AD 91-12-03

91-12-03 BOEING: Amendment 39-7014. Docket 91-NM-100-AD.

Applicability: Model 757, 747-400, and 767 series airplanes; as listed in Boeing Service Bulletins 757-26A0026, 747-26A2180, 767-26A0075, and 767-26-0076, each dated March 28, 1991, and 757-26-0027, Revision 1, dated April 11, 1991; certificated in any category.

Compliance: Required within 30 calendar days after the effective date of this AD, unless previously accomplished.

To prevent reduced or blocked discharge of fire extinguishing agent from the cargo compartment metered system, and to prevent false indications of low pressure in the initial discharge system, accomplish the following:

(a) Determine the part number and serial number of each cargo compartment fire extinguishing agent container by inspection of aircraft records or visual inspection of the containers. If the part number and serial number are listed in Appendix 1 of Pacific Scientific HTL/Kin-Tech Division Alert Service Bulletin 26A1100, Revision 1, dated April 3, 1991, prior to further flight, replace the container with one having a part number and serial number not listed in that Pacific Scientific HTL service bulletin. If the part number and serial number are not listed in that Pacific Scientific HTL service bulletin, no further action is required.

(b) An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate.

NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Seattle ACO.

(c) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD.

The required inspections shall be conducted on those airplanes listed in the "Effectivity" sections of Boeing Service Bulletins 757-26A0026, 747-26A2180, 767-26A0075, and 767-26- 0076, each dated March 28, 1991; and Boeing Service Bulletin 757-26-0027, Revision 1, dated April 11, 1991. Part numbers and serial numbers of the cargo compartment fire extinguishing agent containers installed on the airplane shall be compared against the listing of part numbers and serial numbers of potentially contaminated containers contained in Appendix 1, pages 1 through 15, of Pacific Scientific, HTL/Kin-Tech Division, Alert Service Bulletin 26A1100, Revision 1, dated April 3, 1991. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. Copies may be inspected at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington; or at the Office of the Federal Register, 1100 L Street N.W., Room 8401, Washington, D.C.

This amendment (39-7014, AD 91-12-03) becomes effective on June 19, 1991.