AD 2003-11-25 Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200F, 747-200C, 747-300, 747SR, and 747SP Series Airplanes

Models named: 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200F, 747-200C, 747-300, 747SR, 747SP series. Read the applicability below — it usually turns on serial or part numbers too.

Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200F, 747-200C, 747-300, 747SR, and 747SP series airplanes; line numbers 1 through 644 inclusive; 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 (g) 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 prevent broken H-11 steel bolts, which could result in progressive failure of the remaining bolts and consequent structural damage, rapid depressurization, and loss of control of the airplane, accomplish the following: Initial Inspection (a) Within 18 months after the effective date of this AD: Do a detailed inspection to identify all H-11 steel bolts on the outer chord of the body station (BS) 2360 aft pressure bulkhead between stringers 12L and 12R. Do the inspection by checking the bolt part number stamped on the bolt head, or verifying the bolt is steel by using a magnet, per Boeing Alert Service Bulletin 747-53A2474, dated October 25, 2001. If no H-11 steel bolt is found, no further action is required by this paragraph. If any H-11 steel bolt is found, do the requirements specified in paragraph (c) of this AD. Note 2: For the purposes of this AD, a detailed 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.” Follow-On Inspections/Corrective Actions (b) Within 18 months after doing the inspection required by paragraph (a) of this AD, or within 18 months after the effective date of this AD, whichever is later: Do a detailed inspection to identify all remaining H-11 steel bolts on the entire outer chord of the BS 2360 aft pressure bulkhead, per Boeing Alert Service Bulletin 747-53A2474, dated October 25, 2001. If no H-11 steel bolt is found, no further action is required by this paragraph. If any H-11 steel bolt is found, do the requirements specified in paragraph (c) of this AD. (c) For any H-11 steel bolt found during any inspection required by paragraph (a) or (b) of this AD: Before further flight, do either an ultrasonic inspection or a torque check for cracked or broken bolts, or replace the H-11 steel bolt with an Inconel bolt per Boeing Alert Service Bulletin 747-53A2474, dated October 25, 2001. Replace any cracked or broken bolt with an Inconel bolt before further flight per the service bulletin. Then repeat the inspection of the remaining H-11 steel bolts at intervals not to exceed 18 months until the terminating action required by paragraph (d) of this AD is done. Terminating Action (d) Within 6 years after the effective date of this AD: Replace all H-11 steel bolts on the entire outer chord of the BS 2360 aft pressure bulkhead with Inconel bolts (including visually inspecting the bolt hole for corrosion, oversizing the hole up to 1/32 inch to remove any corrosion, and, after installing an Inconel bolt, coating the bolt with corrosion inhibitor compound), per Boeing Alert Service Bulletin 747-53A2474, dated October 25, 2001. When this paragraph is done, the requirements of this AD are terminated. Exceptions to Service Information (e) Where Boeing Alert Service Bulletin 747-53A2474, dated October 25, 2001, specifies to contact Boeing for appropriate action: Before further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per 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, the approval must specifically reference this AD. Spares (f) As of the effective date of this AD: No person shall install an H-11 steel bolt on the outer chord of the BS 2360 aft pressure bulkhead on any airplane. Alternative Methods of Compliance (g) 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 (h) 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 (i) Unless otherwise provided by this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 747-53A2474, dated October 25, 2001. 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 (j) This amendment becomes effective on July 16, 2003. Issued in Renton, Washington, on May 30, 2003. Ali Bahrami, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 03-14274 Filed 6-10-03; 8:45 am] BILLING CODE 4910-13-P