AD 2001-24-32

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-100, 747-200B, 747-200C, 747-200F, 747SP, and 747SR series airplanes. This AD requires a one-time inspection for chafing of certain wire bundles behind the flight engineer's panel; repairs, if necessary; and a modification to reroute a certain electrical wire bundle to ensure sufficient clearance between that wire bundle and an adjacent flood light support bracket. This action is necessary to prevent chafing of certain electrical wire bundles, which could result in smoke in the cockpit, and uncommanded discharge of fire extinguishing bottles for the No. 4 engine and consequent reduction of the ability to fight a fire in the No. 4 engine. This action is intended to address the identified unsafe condition.

Final rule.

2001-24-32 Boeing: Amendment 39-12549. Docket 2001-NM-220-AD. \n\n\tApplicability: Model 747-100, 747-200B, 747-200C, 747-200F, 747SP, and 747SR series airplanes; line numbers 001 through 310 inclusive; certificated in any category. \n\n\tNote 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 (c) 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. \n\n\tCompliance: Required asindicated, unless accomplished previously. \n\n\tTo prevent chafing of certain electrical wire bundles located behind the flight engineer's panel, which could result in smoke in the cockpit, and uncommanded discharge of fire extinguishing bottles for the No. 4 engine and consequent reduction of the ability to fight a fire in the No. 4 engine, accomplish the following: \n\nOne-Time Inspection and Modification \n\n\t(a) Within 12 months after the effective date of this AD, perform a one-time detailed visual inspection for chafing of wire bundles in the area of the forward upper corner of the P4 flight engineer's panel, outboard of the drip shield. Pay particular attention to wire bundles W528 and W530. \n\n\t\t(1) If any chafing is found, before further flight, repair the chafed wire bundles according to Section 20-10-13 of the Boeing Standard Wiring Practices Manual, and do paragraph (a)(2) of this AD. \n\n\t\t(2) If no chafing is found, or after chafing has been repaired, before further flight, modify the airplane by rerouting electrical wire bundle W530 to ensure sufficient clearance between that wire bundle and an adjacent flood light support bracket and installing a caterpillar grommet on the flood light supports, according to Boeing Alert Service Bulletin 747-25A2407, Revision 1, dated September 23, 1999. \n\n\tNote 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." \n\n\tNote 3: Modifications accomplished prior to the effective date of this AD according to Boeing Service Bulletin 747-25-2407, dated November 18, 1977, are considered acceptable for compliance with paragraph (a)(2) of this AD. However, the detailed visual inspection required by paragraph (a) and any applicable corrective actions required by paragraph (a)(1) of this AD must still be accomplished. \n\nOperator's Equivalent Procedure \n\n\t(b) Where Boeing Alert Service Bulletin 747-25A2407, Revision 1, dated September 23, 1999, specifies that installation of a caterpillar grommet may be accomplished per "your equivalent procedure," the procedures must be accomplished per the applicable chapter of the Boeing 747 Overhaul Manual specified in the service bulletin. \n\nAlternative Methods of Compliance \n\n\t(c) 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 Aircraft Certification Office (ACO), FAA. 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. \n\n\tNote 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\nSpecial Flight Permits \n\n\t(d) 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. \n\nIncorporation by Reference \n\n\t(e) The modification required in paragraph (a)(2) of this AD shall be done in accordance with Boeing Alert Service Bulletin 747-25A2407, Revision 1, dated September 23, 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. \n\nEffective Date \n\n\t(f) This amendment becomes effective on January 16, 2002.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 747-100, 747-200B, 747-200C, 747-200F, 747SP, and 747SR series airplanes was published in the Federal Register on July 23, 2001 (66 FR 38214). That action proposed to require a one-time inspection for chafing of certain wire bundles behind the flight engineer's panel; repairs, if necessary; and a modification to reroute a certain electrical wire bundle to ensure sufficient clearance between that wire bundle and an adjacent flood light support bracket. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the single comment received. \n\nRequest To Exclude Modified Airplanes \n\n\tThe commenter requests that the FAA revise the proposed rule to state that airplanes modified according to the originalissue of Boeing Service Bulletin 747-25-2407, dated November 18, 1977, are not subject to the inspection specified in paragraph (a) of this AD. The commenter notes that it performed the modification in that service bulletin on its fleet of Model 747 series airplanes more than 20 years ago. \n\n\tThe FAA does not concur with the commenter's request. The original issue of the referenced service bulletin does not contain procedures for an inspection for chafing of affected wire bundles, or repair of chafed wire bundles. We find these actions are necessary to ensure that any chafed wire bundles are found and fixed. Therefore, airplanes modified according to the original issue of the service bulletin are still subject to the inspection and any necessary corrective actions described in Revision 1 of the service bulletin, dated September 23, 1999, as required by paragraphs (a) and (a)(1) of this AD. \n\n\tSince the issuance of the proposed AD, however, the FAA has reviewed the modification procedures in the original issue of the service bulletin and determined that those procedures are acceptable for accomplishing the modification required by paragraph (a)(2) of this AD. Therefore, a new Note 3 has been added to this AD (and subsequent notes reordered accordingly) to specify that modifications accomplished prior to the effective date of this AD according to the original issue of the service bulletin are considered acceptable for compliance with paragraph (a)(2) of this AD, but the inspection required by paragraph (a) and any applicable corrective actions required by paragraph (a)(1) of this AD must still be accomplished. \n\nExplanation of Change to Applicability Statement \n\n\tThe applicability statement of the proposed AD specified that the proposed AD would apply to certain airplane models as listed in Boeing Alert Service Bulletin 747-25A2407, Revision 1, dated September 23, 1999. For the convenience of affected operators, we have revised the applicability statement ofthis AD to specify the line numbers of airplanes subject to this AD. \n\nConclusion \n\n\tAfter careful review of the available data, including the comment noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 217 Model 747-100, 747-200B, 747-200C, 747-200F, 747SP, and 747SR series airplanes of the affected design in the worldwide fleet. The FAA estimates that 108 airplanes of U.S. registry will be affected by this AD, that it will take approximately 12 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. The cost of required parts per airplane will be negligible. Based on these figures, the cost impact of this AD on U.S. operators is estimated to be $77,760,or $720 per airplane. \n\n\tThe cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have a substantial direct effect on the States, on the relationship between the national Government and the States, or on the distribution of power and responsibilities among the various levels of government. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. \n\n\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES." \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: