AD 92-07-02

92-07-02 BOEING: Amendment 39-8198. Docket No. 91-NM-186-AD. Supersedes AD 90- 08-08, Amendment 39-6572.

Applicability: Model 737-300 series airplanes, listed in Boeing Service Bulletin 737-54- 1028, Revision 1, dated July 11, 1991, certificated in any category.

Compliance: Required as indicated, unless previously accomplished.

To ensure the integrity of the engines' nacelle strut firewall seal, accomplish the following:

(a) For airplanes listed in Boeing Service Bulletin 737-54-1028, dated August 17, 1989: At the next scheduled engine removal, or within 8,000 flight hours after May 14, 1990 (the effective date of AD 90-08-08, Amendment 39-6572), which ever occurs sooner, inspect the engines' nacelle strut door assemblies for proper application of firewall sealant in accordance with Boeing Service Bulletin 737-54-1028, dated August 17, 1989, or Revision 1, dated July 11, 1991. The door assemblies are located between nacelle station 200.00 and 235.00 and attached to the underside of the strut and spar web at approximately nacelle waterline 132.00. If there are gaps, holes, or voids in the firewall sealant, apply sealant prior to further flight, in accordance with the service bulletin.

(b) For airplanes listed in Boeing Service Bulletin 737-54-1028, Revision 1, dated July 11, 1991, that are not subject to paragraph (a) of this AD: At next scheduled engine removal or within 8,000 flight hours after the effective date of this AD, which ever occurs sooner, inspect the engines' nacelle strut door assemblies for proper application of firewall sealant in accordance with Boeing Service Bulletin 737-54-1028, Revision 1, dated July 11, 1991. The door assemblies are located between nacelle station 200.00 and 235.00 and attached to the underside of the strut and spar web at approximately nacelle waterline 132.00. If there are gaps, holes, or voids in the firewall sealant, apply sealant prior to further flight, in accordance with the previously described service bulletin.

(c) 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.

(d) 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.

(e) The inspections shall be done in accordance with Boeing Service Bulletin 737- 54-1028, Revision 1, dated July 11, 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, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington; or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, DC.

(f) This amendment becomes effective April 28, 1992.