80-22-52 MCDONNELL DOUGLAS: Amendment 39-4081. Applies to DC-9-80 series airplanes certificated in all categories with Walter Kidde fire extinguisher systems installed. Compliance required as prescribed in the body of this AD unless already accomplished. To prevent the loss of fire fighting capability due to failure of the fire extinguisher cartridge P/N 876296-01E to discharge the fire extinguishing agent container, accomplish the following: \n\n\tA.\tWithin 24 hours following the effective date of this AD, inspect each cartridge installed in the engine and APU fire extinguishing systems. Identify date stamp and lot number located on the wrench flats of the cartridge. \n\n\t\t1.\tCartridges with date and lot number prior to calendar year 1980 (XX-80) are acceptable and need not be removed. Document inspection in Aircraft Log Book. No further action required. \n\n\t\t2.\tIf either date is calendar year 1980 (XX-80), remove the cartridge and inspect for part number. If the part numberindicated by rubber stamp on the inside shank is "01E," remove from service and dispose of in a proper manner. If the part is indicated as "D" on the shank or P/N 876296 (basic P/N), these cartridges may be reinstalled per maintenance procedures and returned to service. \n\n\tB.\tReplace defective cartridges with cartridges having acceptable part numbers. APU installation may be placarded inoperative if appropriate cartridges are not available. \n\n\tC.\tAll P/Ns 876296-01E should be removed from stock and properly disposed of or returned to vendor. \n\n\tD.\tSpecial flight permits may be issued in accordance with Sections 21.197 and 21.199 of Part 21 of the Federal Aviation Regulations to operate airplanes to a base for the accomplishment of inspections required by this AD. \n\n\tE.\tAlternative means of compliance or other actions which provide an equivalent level of safety may be used when approved by the Chief, Los Angeles Area Aircraft Certification Office, FAA Northwest Region. \n\n\tThis amendment becomes effective April 20, 1981, to all persons, except those to whom it was made immediately effective by telegram dated October 18, 1980.