AD 2001-14-22 Airworthiness Directives; Boeing Model 747-100 and -200 Series Airplanes

Models named: 747-100, -200 series. Read the applicability below — it usually turns on serial or part numbers too.

Model 747-100 and -200 series airplanes, as listed in Boeing Alert Service Bulletin 747-53A2451, including Appendix A, dated October 5, 2000, certificated in any category. Note 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Required as indicated, unless accomplished previously. To find and fix fatigue cracks of the station 800 frame assembly that could extend and fully sever the frame, which could result in development of skin cracks that could lead to rapid depressurization of the airplane, accomplish the following: Repetitive Inspections (a) Do detailed visual, surface high frequency eddy current (HFEC), and open hole HFEC inspections, as applicable, for cracking of the station 800 frame assembly (including the inner chord strap, angles, and exposed web) between stringers 14 and 18, according to Boeing Alert Service Bulletin 747-53A2451, including Appendix A, dated October 5, 2000. Except as provided by paragraph (b) of this AD, do the inspection at the applicable time specified in Table 1 below, and repeat the inspections thereafter at least every 3,000 flight cycles: Table 1 is as follows: Table 1.— Compliance Times Total flight cycles as of the effective date of this AD Do the inspection in paragraph (a) at this time (1) Fewer than 19,000 Before the accumulation of 19,000 total flight cycles, or within 1,500 flight cycles after the effective date of this AD, whichever comes later. (2) 19,000 or more but 24,250 or fewer Within 1,500 flight cycles or 12 months after the effective date of this AD, whichever comes first. (3) 24,251 or more Within 750 flight cycles or 12 months after the effective date of this AD, whichever comes first. Note 2: For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.” Adjustments to Compliance Time: Cabin Differential Pressure (b) For the purposes of calculating the compliance threshold and repetitive interval for the actions required by paragraph (a) of this AD, the number of flight cycles in which cabin differential pressure is at 2.0 pounds per square inch (psi) or less need not be counted when determining the number of flight cycles that have occurred on the airplane, provided that flight cycles with momentary spikes in cabin differential pressure above 2.0 psi are included as full pressure cycles. For this provision to apply, all cabin pressure records must be maintained for each airplane: NO fleet-averaging of cabin pressure is allowed. Repair (c) If any cracking is detected during any inspection required by paragraph (a) of this AD, before further flight, repair the cracking according to a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or according to data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the approval letter must specifically reference this AD. Alternative Methods of Compliance (d) An 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 ACO. 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. Note 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. Special Flight Permits (e) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. Incorporation by Reference (f) Except as provided by paragraphs (b) and (c) of this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 747-53A2451, including Appendix A, dated October 5, 2000. 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 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. Effective Date (g) This amendment becomes effective on August 30, 2001. Issued in Renton, Washington, on July 12, 2001. Vi L. Lipski, Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 01-18019 Filed 7-25-01; 8:45 am] BILLING CODE 4910-13-P