90-04-08 BOEING: Amendment 39-6507. Docket No. 89-NM-190-AD. \n\n\tApplicability: Model 727 series airplanes, line numbers 048 through 453, certificated in any category. \n\n\tCompliance: Required within the next 600 landings after the effective date of this AD, unless previously accomplished. \n\n\tTo detect cracking and prevent rapid depressurization, accomplish the following: \n\n\tA.\tConduct an eddy current inspection in accordance with the 727 Non-Destructive Testing Manual (NDT), D6-48875, Part 6, 53-30-27, Figure 8; or an ultrasonic inspection in accordance with the 727 NDT Manual, D6-48875, Part 4, 53-30-27, Figure 2; to determine the configuration of the fuselage skins located between stringer (S) 14 and S-19. If the skin has the .020 inch bonded doubler added to the .040 inch skin, conduct the inspection described in paragraph B., below; otherwise, no further action is required. \n\n\tB.\tIf the fuselage skins are determined to have the .040 inch skin with the .020 inch bonded doubler, conduct a one-time eddy current inspection for cracks of the over-lapped skin in accordance with the 727 NDT Manual D6-48875, Part 6, 53-30-27, Figure 9 or 10, near the bottom row of fasteners in the lower skin of the longitudinal lap splices located at S-14L from body station (BS) 440 to BS 720, and at S-14R from BS 440 to BS 540. Prior to further flight, repair any cracks found, in accordance with a method approved by the Manager, Seattle Aircraft Certification Office, FAA, Northwest Mountain Region. \n\n\tC.\tWithin 10 days after completion of the inspections required by paragraph B., above, submit a report of positive findings of cracks on airplanes with the bonded doubler to the Manager, Seattle Aircraft Certification Office, ANM-100S, FAA, Northwest Mountain Region, 17900 Pacific Highway South, C-68966, Seattle, Washington 98168. The report must include the line number of the airplane inspected, the number of cycles, and the size and locations of the cracks. \n\n\tD.An 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, FAA, Northwest Mountain Region. \n\n\tNOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who will either concur or comment and then send it to the Manager, Seattle Aircraft Certification Office. \n\n\tE.\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 documents from the manufacturer may obtain copies upon request to Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124. These documents may be examined at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 17900 Pacific Highway South, Seattle, Washington, or at the Seattle Aircraft Certification Office, 9010 East Marginal Way South, Seattle, Washington.\n \n\tThis amendment (39-6507, AD 90-04-08) becomes effective on March 19, 1990.