At its meeting on December 1, 1950, Cabinet Defence Committee considered a request from the U.S. Section of the Permanent Joint Board on Defence to allow U.S. Services to fly over Canadian territory as might be required in order to carry out effective interceptions of unidentified aircraft crossing the border from Canada into the United States. Cabinet Defence Committee agreed to recommend to Cabi­net approval of the U.S. request subject to certain restrictive clauses already accepted by the U.S.A.F. and R.C.A.F. and subject to the extension of reciprocal concessions to Canada by the United States.

At its meeting in Kingston on May 8, the Permanent Joint Board on Defence passed a Recommendation (51/4) on Interceptor Flights. This Recommendation provides for reciprocal privileges and contains the conditions noted by Cabinet Defence Committee on December 1. Some other changes have been incorporated in the Recommendation.

(1) Operations are no longer restricted to the area between 87° West (i.e. Lake Superior) and the Atlantic Coast.

(2) The term "four engine aircraft" has been changed to "multi-engine aircraft" (meaning two or more engines) since it is believed that under certain conditions, twin engine aircraft might now reach the Canada-U.S. border from the U.S.S.R.

(3) The clause "investigating aircraft would not approach closer than 1,000 feet to any single engine or twin engine aircraft" has been changed to "investigating air­craft would not approach closer, in accordance with civil aeronautics authority and Department of Transport standards, than is necessary to establish identification".

It will be noted that the general principles and limitations of the agreement will be translated into operational instructions by a Canadian-U.S. team. The arrange­ments will remain in force until modified by agreement or terminated by either Government.

The Department of Transport has agreed to the Recommendation of the PJBD as it now stands. The Department of Transport expressed its anxiety that every precau­tion should be taken to avoid an attack on a Canadian plane which might inadver­tently cross the U.S. border. In framing the operational instructions, the Canadian­U.S. team is to bear in mind the importance of this point.

It is recommended that Cabinet Defence Committee approve Recommendation 51/4 of the Permanent Joint Board on Defence⁷⁸

A.D.P. HEENEY
for Secretary of State
for External Affairs

⁷⁸ Approuvé par le Comité du Cabinet sur la défense, le 29 mai 1951 et par le Cabinet, le 30 mai1951./Approved by Cabinet Defence Committee, May 29, 1951 and by Cabinet, May 30, 1951.