AD 97-03-04

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 727 and 737 series airplanes, that requires replacing the fuel cap assembly with a new assembly on the inlet fitting at the inside top of the Boeing-designed auxiliary fuel tank(s). This amendment also requires installing certain new placards once the replacement action is accomplished. This amendment is prompted by reports that the fuel cap assembly, due to its design, became loose and allowed fuel to enter the deactivated auxiliary fuel tanks on in-service airplanes. The actions specified by this AD are intended to prevent unwanted fuel transferring to the deactivated auxiliary fuel tanks, due to the problems associated with a loose fuel cap assembly.

Final rule

97-03-04 BOEING: Amendment 39-9910. Docket 95-NM-106-AD. \n\n\tApplicability: Model 727 and 737 airplanes; as listed in Boeing Alert Service Bulletin 727-28A0062, Revision 5, dated May 4, 1995 (for Model 727 series airplanes) and Boeing Alert Service Bulletin 737-28A1032, Revision 2, dated May 4, 1995 (for Model 737 series airplanes); equipped with forward and/or aft Boeing-designed auxiliary fuel tanks that have been deactivated; certificated in any category.\n\n\tNOTE 1: If the forward and/or aft Boeing-designed auxiliary fuel tank(s) on any of the airplanes specified in the applicability provision is currently activated, the requirements of this AD become applicable whenever that auxiliary fuel tank is deactivated. \n\n\tNOTE 2: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been otherwise 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 (b) 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 as indicated, unless accomplished previously. \n\n\tTo prevent the nut of the fuel cap assembly from backing off and the cap from loosening, and subsequently, unwanted fuel transferring to the auxiliary fuel tanks, accomplish the following: \n\n\t(a)\tWithin 6 months after the effective date of this AD, accomplish paragraphs (a)(1) and (a)(2) of this AD, in accordance with Part IV of the Accomplishment Instructions of Boeing Alert Service Bulletin 727-28A0062, Revision 5, dated May 4, 1995(for Model 727 series airplanes); or Boeing Alert Service Bulletin 737-28A1032, Revision 2, dated May 4, 1995 (for Model 737 series airplanes); as applicable. \n\n\t\t(1)\tReplace the fuel cap assembly having part number (P/N) AN929A24 with a new fuel cap assembly having P/N AN929L24 on the inlet fitting at the inside top of the auxiliary fuel tank, in accordance with the applicable service bulletin. And \n\n\t\t(2)\tReplace the INOP placards with new placards, in accordance with the applicable service bulletin. \n\n\t(b)\tAn 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, Transport Airplane Directorate. 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\n\t(c)\tSpecial 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\n\t(d)\tThe actions shall be done in accordance with Boeing Alert Service Bulletin 727- 28A0062, Revision 5, dated May 4, 1995 (for Model 727 series airplanes); or Boeing Alert Service Bulletin 737-28A1032, Revision 2, dated May 4, 1995 (for Model 737 series airplanes); as applicable. 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\n\t(e)\tThis amendment becomes effective on March 10, 1997.

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 727 and 737 series airplanes was published in the Federal Register on June 19, 1996 (61 FR 31061). That action proposed to require replacing the fuel cap assembly with a new assembly on the inlet fitting at the inside top of the auxiliary fuel tank. That action also proposed to require the replacement of currently-installed "INOP" placards with new placards. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. \n\n Due consideration has been given to the comments received. \n\nSupport for the Proposed Rule \n\n\tOne commenter supports the proposal. \n\nRequest to Clarify Applicability of the Proposed Rule \n\n\tOne commenter requests clarification as to what airplanes would be subject to the proposed AD. The commenter points out that, although the applicability statement of the proposal indicates that it is applicable to all Boeing Model 737 series airplanes, the referenced Boeing Alert Service Bulletin 737-28A1032 applies only to Model 737-200 series airplanes. The commenter questions whether the proposed rule would be applicable to all other types of Model 737's that are equipped with forward and/or aft auxiliary fuel tanks? \n\n\tThe FAA concurs that clarification is needed with respect to the applicability of this AD. First, this AD addresses problems associated only with certain Boeing-designed auxiliary fuel tanks. Those fuel tanks are installed only on airplanes specified in the effectivity listing of Boeing Alert Service Bulletin 727-28A0062, Revision 5, dated May 4, 1995 (for Model 727 series airplanes), and Boeing Alert Service Bulletin 737-28A1032, Revision 2, dated May 4, 1995 (for Model 737-200 series airplanes). The final rule has been revised to specify that: \n\n\t1. the airplanes subject to the AD arethe ones specified in those Boeing alert service bulletins, and \n\n\t2. the subject auxiliary fuel tanks are designed by Boeing. \n\nRequest for Clarification Regarding Future Applicability of Proposed Rule \n\n\tOne commenter requests clarification as to whether airplanes whose auxiliary fuel tanks are not currently deactivated, would be subject to the requirements of the proposed rule if their auxiliary fuel tanks were to be deactivated at some time in the future. \n\n\tThe FAA concurs that clarification is necessary regarding this point. The applicability statement clearly specifies that the AD is applicable to airplanes with deactivated auxiliary fuel tanks. Therefore, the AD is applicable to any airplane whenever its auxiliary fuel tank is deactivated -- now or at any time in the future. The FAA has added a NOTE to the final rule to specify that the requirements of the AD become applicable whenever an auxiliary fuel tank is deactivated on the subject airplanes. \n\nConclusionAfter careful review of the available data, including the comments 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\n Cost Impact \n\n\tThere are approximately 211 Boeing Model 727 series airplanes and 36 Boeing Model 737 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 134 Boeing Model 727 series airplanes and 25 Boeing Model 737 series airplanes of U.S. registry will be affected by this AD.\n\n\tFor Boeing Model 727 series airplanes, the required modification will take approximately 53 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will be supplied by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the AD on U.S. operators of Model 727 series airplanes is estimated to be $426,120, or $3,180 per airplane. \n\n\tFor Boeing Model 737 series airplanes, the required modification will take approximately 18 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will be supplied by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the AD on U.S. operators of Model 737 series airplanes is estimated to be $27,000, or $1,080 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.\n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have substantial direct effects on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the variouslevels of government. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \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 AmendmentAccordingly, 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\n PART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 - (Amended) \n\t2. Section 39.13 is amended by adding the following new airworthiness directive: