AD 99-22-09 Airworthiness Directives; Boeing Model 747-400 Series Airplanes

Models named: 747-400 series. Read the applicability below — it usually turns on serial or part numbers too.

Model 747-400 series airplanes; as listed in Boeing Alert Service Bulletin 747-53A2430, dated June 10, 1999; 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 prevent a reduction in maximum rudder and elevator surface deflection due to the separation of heat exchangers from the body frame, which could result in reduced controllability of the airplane, accomplish the following: One-Time Inspection (a) Within 400 flight hours or 30 days after the effective date of the AD, whichever occurs earlier, perform a one-time general visual inspection of the crew rest area (CRA) heat exchangers to detect deflection or interference with the flight control cables, in accordance with Boeing Alert Service Bulletin 747-53A2430, dated June 10, 1999. Note 2: For the purposes of this AD, a general visual inspection is defined as: ``A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or drop-light, and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.'' Replacement (b) If no deflection or interference is detected, within 6,000 flight hours after accomplishment of the inspection required by paragraph (a) of this AD, measure the electrical conductivity of the nutplate attachment rivets that attach the heat exchangers to the airframe at station 1920 to determine the rivet material, in accordance with Boeing Alert Service Bulletin 747-53A2430, dated June 10, 1999. Prior to further flight, replace any rivets not made of 2017-T4 aluminum with rivets made of 2017-T4 aluminum, in accordance with the alert service bulletin. (c) If any deflection or interference is detected during the inspection required by paragraph (a) of this AD, prior to further flight, accomplish paragraphs (c)(1) and (c)(2) of this AD. (1) Perform a one-time general visual inspection of the CRA heat exchanger panels, pitot-static tubes, and air distribution ducts in the area of station 1920 to detect damage, in accordance with Boeing Alert Service Bulletin 747-53A2430, dated June 10, 1999. If any damage is detected, prior to further flight, repair in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD. (2) Remove the nutplates and attachment rivets that attach the heat exchangers to the airframe at station 1920, and replace with new nutplates and rivets made of 2017-T4 aluminum, [[Page 57555]] in accordance with Boeing Alert Service Bulletin 747-53A2430, dated June 10, 1999. 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 paragraph (c)(1) of this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 747-53A2430, dated June 10, 1999. 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. (g) This amendment becomes effective on November 10, 1999. Issued in Renton, Washington, on October 15, 1999. D.L. Riggin, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service. [FR Doc. 99-27561 Filed 10-25-99; 8:45 am] BILLING CODE 4910-13-U