HC Deb 03 June 1960 vol 624 cc1841-62

1.48 p.m.

Mr. A. E. Hunter (Feltham)

We are now switching from the problem of Africa to the problem of noise around London Airport. Both are difficult to solve, but I hope that both will eventually find a solution. I am grateful that this subject has been selected today. My hon. Friend the Member for Hayes and Harlington (Mr. Skeffington) and I have, by Questions, raised this matter on many occasions and we are, therefore, pleased to have the opportunity of a full debate.

My constituency lies around London Airport. Some areas of it are very close to the airport, many houses being only a few hundred yards from the runways. Some housing estates were erected before the airport was constructed, for there was quite a lot of building in the area between 1930 and 1939, and since the airport has been constructed there has also been a considerable increase in houses and in population.

The areas affected by aircraft noise are mainly those close to take-offs and landings, and those in the glide paths of the aircraft when they take off and when they land. Many areas besides mine and that of my hon. Friend the Member for Hayes and Harlington are affected. I should imagine that the area affected stretches from Uxbridge, Longford, Heston, Stanwell, to Twickenham, Isleworth, Brentford, Chiswick and Richmond. So the problem of noise from aircraft is one we must endeavour to solve.

I recognise the importance of civil air transport, and we want Britain to be a leading civil air Power. My hon. Friend and I both support that policy, and we are proud of Britain's air achievements and wish them to be continued, but we feel that a balance must be held between the residential population and expansion of jet flying at night till the noise problem is solved.

Of course, we have complaints of aircraft noise during the day. Indeed, I am informed that last Saturday, when a lawn tennis championship at Surbiton was being televised, a jet airliner well over 2,000 feet high prevented the scorer from being heard. That gives some idea of the degree of the noise, for Surbiton is some miles away from London Airport, and yet an airliner flying at well over 2,000 feet meant that the scorer could not be heard on television.

Up to 1st April this year the Minister did not allow jet aircraft to use London Airport during the night. Then the Minister, after noise test trials, to which I shall refer later, gave permission to B.E.A. to use the Comet 4B. This upset many of my constituents, who were prepared to tolerate noise during the day but expected to be allowed to sleep in peace at night. I have had letters, which the Parliamentary Secretary can see, bearing a large number of signatures from Feltham and protesting against the flying of jet aircraft at night. I ask the Minister to reimpose the ban.

The fear is that the permission to B.E.A. to operate the Comet will open the skies at night to other airlines. As we know, the Scandinavian and Swiss Airlines advertised tourist night flights even before they received the Minister's permission. Now leading national newspapers express the opinion that air travel is expanding so fast that the increase in the next year or so will be so vast that the Minister will be forced to allow all airlines to use London Airport at night.

Now I want to refer to the noise test trials. Quite frankly, many of my constituents are sceptical about them and feel they are a farce. I can give some reasons which I think the Minister should take into consideration. One cannot judge from a noise test trial in March what the noise will be in actual flying conditions in July and August. I think that the hon. Member for Heston and Isleworth (Mr. R. Harris) has made this point before. In July and August there is heavy summer traffic at London Airport.

The noise test trials of the Comet BIV were taken at the beginning of March. Not all the runways were used for the noise test. I think the Minister selected only one or two. The noise test trials in March were made when there were cold winter nights when people's windows were shut. That was when the Minister took the test. What are the conditions in July and August? There are warm summer nights, and windows are open; possibly there are french windows leading on to the garden. Conditions are entirely different. I should like the Minister very much to bear that in mind.

Noise is linked with weight, and these trials are taken with aircraft at a certain weight. Do we know for sure that six, nine or twelve months later the aircraft will be operating at the same weight as it was when the noise test trials were taken? I hope that the Parliamentary Secretary will deal with that point.

Another matter that my hon. Friend the Member for Hayes and Harlington and I have put is that of delayed flights. They have not been subject to noise test trials. Since 1st April when the Minister gave permission we have had an average of two flights per night coming into London Airport—flights by jet airliners; maybe American, maybe Boeings; perhaps other airliners of other lines; and those, obviously, have not been subjected to noise test trials, and because they are delayed it is more than possible they fly in at their usual noise.

During the five years since I became a Member of this House I have urged research into this problem. Clearly, in this modern age, air travel, which we want to go forward, will increase. Air travel is popular with business people and popular for holidays. Therefore, not only in this country but internationally, we have lagged behind in research to find a solution of the problem. In April this year the expansion at London Airport was 30 per cent. up on 1959 figures. I feel that probably in July and August the expansion will be still more. As we progress through the 'sixties it is quite possible that air travel will be twice as much as it is today.

I am certain that hon. Members on both sides of the House who are supporting me today will support me in putting the point to the Minister that, till a solution is found to the noise problem the Minister should not allow jet airliners to use London Airport between 11 o'clock at night and 7 o'clock in the morning. The airlines are all run by very competent people, and the Air Corporations and independent corporations are all linked up. Surely, they can arrange their flights between 7 o'clock in the morning and 11 o'clock at night?

That would give them sixteen hours in which to use the airport. For two-thirds of the day, roughly, they could use the airport.

Is it really necessary for people to fly at night, unless in special circumstances? I feel certain that people would find flying by day much more interesting, and it would mean that the residential population in the areas affected by the noise problem could at least sleep in peace at night.

There must be more research to eliminate aircraft noise. The responsibility rests on aircraft manufacturers, airline operators, and the Minister. I quote a statement from Sir Miles Thomas, former Chairman of B.O.A.C., who said: My personal feeling is that we aircraft operators could well consider injecting a new factor into our forward aircraft specifications and refuse to buy machines that do not conform to strict noise limitation. The aircraft manufacturers must concentrate on strict noise limitation.

Top technicians and scientists should endeavour to solve the problem. Let their research be not into greater speed —the planes are travelling at hundreds of miles an hour already—but into producing less noisy engines. The aircraft operators should also insist that all pilots observe height regulations both immediately after take-off and before landing, unless of course there are special circumstances.

My hon. Friend the Member for Hayes and Harlington and myself admit that the present Minister of Aviation and the Parliamentary Secretary have taken an interest in this problem. I know that the Minister wants to solve it, but words alone will not bring about a solution. Money must be spent and research must be done, and the right hon. Gentleman must be tough with the aircraft manufacturers. The Minister should also endeavour to secure international cooperation, because this problem also involves the Americans, the French and the Russians and others.

An enormous amount of money is being spent in an effort to solve the problems of space travel. Why not attempt to solve first the problems affecting travel immediately above the earth's surface? Space travel no doubt will come about and man will reach the moon, but let us first have aircraft which will allow people to carry out the everyday tasks of life, to sleep peacefully at night and enable children to carry on with their education at school. It would be far better if top scientists concentrated first on these problems. I hope that the Minister will stop flights by jet aircraft between the hours of 11 p.m. and 7 a.m. until a solution of this noise problem is found. I hope that he will do all he can in his Department and in co-operation with aircraft manufacturers and British and other operators in bringing this about.

2.3 p.m.

Mr. Dudley Smith (Brentford and Chiswick)

I wish to intervene only briefly in the debate to support much of what has been said by the hon. Member for Feltham (Mr. Hunter). My constituency is affected by aircraft noise, though admittedly not as much as are Feltham, Hayes and Harlington, and Heston and Isleworth which abut on London Airport. Nevertheless, aircraft noise is a serious problem in my constituency, although we are fortunate enough to live quite a distance away from the Airport. A number of residents suffer quite seriously, particularly in the Grove Park and Chiswick Park wards. Indeed, they are not slow to tell me that the noise seems to get worse every year and that the hours during which it occurs are gradually being extended.

We all know that the nuisance is far worse in the summer months, and there is a domestic complication for the parents of young children who find it difficult enough to get their children to sleep during the light summer evenings without the aggravation of jets coming over at full boost. Hundreds of residents have their sleep disturbed by this noise. One of the first complaints I received after my election as a Member of this House last October was on aircraft noise, and from that time onwards there has been a steady stream of letters.

A letter which I received only yesterday pinpoints the problem for many people. Part of it reads: Very noisy aircraft frequently fly almost direct over this house after midnight and around six o'clock in the morning. Anyone who sleeps lightly is bound to be woken up. I personally find that I frequently only have about four hours sleep at night because of this. Another letter which I gave to my hon. Friend the Parliamentary Secretary and to which he was kind enough to make a comprehensive reply read: I pay heavy rates and rent in order to live in a reasonably nice locality and here everything is ruined by this noise. What it must be like in the constituency of the hon. Member for Feltham I hardly dare think.

Earlier this Session I asked my right hon. Friend the Minister of Aviation to institute a noise test in my constituency. I thank the Parliamentary Secretary for the reply received this morning, which assures me that the work is now in hand and that the results will be carefully considered. Nowadays we have a further complication for prospective house purchasers in the hazard of aircraft noise. If a man is wise he will find out when buying a house whether it is near an airport or the approach or take-off routes to it; and even whether those are as much as ten or 15 miles away. Property depreciates in value because of aircraft noise, just as it does when a main road is suddenly cut past its frontage. This nuisance of aircraft noise is a growing problem, as is shown by the number of Parliamentary Questions on the subject and the unconventional deputations which arrive on the Minister's own doorstep.

According to a Press report yesterday my right hon. Friend has given a warning to airlines and aircraft firms that they have reached the limit of noise that will be allowed on permitted airports. No planes will be allowed to fly here in future if they make more noise than the new big jets. But, the report adds, the engine manufacturers have told the Minister that present engines cannot be silenced much more, even though future engines will make less noise in proportion to their increased power.

I am sure that no one is silly enough to want a ban on or a serious curtailment of jet flying, because more and more it is becoming the medium of travel for the masses, but if there is sufficient official pressure and sufficient co-operation from the aircraft manufacturers and, above all, sufficient research, I am sure that it is not beyond the wit of today's scientists, with all their knowledge, to produce some form of engine silencer which at least could cut down the noise substantially. This subject must be tackled vigorously, and with a considerable degree of priority, if life in some parts of West Middlesex and West London is not eventually to become intolerable.

2.9 p.m.

Mr. Arthur Skeffington (Hayes and Harlington)

The first thing that I hope the Parliamentary Secretary to the Ministry of Aviation will recognise is that this problem is not just a minor constituency grievance and that after we have spoken and made our complaints we shall simply go away thinking that we have all done our duty. Night jet flying is literally a real nightmare for about 50,000 families living round London Airport, and of course a very serious nuisance to anything up to a million more people.

I must remind the Parliamentary Secretary and emphasise to the House that the 50,000 families are quite unprotected by the Minister's conditions for jet take-off, even if those conditions were always observed, which I sometimes think they are not. There are 50,000 families living within the control points beyond which noise is supposed to be reduced. I hope that this will be appreciated by the Minister.

I have had plotted the control points in relation to the main runways and their positions in relation to the residential communities within that area. They in fact form a pit or sort of Dante's Inferno; indeed, many of the residents would say that the poet never imagined torture such as they have to endure night after night.

I emphasise that, whatever the Minister's conditions relating to the control of noise, these people are certainly entirely unprotected from all disturbances made by jet aircraft. If we take the control points in relation to runway No. 1 east and west, we find that the control point distance from the start of the runway east is 2.6 miles and to the west 3.8 miles. There is thus six miles before the noise has to be reduced under the present Ministry conditions. Therefore, people living in Longford, Harmondsworth, Sipson, Harlington and Cranford Cross gets the full blast from the aircraft because they are living alongside the runway. On No. 5 runway to the east the control point is 3.5 miles away and to the west 4.2 miles. People living at Stanwell, East Bedfont, New Bedfont and Harmondsworth get the full blast before there is any question of protection from noise disturbance.

In addition, they also suffer when the aircraft use No. 6 or No. 2 runway and fly directly overhead. They are totally unprotected by the conditions which the Minister has laid down for taking-off conditions for jets. It is quite intolerable that these 50,000 families, apart from having their day spoiled, are prevented from having and are denied their peace and sleep at night. I do not think that we have the right to inflict that upon 50,000 families and hundreds of thousands of others who suffer very seriously from noise further away.

I believe the Parliamentary Secretary knows that this is not a frivolous protest, because he has been there to hear the jets taking off. I understand that he went there during daylight when people are fully awake and there are other noises about, which means that the noise from these jet aircraft is not quite such a shock. I invite him to spend the night in this Dante's Inferno and to experience being wakened by these intolerable noises.

The Daily Express sent a reporter on 25th May to London Airport. I am sure that the hon. Member for Brentford and Chiswick (Mr.D.Smith) will not mind my saying that I make due allowance for journalistic exuberance; but this is what the reporter wrote: At 1.15 in the morning a monster takes hold of my pyjama lapels, jerks me upright out of sweet dreams into nightmare, and throws me back in horror on my pillow. A night jet is taking off from London Airport. The article goes on: By 7 a.m. there are seven cigarette stubs in the ashtray beside my bed and I have read 243 pages of 'The Thousand and One Nights', which my host has thoughtfully placed there for my entertainment. In all, I suppose, I get three-and-a-half hours' sleep."

That is not really an exaggerated picture. If one lives near the airport no doubt one gets a little less shock on being awakened. I know from my own experience at night and what people have told me, that their children are regularly awakened every night by this noise and, once awake, it is extremely difficult to get them to go to sleep again, and by then probably another disturbance occurs.

How serious this may be from a medical point of view, I do not think we know. There has been a tendency to pooh-pooh it. Dr. Wigley made some observations reported by the Medical Officer of Health for Middlesex to a meeting of the Standing Airport Consultative Committee in which he said that he had had the opportunity of being present when the noise level on the very worst spots round London Airport was read on an occasion last summer when readings between 110 and 120 decibels were recorded. He states: I am assured on good authority that noise levels of this intensity will cause permanent deafness but, of course, only a few people are subjected to noise of this volume and that for very short intervals. I am not sure about this last qualification, but we are at the threshold of something that can have direct and must have some indirect physical medical results if this noise goes on for a long time.

There has been a tendency on behalf of some interests to create a different kind of public attitude and different standards to this nuisance than we normally apply in connection with other noises and disturbances. For many years now there have been certain sections of railway lines where whistles may not be sounded, near hospitals and other places at night. The police have powers to take action against motor vehicles and motor cycles that are noisy. There was a successful prosecution at Southend against the rider of a motor cycle which had exceeded 93 decibels, which is considerably less than much jet noise. Though decibel measurement does not reveal the whole intensity of the quality of the noise which is experienced from jets.

I hope that the House will stiffen its attitude to any relaxation of public standards of decent conduct in this matter, because that would seem to me to be subjecting these unfortunate people to a permanent condition of living which no Member of this House would tolerate and which I do not believe is needed on the facts of air travel. What can be done? First, I would ask the Parliamentary Secretary to be far less secretive about this problem. There is a grave failure in public relations between London Airport and the local residents' associations and, to some extent, between the Ministry and the public.

I think that the Minister and the Parliamentary Secretary are sympathetic to the problem. It would be very much better if they told the public all the full facts instead of our having to dig this information out. The South Harlington Residents' Association asked London Airport the number of emergency and standby landings. The information was refused. I had to put down a Parliamentary Question. This revealed that the number was not unduly alarming. It is far better for people to know at once the extent of the problem. Secretiveness creates the worst impression, and it is quite unnecessary. There was no need for Members of Parliament to take up time in putting down unnecessary Questions. This kind of information is freely available in many other airports throughout the world.

Another example was the occasion when the Minister announced that he had given permission, under certain circumstances, for the Comet 4 to fly at night. It was said that it would be limited to one or two flights at night. The residents said that this was nonsense as they were disturbed more often than that. After prolonged probing the reason was the flights which had been delayed coming in and taking off. Again, we had to put down a series of Questions. Why could not the facts have been given at first? We found that in a period of fifty days there were some forty-four delayed flights in and some thirty-three out. That is an average of almost two a day, in addition to the permanent flights. That may not be a very large number, but if people had known exactly what was the position, or what it was likely to be, they would have been more prepared and could feel greater confidence in the information which is given.

I want to say one thing about the noise tests. My hon. Friend the Member for Feltham has referred to a confidential letter from the Minister, giving some data. He was good enough to show me that letter, which I understand is no breach of confidence. I think the letter was a very superficial one. It does not give any details as to how tests were made. It does not say whether there was a head wind or what was the general weather conditions. Further, all the tests appear to have been made from one runway. It appears to have been assumed that the data compiled from the check point or points for one runway could be applied to all the other runways on the aerodrome, but I do not believe they can. It is not right to lead Members of Parliament up the garden, as I believe my hon. Friend was fed up the garden on this occasion.

Why cannot we have the full facts? I have here a 20-page report, prepared by the noise consultants—Bolt, Beranek and Newman—to the Port of New York Authority. It is Report No. 683, Job No. 20,214, and it refers to the takeoff noise characteristics of the Boeing 707–320 jet airliners. It is dated January, 1960. This report was given to all the residents' associations in the vicinity, of which there are 24 and can be freely bought by everyone. It contains details of weather conditions, the runways used, noise characteristics, tests made with different engines, or aircraft operating at different levels of thrust. Why do we hush such matters up? Why does this sort of material have to be put in a confidential letter, which is misleading because it gives the most superficial information? We, as Members of Parliament, are not being treated with the consideration we deserve, and I am certain that the public is not. The hon. Member has not been long in office, but I beg him and the Minister to adopt a different attitude to Members of Parliament and the public.

Finally, there is the extraordinary question of the published timetables. We were told that the Minister had given permission only for jet airliners operated by B.E.A., but pages 34 and 40 of the B.E.A. timetables, starting from June, announce night flights by Swiss airlines and Swedish airlines. They are in print. It is no good the Minister saying that he does not edit the timetable. I do not suggest that he knew about this, but the timetable gives the impression that what we are told in this House is just so much window dressing, and that the decision has already been made. I do not believe that it has been made, but I shall find it difficult to convince my constituents about that when they see the printed timetables. It was a disgraceful incident.

The Minister should be frank about the way in which noise statistics are discussed. Either the Minister does not understand the position, or he is being misled. We were told, and we have told our constituents, that conditions for operating jet airliners were such that they would be no noisier than the noisiest of composite piston-engined aircraft. That may be true if the noise statistics are given in decibels. The noise of a jet airliner is about 90 decibels, but decibels do not convey any idea of the quality of the noise, because they leave out the question of vibration.

I can give a simple illustration. If I move a slate pencil in a certain way across a slate I can produce a noise which is so excruciating that everybody has to cover up his ears. That noise, measured in decibels, would be almost negligible, but the degree of annoyance measured in noys would be quite high. Using noys to compare jet aircraft with piston-engined aircraft one gets a very different picture. It is not true to say that they are no noisier.

I have had a comparison made between jet aircraft and piston-engined aircraft, in terms of both decibels and noys. There is not much difference between the two when measured in decibels, but if measured in noys it can be said, roughly speaking, that at every level, whether in flight, coming down, or in terms of thrust by the engine, the jet aircraft is twice as loud in noys. Therefore the Ministry is not being frank with the public when it pretends that jet aircraft are no noisier.

What do we want the Minister to do? First of all, we want him to be quite firm in stating that there will be no extension of jet flights between the hours of 11 p.m. and 7 a.m. I hope that he will not subscribe to the view put forward by the News Chronicle not very long ago, that if London Airport is to continue as a major air terminal the Government will have to override complaints about noise. I do not believe that the Government need do that.

In the first place we cannot sacrifice the 50,000 families to whom I have referred, and I do not see why we should sacrifice the other 750,000. Secondly I do not believe that the international repercussions will be nearly so great as is suggested. The Port of New York refuses to allow jet airlines to take off between 10 p.m. and 7 a.m. over any built-up area, Oslo will not allow jets in at all. I am not saying that we can go as far as that. We must be prepared to sacrifice the day, but I do not see why we should make the sacrifice at night.

It has been said that if we insist upon a ban other countries will reciprocate. I do not believe that that will be so. I have referred to Oslo. The Zurich Residents' Association is pressing its Government not to have jet flights at night, and many other international airports are imposing similar conditions. I can see no reason why we should not come to some international agreement on the matter. If we sell the pass Vienna and every other city will follow suit automatically.

When air travel is so speedy it cannot make much difference if we sacrifice a few hours of the night when jets may not take off. It is not as if passengers will miss a tide, or arrive a month late in Australia. It makes only a few hours' difference, and it means that 50,000 families will get their normal rest. We have no right to inflict this kind of gross interference upon people's lives and their right to peaceful nights.

This is not a storm in a teacup, and if the Ministry weakens the inhabitants of Harlington, Feltham, Heston and Isle-worth and Brentford and Chiswick will be marching down Whitehall because public indignation in this matter is not a passing phase but something which is deeply felt by many hundreds of thousands of people.

2.27 p.m.

Mr. Reader Harris (Heston and Isleworth)

I want to support what has been said by the hon. Member for Feltham (Mr. Hunter) and the hon. Member for Hayes and Harlington (Mr. Skeffington). I want to make one more appeal to the Minister on the subject of using coastal strips, at any rate for night-flying jet aircraft. A month or two ago, I put down a Question to the Minister on this subject and I got the very curt answer, "No, Sir", meaning that the Minister would not even consider the matter. I hope that I can revive the suggestion, and that the Minister will not put it entirely out of his mind.

I would have thought that if everything said by the hon. Member for Feltham and the hon. Member for Hayes and Harlington is right—as I know it is—the problem would be regarded as desperately acute. If it is necessary to have night flights by jet aircraft it is up to the Government to make some arrangements which do not mean an intolerable disturbance to thousands upon thousands of families living in many boroughs and urban districts around the airport. We are coming to the part of the year when I shall begin to get letters by the dozen, because people cannot sleep on hot nights with their windows open, when aircraft are making a fearful noise—and there is a great deal of noise at night caused by late flights of aircraft.

If other airlines are given permission to make these flights, life will become intolerable even in Heston and Isleworth, which is a mile or two further from London Airport than is Feltham, or Hayes and Harlington. Residents in Brentford and Chiswick will have the same trouble.

I ask the Minister once again to consider if it is possible to use a coastal strip for the use of jet aircraft at night. He has said "No" once. I ask him once again to consider it, because if he will do so I am certain that it will bring a great deal of amelioration, at any rate to people who live in my constituency.

2.30 p.m.

The Parliamentary Secretary to the Ministry of Aviation (Mr. Geoffrey Rippon)

I am very glad that the hon. Members for Feltham (Mr. Hunter) and Hayes and Harlington (Mr. Skeffington) have raised this subject. My right hon. Friend and I appreciate that, as the hon. Members stated, it is not a matter which concerns merely their own constituents. It concerns many people living within a fairly wide radius of London Airport.

I can say to the hon. Member for Feltham that I was at Surbiton watching the tennis tournament all the afternoon, and I did not notice that jet aircraft. However, I do not for that reason dispute much of the truth of what he told the House. This short but useful debate will help us to clarify the position. I welcome the opportunity of assuring the House that my right hon. Friend and myself are acutely aware of the difficulties and annoyance which many people have to face, especially at night.

All hon. Members must recognise that aircraft noise, at any rate in the present state of knowledge, cannot be eliminated. What we are trying to do is to ensure that it is kept within tolerable limits, both by encouraging research efforts to reduce noise at source—I agree with the hon. Member for Feltham that that is, in the last resort, the only satisfactory solution—and, meanwhile, by devising procedure for the operation of aircraft. The limitations which we impose on noise at night, as I hope to explain, are very much more stringent than those imposed by day.

Before dealing specifically with night flying, I hope that the House will bear with me if I say something about our general policy in order to put night operations into their proper perspective. It has been the consistent aim of the Government to ensure, as far as possible, that the noise of jet-propelled aircraft is no more disturbing than that of the heavier piston-engined aircraft over the main built-up areas. I appreciate the point made by the hon. Member for Hayes and Harlington about the people who live very close to the boundaries of London Airport. Subjective tests were made before jet aircraft were allowed to operate into London Airport. They showed that the requirement would be met in the main built-up areas by day if the sound pressure level did not exceed about 97 decibels, as compared with about 105 decibels for piston-engined aircraft.

In fixing that differential, we were fully aware that sound pressure level, as the hon. Member for Hayes and Harlington pointed out, does not by itself take into account the varying degrees of annoyance to the human ear caused by aircraft of different types. As the hon. Member said, this is related to a combination of air pressure and frequency, although some ears are, in any event, more sensitive to sound than others.

The hon. Member for Hayes and Harlington asked me to deal particularly with the measurement of noise, which is the basis from which all the statistics and the consideration of them must start. We have not felt hitherto that any of the other standards proposed, apart from the decibel, was sufficiently well established to justify the official adoption of an alternative unit of measurement, though by maintaining the differential we had it in mind. However, during the past year a great deal more operational experience has been gained and more scientific research carried out, particularly by the National Gas Turbine Establishment and by the Department of Scientific and Industrial Research. I hope that this may to some extent please the hon. Member for Hayes and Harlington, because as a result I can inform the House that it has been decided to adopt "perceived noise" expressed in decibels, or PNdb's, as the most suitable unit at present available, for the relative assessment of annoyance caused by aircraft of different types.

We accordingly introduced on 1st June a revised limitation of 110 perceived noise decibels measured in the main built-up areas under the take-off paths at London Airport to which operators of jet aircraft will be required to adhere by day. This limitation is broadly equivalent to a sound pressure level of 97 decibels.

The hon. Member for Hayes and Harlington said that he would prefer these measurements to be in noys. That is the same measurement as the preceived noise decibel. The only difference is mathematical. Noy is arithmetical. The perceived noise decibel is logarithmic, as is the decibel measurement to which we are now accustomed. In future, anyone who wishes to do so will be able to translate the measurements of perceived noise decibels into noys, if he is so minded. I hope that will encourage the hon. Member for Hayes and Harlington to feel that we are not trying to be secretive about these matters.

Mr. Skeffington

Why not state it in noys?

Mr. Rippon

There is a danger, if we produce large numbers pf twenty-page reports and masses of statistics, that it would be more misleading. The New York authority has decided to cease the publication of its regular statistics, on the ground that they are merely repetitive. They can also be misleading sometimes.

The hon. Member for Hayes and Harlington cannot complain if from time to time we think it right to give information to hon. Members which we cannot give to every member of the public who writes and asks for it. The House is the proper channel of information. We cannot be accused of treating hon. Members in a cavalier fashion if we say that it is very often right that statistics and statements should be made in the House, rather than in answer to correspondence.

The difficulty with all these statistics is that there is an inevitable margin of error. Random turbulance in the air may cause a scatter of measurement of plus or minus one or two decibels. Engine noise at source will vary by one or two decibels. The weather has an effect ߞwhether it is a blue sky or whether there is a great deal of cloud off which the noise will be reflected. Equally, as the hon. Member for Feltham said, it makes a difference whether one is out of doors or indoors and whether the window is open or shut.

That is why we feel that it is important to maintain as far as possible a degree of flexibilty. We do not want to fix upper statistical limits of noise, particularly at night, which will become the normal standard of achievement. For example, short-haul aircraft can do appreciably better than long-haul aircraft, and we shall expect them to do so. The real aim must be to ensure that, where one company achieves a better performance with similar aircraft in comparable conditions, other companies measure up to that standard. There may well be a great deal in what the hon. Member for Feltham said about future aircraft. Companies may be expected to purchase and use those aircraft which do not cause the maximum disturbance to people living in the vicinity of airports.

As regards night flying, the House will appreciate that there never has been a complete ban on night operations by jet aircraft at London Airport. Although until recently no jet aircraft were scheduled to operate between 11 o'clock at night and 7 o'clock in the morning, delayed aircraft have been permitted to land at any time and, in certain circumstances, to take off.

The hon. Member for Hayes and Harlington referred to the Answers given to Questions tabled by himself and his hon. Friend the Member for Feltham. Those Answers showed that only 11 of the 44 take-offs referred to took place after midnight. We must accept that some delays are inevitable, because of weather or mechanical faults.

The real safeguard for the public is that it is obviously in the company's interest, if it can, to keep to its schedules. Delayed departures are, however, subject to a greater degree of control. Permission for delayed departures up to midnight is granted only to those airlines which have shown that their aircraft can achieve a high compliance with our noise arrangements by day. There are, in fact, large numbers of companies which are not cleared for take-off between 11 p.m. and midnight. For departures after midnight, the airlines must demonstrate by noise tests that the delayed services can be operated at noise levels significantly below those by day. The best way of explaining the effect of this limitation would be to say that, apart from scheduled operations, only two companies have permission to take off after midnight.

In regard to scheduled operations, we have now permitted a number of short-haul jet services to be scheduled at night, and here my right hon. Friend has insisted on noise tests on receiving an application by an airline for permission to operate jet services at night. I do not think that it is fair to say that these noise tests, which my right hon. Friend explained to the House the other day, are in any way inadequate. They are carried out by day at representative all-up weights, with measuring points, in the open air, and that is a fair basis on which to determine whether it is reasonable to give permission. These services are not, and will not be, allowed to proceed until we are satisfied that they comply with these noise tests.

Where B.E.A. is concerned, the tests showed ߞand this has been stated in the Houseߞthat the average pressure level of the Comet 4B was 90 decibels, a figure which is exceeded by several of the piston-engined aircraft which regularly operate at night. These are figures achieved by weight penalties and other methods which, in answer to the hon. Member for Feltham will have to be maintained in the future. I am pleased to be able to tell the House that B.E.A. has complied with the figures which we have laid down in the services which it has undertaken so far.

Now I come to the applications by the Scandinavian Airlines and Swissair, who both recently asked for permission to schedule a number of Caravelle services at night. Both airlines intend to use Caravelles with Rolls-Royce Avon Mark 527 engines, fitted with noise suppressors. Here again, as my right hon. Friend told the House recently, noise tests were a precondition to consideration of the applications. There was certainly no decision at the time when the timetables were published. Companies publish timetables at their own risk, and they are sometimes disappointed. That has been the case with the Scottish Sunday services, and while I think that some Scottish Members were disappointed, the pass has not, in fact, been sold.

Both Scandinavian Airlines and Swissair have shown that they can keep their noise down to a level comparable with that achieved by B.E.A. with its Comet 4Bs. I should inform the House that my right hon. Friend has now granted permission for these services to proceed. This will involve ten take-offs and ten landings a week, seven by Swissair and three by S.A.S.

Mr. Hunter

Was the noise test carried out for these two airlines?

Mr. Rippon

Yes. That is the point I am making. I have said that these airlines have shown that they can, by the noise tests on which my right hon. Friend has insisted as a pre-condition of considering their applications, keep noise to a level comparable with that achieved by B.E.A. with Comet 4Bs.

I appreciate the difficulty that arises in determining the number of frequencies, because, as the hon. Member for Hayes and Harlington pointed out, we have to take into account delayed aircraft, and this is a variable factor. At a rough estimate, the figure of ten take-offs at night should not be very wide of the mark. I would not wish to mislead the House, however, into thinking that there will not be any increase. It would be unrealistic to place a complete ban on these operations after 11 p.m., and I am also bound to say to my hon. Friend the Member for Heston and Isleworth (Mr. R. Harris) that I do not think that it is a practicable proposition to try to operate these night operations, or any operations, on coastal strips.

The hon. Member for Hayes and Harlington referred to the position at other airports. Of course, these flights have been permitted in a large number of other airports, including Amsterdam, Brussels, Cologne, Copenhagen, Frankfurt, Hamburg, Madrid, Moscow, Nice, Rome, Vienna and Zurich. In the case of Oslo and Stockholm, which he said were closed to jet operation at night, alternative airports are available and are used under unrestricted terms. New York is perhaps particularly fortunate in that there are two runways which enable take-offs to be made over Jamaica Bay and avoid built-up areas.

All I can do is to assure the House that my right hon. Friend and I will continue to insist that the aircraft weight is so arranged that, in conjunction with the best possible operational procedures, the noise levels in the main built-up areas under the take-off paths are significantly less than they are by day. We shall continue to require noise tests in order to satisfy ourselves of this. It may also be of interest to the House to know that we are working on plans for the extension of monitoring, which was a point made by my hon. Friend the Member for Brentford and Chiswick. We do check the heights of the aircraft to see that there is compliance with this procedure, and we shall continue to do so, and will try to extend as far as possible this monitoring and checking. We are not unaware of the disturbance which may be caused during phases of an aircraft's flight other than immediately after the take-off.

The real difficulty here is that procedures cannot easily be adapted to reduce noise at every stage. That is the difficulty which faces the 50,000 families, to whom the hon. Gentleman referred. I do not know what is the precise number affected, but, quite obviously, those who live round the boundaries of the airport are going to be disturbed by aircraft noise of all kinds by day and night almost as much by conventional as by jet aircraft.

Our only long-term solution is the abatement of noise at the source, and it was with that primary aim in view that my right hon. Friend held what I think will be regarded as an important meeting on Wednesday last, at which the leading members of the aircraft and aero-engine manufacturing firms and of our own and foreign airlines were present. My right hon. Friend took that opportunity to stress the annoyance which was being caused and the disturbance to which hon. Members have referred. He made it perfectly clear that it was there, and that it was incumbent on all concerned to make a combined effort to tackle this problem, and, that where noise limitations were laid down, they must be adhered to.

I think that the response was encouraging. While recognising, as we must, that airlines will have to operate the types of aircraft that now exist, my right hon. Friend stressed—and this perhaps will be the answer to the hon. Member for Feltham—that they and the aircraft manufacturers would have to give increased attention to the limitation of noise when deciding the specifications for future types. In this connection, the aero-engine manufacturers explained the steps which they are taking to reduce the ratio of noise to power in their current designs. This research should enable the manufacturer of the faster, larger, and heavier aircraft, which we must accept for the future, to take place within the existing limits of noise. In the case of smaller jets, we should do better than merely maintain the position as it is today.

I can say that, as the result of the very great efforts of the aircraft and aero-engine manufacturers, pre-flight studies of the DH121 show that it will be appreciably quieter than the Comet 4B. This is an example of the sort of thing that is taking place. Of course, we should recognise that this noise suppression involves penalties in the form of the weight and the economic operation of the aircraft, but I can assure the House that this is being accepted as necessary in the public interest.

In conclusion, it is only fair to emphasise that the airline companies are doing their best to comply with the operational procedures and make them more effective. The House can be sure that we are all determined to do everything we can to limit and to mitigate the effects of aircraft noise to the fullest extent possible in practical terms and consistent with the operation and continued development of one of the world's major international airports.

Mr. Skeffington

Will the hon. Gentleman let hon. Members have full details of the tests made in connection with the Caravelle? The information will be very useful. Will he also take it from me that perceived noise level decibels are not the same as noys?

Mr. Rippon

Perhaps I can write to the hon. Gentleman on both those points and give a fuller explanation.