AD 86-01-51 R1

86-01-51 R1 BOEING: Amendment 39-5269. Applies to all Model 747 series airplanes equipped with General Electric CF6 engines, certificated in any category. To prevent accumulation of flammable fluid in the engine strut, which constitutes a fire hazard, accomplish the following, unless already accomplished:

1. Within the next 72 hours time-in-service, inspect and, if necessary, clear the engine strut drains in accordance with the procedures specified in Chapter 71-71-00 of Boeing Maintenance Manual for the Boeing Model 747 airplanes equipped with General Electric CF6 engines. Repeat these inspections at intervals not to exceed 1,000 hours time-in-service. Report results of inspections to FAA, Northwest Mountain Region, Seattle Aircraft Certification Office, Propulsion Branch, ATTN: Kanji Patel, ANM-140S, 17900 Pacific Highway South, C-68966, Seattle, Washington 98168.

2. The repetitive inspections required by paragraph 1., above, may be terminated upon the accomplishment of the following:

A. For Group I and II airplanes defined in Boeing Service Bulletin 747-71-2146, dated November 24, 1978, accomplish the replacement of the inboard and outboard pylon drain lines only, as shown in Figures 2 and 3, respectively, of that service bulletin or later FAA-approved revisions.

NOTE: The portion of this service bulletin pertaining to "Strut Pylon Drain Line Engine Tube Replacement," Figure 1, has been superseded by Boeing Service Bulletin 747-71-2155, Revision 3, dated September 28, 1984.

B. For Group I airplanes, as defined in Boeing Service Bulletin 747-71-2155, Revision 3, dated September 28, 1984, accomplish replacement of the engine strut aft drain and incorporate the bracket/heat shield, in accordance with Work Package I described in that service bulletin, or later FAA-approved revisions; and install forward drain fitting, drain tube, and fluid dam in accordance with Work Package II described in that same service bulletin, or later FAA-approved revisions.

C. For Group II airplanes, as defined in Boeing Service Bulletin 747-75-2155, Revision 3, dated September 28, 1984, install forward drain fitting, drain tube, and fluid dam in accordance with Work Package II described in that service bulletin, or later FAA-approved revisions.

D. For Group III airplanes, as defined in Boeing Service Bulletin 747-75-2155, Revision 3, dated September 28, 1984, accomplish replacement of the engine strut aft drain and incorporate the bracket/heat shield, in accordance with Work Package I described in that service bulletin, or later FAA-approved revisions.

E. For Group I, II, and IV airplanes, as defined in Boeing Service Bulletin 747-75- 2155, Revision 3, dated September 28, 1984, accomplish Work Package III, in accordance with that service bulletin, or later FAA-approved revisions, if the thrust reverser follow-up cable support bracket is found to interfere with the fluid dam.

3. Alternate means of compliance which provide an acceptable level of safety may be used when approved by the Manager, Seattle Aircraft Certification Office, FAA Northwest Mountain Region.

4. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of the inspections and, if necessary, cleaning of the engine strut drain lines.

All persons affected by this directive who have not already received the appropriate service documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA Northwest Mountain Region, 17900 Pacific Highway South, Seattle, Washington, or the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington.

This amendment becomes effective April 18, 1986, as to all persons, except those persons to whom it was made immediately effective by telegraphic AD T86-01-51, issued on January 9, 1986.