ALL-UP WEIGHT OF DAKOTA AIRCRAFT

HL Deb 30 January 1947 vol 145 cc305-9

1. A meeting of the Air Safety Board was held at 1500 hours on the 28th January, 1947. In accordance with your instructions, the Board examined the relative considerations applicable to the maximum permissible all-up weight of Dakota aircraft established by Air Registration Board at 28,000 lb. vis-à-vis the American maximum of 25,200 lb. Representatives of British Airline Pilot's Association, Guild of Air Pilots and Air Navigators of the British Empire, British Overseas Airways Corporation, British European Airways Corporation, and Air Marshal Sir Ralph Cochrane, Air Officer Commanding-in-Chief, Transport Command, were invited by the Board and were present.

2. No justification emerged from the discussion for a decrease in the existing Air Registration Board standard, at the present stage of aerodynamic development. It was evident that the British Airline Pilot's Association recommendation to reduce the weight to 26,500 lb. was established on the general premise that by decreasing the all-up weight, an increase in safety would result. The reduction to 26,500 lb. would not eliminate the risk due to engine failure at take-off.

3. The Board, as a result of the information put before it, formed the view that:—

1. (a) All statistical evidence available establishes that an all-up weight of 28,000 lb is acceptable for a Dakota operating under suitable conditions of aerodrome and route and no evidence of accidents directly attributable to this or higher weight was forthcoming.
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2. (b) A reduction in all-up weight introduces new factors, viz.:—
   1. (i) The necessity for shorter stages introducing more take-offs and landings (the chief danger in flying today).
   2. (ii) The diminution in fuel carried, introducing hazards in cases of bad weather.
   3. (iii) The possible disinclination to carry airborne aids to the extent that present unstandard conditions demand.
   A balance of risks must be struck between the small effective gain in safety by reducing the critical period after take-off by a few seconds only, and the increased hazards set out above.
3. (c) The only available performance figures for a Dakota at 28,000 lb. have been calculated theoretically from the American's figures for 25,200 lb. operation. The Board was surprised that no evidence could be found of practical tests carried out in this country before its introduction as a civil type.
4. (d) From the data available to the Board, it is considered that the poor performance of the Dakota on one engine immediately after take-off could only be materially improved by a reduction to an all-up weight of the order of 20,000 lb. to 21,000 lb., when no economical payload could be carried.
5. (e) Maximum permissible all-up weights are directly related to length of runways, altitude of airfields, and geographical features on route. The all-up weights of an aircraft over a mountainous region must be such that the obstruction can be cleared on one engine at maximum permissible cruising revs. It is very satisfactory to note that the Corporations already vary their aircraft loading in respect of these factors. It is doubtful, however, whether Charter Companies do likewise. If not, action should be taken to ensure that they do.
6. (f) A high standard of crew training and an equally high standard of maintenance are relatively more important to safety than a decrease in all-up weights. In this respect, Transport Command completed approximately 250,000 take-offs in 1945 and 157,000 take-offs in 1946 without accident due to engine failure.

4. Having examined the evidence put before it, the Board recommends in respect of the Dakota:

1. (a) The continued application of 28,000 lb. as the Maximum Permissible all-up weight. This weight, of course, implies that the aircraft is being operated from airfields adequate for its class and over routes related to its single engine cruising performance.
2. (b)Initiation by Air Registration Board of an examination of the Maximum Permissible all-up weights which would apply at specific airfields and on particular routes.
3. (c) Trials by Ministry of Supply to examine variations in performance at different all-up weights.

5. Additionally, the Board considers that continuing study of the problem with respect to future aircraft should be diligently progressed. The Viking, Dove and Wayfarer are more particularly concerned.

4.9 p.m.

VISCOUNT CRANBORNE

My Lords, I have no doubt that there are noble Lords who will wish to ask the Minister some questions on this matter, but, before they do so, I should like, if I may, to make a very strong protest that the House was not given any notice that this important statement was going to be made. This is a question of burning interest. There have been shocking accidents lately, I agree not entirely to British aircraft but to aircraft of this type, and the public are deeply concerned about the matter. Your Lordships' House has a number of experts on this particular question who have no opportunity of being here this afternoon. It has always been the custom in the past, when a statement of this importance was to be made, that due notice should be given to the House. I do hope that such a lapse as this will not occur again. It is not in accordance with the traditions of the House, and it gives the House no opportunity of examining these very important and urgent matters.

LORD NATHAN

My Lords, it was because of my recognition of the fact that your Lordships and the country felt profound concern in these matters that I considered it my duty to inform you at the earliest possible moment that I had received the Report, and also to make known the contents of the Report. I received the Report last night and I had to take the opportunity of considering it and its implications in the course of this morning, and I have done so. I have now made this statement so as to inform your Lordships at the earliest possible moment of the fact that the Report has been received, and of the broad recommendations in it. Your Lordships will have observed that I am, with your Lordships' permission, publishing it in full in the Official Report. It is no part of my wish—quite the contrary in fact—to exclude any discussion upon the subject. I am publishing the Report in order that, if it is desired by noble. Lords, arrangements may be made through the usual channels for discussion of the Report whenever may be the most convenient time.

VISCOUNT SWINTON

My Lords, the noble Lord, Lord Nathan, has, I think, entirely misunderstood the point made—and made with great propriety, if I may say so—by the Leader of the Opposition. It was not that the House should not be informed at the earliest opportunity of a decision taken, but that it is the immemorial custom in this House—which no one has been more gracious and consistent in honouring than the present Leader of the House—that, when an important statement is going to be made, the Opposition should be given notice of what is going to be done, at any rate a few minutes before the House assembles. I. myself, owe an apology to the House for not being in my place when the noble Lord began to make this statement. I was in the Chamber, and of course I would have been in my place when this started if the noble Lord had done us the courtesy—which I am sure his noble Leader would have done—of informing us that he was going to make this statement. It is not that we object to the statement being made at the earliest possible opportunity. I hope the noble Lord will in future conform to the regular practice of his Leader in these matters. We will, of course, give very careful consideration to the statement, and afterwards, if it is so desired, no doubt arrangements will be made for a debate.

LORD CALVERLEY

My Lords, with regard to the suggestion by the noble Viscount, Lord Swinton, as to Lord Nathan not knowing the rules of this House, I should have thought that the noble Marquess, Lord Londonderry, when he put down a private notice question, would know that it had to be answered. I should like, from the back Benches, to emphasize that at any rate my noble friend Lord Nathan is not to blame.

LORD BALFOUR OF INCHRYE

My Lords, may I ask the noble Lord one question. He may or may not be able to answer it. It is a supplementary which I think will interest a wide public. As I understand it, Britain is to continue to fly Dakotas at 28,000 lb. Could he tell us why the manufacturers of the Dakota, the American operators and certain Continental operators insist that 25,500 lb. is the safety weight beyond which the aircraft must not be flown? Is it not a fact that Britain has to con- form to that on certain Continental routes, if we wish our Dakotas to go to those countries?

LORD NATHAN

My Lords, I recognize that the noble Lord's question is pertinent to the matters under consideration, but I would suggest to him that it would be wise to wait until he has had an opportunity of studying the Report. It is for that reason that I am causing it to be published.