80-01-05 R1 PACIFIC SCIENTIFIC COMPANY KIN-TECH DIVISION: Amendment 39-3646 as amended by Amendment 39-3851. Applies to Pacific Scientific Restraint Systems rotary buckles manufactured through 1970. \n\n\tCompliance required within 240 days from January 31, 1980. \n\n\tTo prevent failure to open of the flight crew and attendants' seat belts, accomplish the following: \n\n\ta.\tInspect crew and attendants' restraint systems to determine if a Pacific Scientific rotary buckle is installed. \n\n\tb.\tIf installed, determine if the rotary buckle assembly contains a black body plate assembly as identified in Figure I of this AD. No further action is required per this AD if the rotary buckle assembly includes a black body plate assembly. \n\n\tc.\tFor those restraint systems incorporating Pacific Scientific rotary buckles without a black body plate assembly as specified in Figure I of this AD: \n\n\t\t1.\tSubstitute of any approved restraint system not incorporating the above described rotary buckle; or, \n\n\t\t2.\tReplace the buckle element of the restraint system with a Pacific Scientific buckle element incorporating a black body plate assembly as identified in Figure I of this AD. \n\n\t\tNOTE: Pacific Scientific Service Bulletin 1101550-25-11 Revision "A" dated August 2, 1979 pertains to this subject. \n\n\td.\tAlternative inspections, modifications or other actions which provide an equivalent level of safety may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\tAmendment 39-3646 became effective January 31, 1980. \n\n\tThis Amendment 39-3851 becomes effective on July 10, 1980.