You will recall that at Camp David last November, certain understandings were reached regarding re-scheduling Exercise SKY HAWK.⁹⁴ The terms of this understanding were subsequently embodied in a memorandum which was approved by you and the Prime Minister prior to its formal conveyance to the State Department.⁹⁵ This memorandum read as follows:

“The Canadian Chiefs of Staff Committee and the United States Joint Chiefs of Staff may authorize CINC NORAD to commence preliminary planning for the next exercise forthwith.

“When the broad framework of the exercise has been completed, the Chiefs of Staff of both countries will be briefed on the general outline of the exercise and they in turn will take appropriate action to inform their respective Governments on the nature of the proposed exercise.

“Early in the new year, i.e. April or May, the two Governments will again review the situation and each will then decide whether the exercise is to go forward and will in that event consider the nature of any public announcement to be made.

“If it is decided to proceed, further consultation will take place, presumably some time in July or August, to set a precise date; it being understood that the exercise would take place within the period agreed unless there was a very serious situation which in the view of either Government warranted the cancellation or postponement of the exercise. Such a decision to postpone or cancel could be taken at any time, but would, of course, only be taken at the highest level.” ⁹⁶

In accordance with this understanding CINC NORAD has already undertaken a considerable amount of preliminary planning for the new, large-scale exercise now to be called SKY SHIELD. Furthermore, this planning has reached the stage at which the Chiefs of Staff Committee of both countries have been briefed on the broad framework of the Exercise. The Canadian Chiefs of Staff were briefed yesterday (as were the Joint Chiefs in Washington) and I was present. (As I believe you are aware, it is intended that the Cabinet Defence Committee will be briefed either on Monday afternoon or Tuesday morning next by the Chief of the Air Staff.) It occurred to me, however, that you might also wish to attend a special briefing which will be given to the Minister of Transport and the Minister of National Defence as the Ministers of the two operational Departments which will be held in Mr. Pearke’s office at 9.30 a.m. on Monday morning. In the meantime General Foulkes has given me the attached copy† of an Aide Mémoire on Exercise SKY SHIELD which Mr. Pearkes has given to the Prime Minister. This outlines the general scope of the Exercise. The following additional information may serve to supplement that contained in the Aide Mémoire.

General Scope

Like SKY HAWK, SKY SHIELD is intended as an exercise of the entire NORAD system and to test NORAD’s capability to afford “safe passage” to SAC aircraft while the air defences of North America are under attack. It is planned to take place in September but no firm date has yet been proposed. It will be held between midnight and 7.00 a.m. Eastern Standard Time. In the interests of safety, because virtually unlimited use will be made of electronic counter measures, all civil air traffic — both high level and low level — would be grounded for the period of the Exercise.

Pattern

“Aggressor forces” represented by SAC aircraft will enter the air defence system from the north, south, east and west. Some 284 SAC aircraft will be involved, of which 254 B-47s and B-52s will attempt to penetrate the system. The remaining 30 will act as “safe passage” aircraft. 32 bombers will penetrate the DEW Line, travelling for this purpose only slightly further north than Resolute. 92 bombers will penetrate both coasts of Canada and travel along the Mid-Canada Line. 59 bombers will penetrate the eastern seaboard of the United States, 50 the west coast of the United States, 6 the Gulf coast and 16 Alaska. Two bombers from Thule will penetrate the radar defences in the Foxe Basin area. None of the bombers penetrating the DEW Line or the Alaskan defences will come within range of Soviet radar and the routes they will follow to their assembly points will be the same as those used in regular SAC exercises. It is anticipated that some 3,000 NORAD air defence aircraft will be involved, of which 150 will be either from those based in Canada or flown into Canada during the course of the Exercise.

Communications

The use of ECM will necessÉtate the closing down of most regular channels of communication, either for radar, microwave systems or air traffic radio. There will, however, be no interference to normal radio or television frequencies. Both for safety and for emergency use, two UHF channels will remain open as well as one VHF channel. The maritime bands will not be affected.

Interference with Civil Aircraft

The exact number of civil aircraft which will have to be grounded cannot be determined. The United States authorities calculate that approximately 440 scheduled civil flights in the United States and a large, undetermined number of non-scheduled flights (private aircraft, executive aircraft and non-scheduled cargo and passenger flights) will be affected. The Department of Transport estimate that 51 Canadian scheduled domestic flights, 13 foreign scheduled flights (foreign carriers operating into or out of Canadian airports) and some 30 civiléténerant aircraft will be affected. It has been suggested that should final approval be given the Exercise, the civil carriers would be informed of the need to ground their aircraft prior to the public announcement which would be made well in advance of the Exercise. In this way they would have perhaps some three months’ notice either to re-schedule their flights for the day of the Exercise or cancel them altogether. As it is recognized that the Exercise, if it should go forward, would cause inconvenience to the civil air carriers, NORAD do not plan to re-schedule it for any date other than the date selected. Thus, should the weather of the day not be suitable, the Exercise will be cancelled and not merely postponed. In order to minimize inconvenience, the civil air carriers will be consulted as to the time and date which would be easiest for them.

Public Announcement

A first draft of the proposed public announcement has been reviewed by officials and will be presented to Ministers for their consideration. A copy of this draft as it stands is attached.† When the final text has been approved by Ministers, it will be communicated to the United States Department of Defense through military channels; I assume, however, that in addition you would wish the Embassy in Washington to convey it to the State Department.

N.A. R[OBERTSON]