THE TASK FORCE HAS BUILT ITS ANALYSIS AROUND THE FOLLOWING POINTS: (1) U.S. HIJACKINGS ARE INDIVIDUAL, RANDOM EVENTS; (2) HIJACKING AND SABOTAGE OF AIRCRAFT CAN BE COMBINED INTO ONE INCIDENT, BUT THE HIJACKER AND THE SABOTEUR ARE USUALLY DIFFERENT PEOPLE; AND (3) THE FAA NEITHER PROSECUTES HIJACKERS NOR APPREHENDS THEM--THESE ARE THE RESPONSIBILITY OF THE DEPARTMENT OF JUSTICE. IN KEEPING WITH THE FAA'S INTERESTS, THE TASK FORCE DEVELOPED AN ANTI-HIJACKING SYSTEM THAT RELIES ON BEHAVIORAL CHARACTERISTICS KNOWN TO BE COMMON TO HIJACKERS, AND COMBINES IT WITH A PASSIVE WEAPONS-SCREENING DEVICE. ALTHOUGH DATA COMPILED THROUGH THE USE OF THE SYSTEM SHOWS THAT LESS THAN ONE-HALF OF ONE PERCENT OF KNOWN HIJACKERS BOTH EXHIBIT THE BEHAVIOR AND TRIGGER THE DEVICE, THIS PREBOARDING PROTECTION HAS LED TO THE APPREHENSION OF NONHIJACKING CRIMINALS AND THE DISCARDING OF WEAPONS IN WAITING AREAS, AND ABOVE ALL OFFERS THE EASIEST AND SAFEST MEANS OF CONTROL. THE CRITERIA FOR ONBOARD SYSTEMS ARE THAT THERE BE NO HAZARD TO PASSENGERS, CREW, OR AIRCRAFT; THAT IT BE FAST, EFFECTIVE, FOOL-PROOF, OPTIONAL, AND PROTECTED; AND THAT IT BE UNDER THE COMPLETE CONTROL OF THE CREW. SUCH SYSTEMS ARE OFTEN SEVERELY LIMITED BY HOSTAGE-TAKING TO GAIN ENTRANCE TO THE FLIGHT DECK. GUIDELINES FOR ONBOARD PROTECTION AND PREVENTION ARE BEING RESEARCHED BY THE FAA. HOWEVER, FOR THE TIME BEING, PREBOARDING DEVICES ARE OF GREAT ASSISTANCE. TABLES ILLUSTRATE THE FAA STATISTICAL ANALYSIS OF HIJACKINGS. (MHP)