90-23-06: Leading Edge Inspection

90-23-06 BOEING: Amendment 39-6794. Docket No. 90-NM-220-AD. \n\n\tApplicability: Model 757 series airplanes, line number 1 through 158, certificated in any category. \n\n\tCompliance: Required as indicated, unless previously accomplished. \n\n\tTo prevent separation of trailing edge wedges from the airplane, accomplish the following: \n\n\tA.\tFor airplanes line number 001 through 091, prior to the accumulation of 11,000 flight hours, or within the next 10 calendar days after September 21, 1990 (the effective date of telegraphic AD T90-20-51), whichever occurs later, perform a close detailed visual inspection of the trailing edge wedges on all the leading edge slats for delamination and physical damage in accordance with Boeing Alert Service Bulletin 757-57A0038, Revision 2, dated October 10, 1990, or earlier FAA-approved revisions. \n\n\tB.\tFor airplanes line number 092 through 158, prior to the accumulation of 11,000 flight hours, or within the next 10 calendar days of the effective date of this AD, whichever occurs later, perform a close detailed visual inspection of the trailing edge wedges on all the leading edge slats for delamination and physical damage in accordance with Boeing Alert Service Bulletin 757-57A0038, Revision 2, dated October 10, 1990, or earlier FAA-approved revisions. \n\n\tC.\tRepeat the inspections required by paragraphs A. or B. of this AD, as applicable, at intervals not to exceed 300 flight hours. \n\n\tD.\tIf delamination and/or physical damage are found, prior to further flight, repair in accordance with an FAA-approved procedure or replace with new parts. \n\n\tE.\tAn alternate means 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.\n \n\tNOTE: The request should be submitted directly to the Manager, Seattle ACO, and a copy sent to the cognizant FAA Principal Inspector (PI). The PI will then forward comments or concurrence to the Manager, Seattle ACO. \n\n\tF.\tSpecial 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. \n\n\tAll persons affected by this directive who have not already received the appropriate service information from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. This information may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue S.W., Renton, Washington. \n\n\tAirworthiness Directive 90-23-06 supersedes telegraphic AD T90-20-51, issued on September 21, 1990. \n\tThis amendment (39-6794, AD 90-23-06) becomes effective on November 19, 1990.