some time, until the I Jumbo has effectively been 1 “run in.” The problem for 'Pan American in the next (few weeks is one of main- ■ taining public confidence in ■ the Jumbo. Passengers may not necessarily be afraid of ’Jit, but no-one is going to ■book himself on it if he can- ■ not be sure that it will take- ' off and get him to his des- ' tination on time.

j Bowl Of Publicity • Boeing, Pratt and Whitney, [and Pan American are all I living and suffering in the 1 goldfish-bowl of world pub- ’ licity they have created for ‘[themselves by building, buyfjing and flying the world’s ■lbiggest commercial jet-liner. ‘(While the thing goes well, the publicity is fine, but ; when things go wrong, it can 1 be one of the most expensive J and painful forms of misery ' It may be a new experience ’ for them, but in Britain we ’ know all about it. 8.0.A.C. ■ suffered with the original • Comet jet, and then with the ’ Britannia airliner; Cunard [ suffered with the Q.E.-2. 1 What is important to remem- ] ber about the Jumbo is that • 28 airlines have ordered 186 of them, and the financial 1 stakes are colossal—over 1 £2ooom in orders alone. The problems may be ■ tough, but they will be fixed 1 in time, and the Jumbo will I then go on to become one ’ of the world’s great aero--1 planes. The contribution it 1 will make to world air travel : in the 1970 s and 1980 s can 1 hardly be gauged at this ■ stage, but many a race has ■ been won despite a stumbling ’ start.