74-08-04 MCDONNELL DOUGLAS: Amendment 39-1811 as amended by Amendment 39-2013, 39-2112, and 39-2399 is further amended by Amendment 39-2443. Applies to all McDonnell-Douglas DC-10 series airplanes. \n\n\tCompliance required as indicated: \n\n\tTo prevent possible in-flight depressurization of the airplane that might result from the opening of an improperly secured cargo door, accomplish the following: \n\n\t1.\tPrior to further flight, unless already accomplished, perform the modifications and functional checks referenced below as follows: \n\n\t\t(A)\tInstall inspection ports and placards in all cargo doors and perform functional check of door systems and operation in accordance with McDonnell-Douglas Alert Service Bulletin A52-35 dated June 19, 1972, or later FAA-approved revisions. \t \n\n\t\t(B)\tModify all cargo door latch actuator wiring in accordance with McDonnell-Douglas Service Bulletin 52-27 dated May 30, 1972 or later FAA-approved revisions. \n\n\t\t(C)\tExcept for those aircraft which have been modified in accordance with McDonnell-Douglas Service Bulletin 52-49 dated October 25, 1973, or later FAA-approved revisions, replace the strike plate and adjust the switches on all forward, center, and aft cargo doors and install a support and plate on the aft cargo door in accordance with McDonnell-Douglas Service Bulletin 52-37 dated July 3, 1972, or later FAA-approved revisions. \n\n\t2.\tPrior to each flight a qualified person will: \n\n\t\tA.\tCheck each cargo door that has been opened since last checked, for proper security as follows: \n\n\t\t\t(i)\tEnsure that the cargo restraint curtain, if installed, is in proper position. \n\n\t\t\t(ii)\tEnsure that no foreign matter is in the exposed door locking mechanisms. \n\n\t\t\t(iii)\tEnsure that locking mechanisms are in proper positions. \n\n\t\t\t(iv)\tEnsure proper locking pin placement by visual check through inspection ports; \n\n\t\tB.\tCheck each cargo door known not to have been opened since last checked per paragraph 2(A), above,(i)\tEnsure that locking mechanisms are in proper positions. \n\n\t\t\t(ii)\tEnsure proper locking pin placement by visual check through inspection ports; and \n\n\t\tC.\tEnsure all cargo door warning lights are extinguished prior to taxi, except as provided in paragraph 12, below. \n\n\t\tD.\tCommunicate to the flight crew, prior to taxi, that the cargo doors have been checked, closed and locked. \n\n\t\tE.\tDefinitions. For the purposes of this paragraph, a qualified person is defined as an individual who has received special training on cargo door latching, and, as listed below, shall be: \n\n\t\t\t(i)\tMechanics at stations where such personnel are stationed and available. \n\n\t\t\t(ii)\tFlight crew member at off-line stations where no other qualified persons are available. \n\n\t\t\t(iii)\tRamp supervisor at line stations where no mechanical personnel are stationed or available. \n\n\t3.\tIf any abnormality in pressurization of the airplane is observed during the initial phases of pressurization, initiate descent and depressurization of the airplane and land at the nearest suitable airport. \n\n\t4.\tNotwithstanding the above, at least one flight crew member for each airplane operation must be indoctrinated in accordance with the FAA approved cargo door training programs for the individual airline or operator. \n\n\t5.\tSpecial flight permits may be issued per FAR 21.197 and 21.199 to operate airplanes to a base to perform the maintenance, modifications or repairs required by this AD. \n\n\t6.\tWithin the next 30 days after the effective date of this AD accomplish the cargo door warning system wiring changes in accordance with McDonnell-Douglas Service Bulletins 52-43 dated October 5, 1972, and 52-44, Revision 1, dated August 14, 1973, or later FAA-approved revisions. \n\n\t7.\tOn or before July 1, 1974, accomplish the cargo door latching mechanism and warning system rework in accordance with McDonnell-Douglas Service Bulletin 52-49, Revision 1, dated March 15, 1974, or later FAA-approved revisions. \n\n\t8.\tOn or before July 1, 1974, install cargo door limit switch covers in accordance with McDonnell-Douglas Service Bulletin 52-54 revision 1, dated April 14, 1973, or later FAA-approved revisions. \n\n\t9.\tIn lieu of compliance with the provisions of any of the above requirements, operators may comply with requirements approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\tNote: Simultaneous with the issuance of the AD, principal air carrier operations inspectors assigned to U.S. DC-10 operators will initiate action to amend the approved air carrier training programs to assure that required flight crewmembers are thoroughly familiar with, and indoctrinated in, the operation of locking cargo doors including: \n\n\t\tA.\tObservation of operation of locking mechanism from the interior. \n\n\t\tB.\tMethod of visual check to ensure engagement of locking pins through exterior inspection ports and related mechanism. \n\n\t10.\tUpon completion of either Douglas Service Bulletin 52-109 dated September 10, 1974, or later FAA-approved revisions, or the production change (Ref. Functional Check TXA 7002(L)) or later FAA-approved revisions, or an equivalent installation approved by the Chief, Aircraft Engineering Division, FAA Western Region, on all DC-10 airplanes of an operators fleet, the special checks required in paragraph 2, above, are no longer required. \n\n\t11.\tWithin the next 6000 hours' time in service, after the effective date of this Amendment 39-2112 to AD 74-08-04, unless already accomplished, modify the existing snap switch cargo door warning systems and install new proximity switch cargo door warning systems in accordance with McDonnell Douglas Service Bulletin 52-109, Revision 1, dated December 12, 1974, or later FAA-approved revisions, or equivalent modifications approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\n\t12.\tAircraft which have been modified in accordance with paragraph 11, above, may be operatedwith one warning light (System A or System B) per door inoperative provided: \n\n\t\t(a)\tThe unaffected system test is satisfactory and indicates that the door is closed and locked; and \n\n\t\t(b)\tThe procedure specified by paragraph 2 of this AD is accomplished for the affected cargo door(s); and \n\n\t\t(c)\tThe aircraft is not dispatched from a station where repairs or replacements on the inoperative warning system can be made. \n\n\tAmendment 39-1811 was effective upon publication in the Federal Register as to all persons except those persons to whom certain provisions of this amendment were made immediately effective by the telegrams dated March 7, 1974 and March 22, 1974, and the provisions of this amendment not included in those telegrams are effective as to those persons upon publication of this amendment in the Federal Register. \n\n\tNOTE: Amendment 39-2013 to AD 74-08-04 does not relieve the operator from ensuring, by appropriate procedures, that the cargo door is properly secured. \n\n\tAmendment 39-2013 became effective November 21, 1974. \n\n\tAmendment 39-2112 became effective April 4, 1975. \n\n\tAmendment 39-2399 became effective October 31, 1975. \n\n\tThis Amendment 39-2443 becomes effective December 1, 1975.