92-16-10 BOEING: Amendment 39-8319. Docket No. 91-NM-143-AD. \n\n\tApplicability: Model 767 airplanes, as listed in Boeing Alert Service Bulletin 767-29A0064, Revision 1, dated October 24, 1991, certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent hydraulic fluid from entering the cabin, accomplish the following: \n\n\t(a)\tWithin 3,000 flight hours after the effective date of this AD, inspect the inboard leading edge slat power drive unit hydraulic pressure tube for clearance from the adjacent pneumatic duct and for signs of chafing, in accordance with Boeing Alert Service Bulletin 767-29A0064, Revision 1, dated October 24, 1991: \n\n\t\t(1)\tIf the clearance is more than 0.25 inch and there are no signs of chafing, no further action is necessary. \n\n\t\t(2)\tIf the clearance is 0.25 inch or less, or if signs of chafing are found on the hydraulic tube, prior to further flight, replace both the hydraulic pressure tube andthe hydraulic return tube, in accordance with the service bulletin. \n\n\t\t(3)\tIf chafing is found on the pneumatic duct, prior to further flight, repair the pneumatic duct in accordance with the service bulletin.\n\n\t(b)\tFor airplanes on which the hydraulic pressure tube has been replaced in accordance with Boeing Alert Service Bulletin 767-29A0064 (original issue), dated June 13, 1991: Within 4,000 flight hours after the effective date of this AD, replace the hydraulic return tube in accordance with Paragraph III.D. of Boeing Alert Service Bulletin 767-29A0064, Revision 1, dated October 24, 1991. \n\n\t(c)\tAn alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. \n\n\tNOTE: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\n\t(d)\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate the airplane to a location where the requirements of this AD can be accomplished. \n\n\t(e)\tThe inspection, repairs, and replacement shall be done in accordance with Boeing Alert Service Bulletin 767-29A0064, Revision 1, dated October 24, 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. \n\n\t(f)\tThis amendment becomes effective on September 28, 1992.