THE NATURE OF THE MENACE POSED TO INTERNATIONAL AVIATION BY HIJACKING IS ANALYZED; AND THE SECURITY MEASURES UNDERTAKEN AT AIRPORTS AND ON BOARD AIRCRAFT ARE DEEMED INADEQUATE. IT IS ALSO THAT GOVERNMENTS AGREE TO PROSECUTE ALL HIJACKERS AND TO ACT IN CONCERT TO INSURE THAT THIS PRINCIPLE IS OBSERVED BY ALL STATES. THE LEGAL BASIS IS EXPLORED FOR A DRAFT CONVENTION ON SANCTIONS PRESENTED BY THE U.S. ON OCTOBER 9, 1970 TO THE LEGAL COMMITTEE OF THE INTERNATIONAL CIVIL AVIATION ORGANIZATION (ICAO). THE DRAFT SANCTIONS CONVENTION PROVIDES THAT IF A STATE DETAINS AN AIRCRAFT, ITS PASSENGERS OR CREW FOR BLACKMAIL PURPOSES, OR IF A STATE FAILS TO EXTRADITE OR PROSECUTE HIJACKERS OR OTHER PERSONS INVOLVED IN INTERNATIONAL BLACKMAIL CAUSING DAMAGE TO AN AIRCRAFT, OR DEATH AND PHYSICAL INJURY TO PERSONS ON BOARD, OTHER STATES MAY TAKE JOINT ACTION AGAINST SUCH A STATE, INCLUDING THE SUSPENSION OF ALL AIR SERVICES TO AND FROM ITS TERRITORY. THE LEGAL BASIS FOR THE PROPOSED CONVENTION ON SANCTIONS IS IDENTIFIED IN THREE SEPARATE SOURCES: 1) ARTICLE II OF THE TOKYO CONVENTION OF 1963, 2) THE DRAFT CONVENTION ON SANCTIONS FOUND IN ARTICLES 6, 7 AND 8 OF THE DRAFT CONVENTION ON HIJACKING APPROVED BY THE LEGAL COMMITTEE OF THE ICAO AT ITS 17TH SESSION, AND 3) ARTICLES 6, 7 AND 8 OF THE DRAFT CONVENTION ON SABOTAGE AND OTHER ACTS ON AIRCRAFT PREPARED BY THE ICAO LEGAL COMMITTEE IN OCTOBER 1970. THE DECISIONMAKING PROCESS PROPOSED BY THE DRAFT CONVENTION ON SANCTIONS IS DESCRIBED AS A TWO-STEP PROCEDURE REQUIRING DETERMINATION OF DEFAULT IN PROSECUTING OR EXTRADITING A HIJACKER, AND DETERMINATION OF THE NATURE OF JOINT SANCTIONS AGAINST THE DEFAULTING NATION. THE POSSIBILITY OF JOINT IMPOSITION OF SANCTIONS IS VIEWED AS A SENSITIVE AND DIFFICULT POLITICAL QUESTION ON WHICH AGREEMENT MAY NEVERTHELESS PROVE EASIER THAN EXPECTED IN THE EVENT OF A GRAVE HIJACKING CASE--PARTICULARLY IF THE MECHANISMS FOR INTERNATIONAL SANCTIONS ARE ALREADY IN PLACE. FOOTNOTES ARE PROVIDED. (DEG)