AD 98-07-13

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 767-200 and -300 series airplanes, that requires a one-time inspection for worn or broken wire bundles in the ceiling above the main passenger door and repair, if necessary; and relocation of the wire bundles to prevent chafing. This amendment is prompted by a report indicating that the opening of the main passenger door caused the door liner and a ceiling panel to chafe and ultimately break wires installed in this area. The actions specified by this AD are intended to prevent these wires from becoming worn or breaking, which could lead to the failure of several systems, such as the fuel shutoff valves, and may contribute to the inability of the flight crew to stop the flow of fuel to the engines in the event of an engine fire.

Final rule

98-07-13 BOEING: Amendment 39-10433. Docket 97-NM-50-AD.\n \n\tApplicability: Model 767-200 and -300 series airplanes; as listed in Boeing Service Bulletin 767-33-0052, Revision 1, dated December 8, 1994, as revised by Notice of Status Change 767-33-0052 NSC 01, dated May 9, 1996; 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 (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 requestshould include specific proposed actions to address it.\n \n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo prevent wires in the area above the main passenger door from becoming worn or breaking, which could lead to the failure of several systems, such as the fuel shutoff valves, and may contribute to the inability of the flight crew to stop the flow of fuel to the engines in the event of an engine fire, accomplish the following: \n\n\t(a)\tWithin 12 months after the effective date of this AD, conduct a one-time inspection to detect worn or broken wires in the wire bundles installed above the main passenger door, in accordance with Boeing Service Bulletin 767-33-0052, Revision 1, dated December 8, 1994, as revised by Notice of Status Change 767-33-0052 NSC 01, dated May 9, 1996. Prior to further flight, repair any worn or broken wires and relocate the wire bundles inboard of this door, in accordance with the service bulletin. Thereafter, no further action is required by this AD. \n\n\tNOTE 2: Inspection; repair, if necessary; and relocation of the wire bundles accomplished prior to the effective date of this AD in accordance with Boeing Service Bulletin 767-33-0052, dated April 2, 1992, is considered acceptable for compliance with the requirements of paragraph (a) of this AD. \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 Manager, Seattle ACO. \n\n\t(c)\tSpecial flight permits may be issued in accordance with sections 21.197 and 21.199 ofthe 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 Service Bulletin 767-33-0052, Revision 1, dated December 8, 1994; as revised by Notice of Status Change 767-33-0052 NSC 01, dated May 9, 1996. 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 May 7, 1998.

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 767-200 and -300 series airplanes was published in the Federal Register on June 6, 1997 (62 FR 31021). That action proposed to require a one-time inspection for worn or broken wire bundles in the ceiling above the main passenger door and repair, if necessary; and relocation of the wire bundles to prevent chafing. \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. \n\nSupport for the Proposal \n\n\tTwo commenters support the proposed rule. Request to Add New Service Information \n\n\tOne commenter requests including the phrase "as amended by Notice of Status Change 767-33-0052 NSC 01, dated May 9, 1996" in the final rule after each reference to Boeing Service Bulletin 767-33-0052,Revision 1, dated December 8, 1994. This commenter states that the Notice of Status Change (NSC) specifies that a larger wire clamp is required than was specified in Revision 1 of the service bulletin. \n\n\tThe FAA concurs. The FAA has determined that the wire bundle clamp specified in the previously referenced service bulletin may be too small for two of the wire bundles on Model 767-200 and -300 series airplanes. For this reason, the FAA considers that the larger wire clamp specified in the previously referenced NSC will provide operators with the proper size clamp, and has changed the final rule accordingly. \n\nRequest to Change Discussion Section of Proposal \n\n\tOne commenter requests two changes to the wording in the Discussion section of the proposal: \n\n\t1. In the first sentence of the second paragraph, which reads "Because these wires are connected to such safety systems as the fuel shutoff valves for the engines ... ," the commenter requests deleting the word "safety" from "safety system." The commenter states that it is incorrect to identify these systems as "safety systems" because if any of the systems fail, a second failure would be required to cause a safety problem. \n\n\tThe FAA concurs partially. The FAA does not agree that these systems are unrelated to safety. When evaluating the loss of functions that protect the airplane from hazardous events, the FAA assumes the existence of the hazard. In the case of worn or broken wiring to the engine fuel shutoff valve, the FAA considers that the inability of the flight crew to close the shutoff valve, given the existence of an engine fire, is a hazardous condition that warrants mandatory corrective action. The FAA considers that changing "safety systems" to "systems related to airplane or passenger safety" would add clarity to the final rule; however, no change to this final rule is necessary since neither the Discussion section nor the term "safety systems" appear in the final rule.\n \n\t2. In the second sentence of the second paragraph, the commenter states that the following statement should be deleted from the final rule: "Such failure of the fuel shutoff valves, for example, would prevent the flight crew from stopping the flow of fuel to the engines in the event of a fire." The commenter states that this statement is incorrect because "the subject wiring failure will affect only the fire handle electrical path to the fuel shutoff valve." The commenter maintains that the redundant fuel control switch path would be unaffected by this failure and that the valve could be closed in case of an engine fire. \n\n\tThe FAA concurs partially. The FAA does not agree that the valve could be closed in case of an engine fire if the fuel control switch failed; however, the FAA does agree to clarify the wording of the final rule in certain sections. \n\n\tAfter evaluating the design of the engine fuel shutoff valve system of the Model 767 series airplane, the FAA has determined the following. First, although in the event of the subject wiring failure, the fuel shutoff valve could be closed via the engine fuel shutoff valve, the ability to close this valve is dependent on the actuation of the fuel control switch by the flight crew before the engine fire handle is pulled, as specified by the Emergency Procedures section of the Model 767 Airplane Flight Manual. Second, the engine fuel shutoff valve cannot be closed if the fire handle is pulled before the fuel control switch is placed in the "CUTOFF" position. \n\n\tBecause of these findings, the FAA has determined that a procedural deviation, such as pulling the fire handle first, could occur under certain circumstances, which would result in the inability to stop the flow of fuel to an engine fire. Further, the FAA has determined that the final rule should continue to identify the loss of fuel shutoff capability as a possible consequence of the wire chafing condition. \n\n\tThe Discussion section does not appear in the final rule; however, the FAA has changed the wording in the Summary section of this final rule and the section that describes the unsafe condition to address the commenter's concern. In these sections the final rule now reads "Wire bundle damage may contribute to the inability of the flight crew to stop the flow of fuel to the engines in the event of an engine fire" instead of " ... would prevent the flight crew ...." \nConclusion \n\n\tAfter 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 \nCost Impact \n\n\tThere are approximately 403 Model 767-200 and -300 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 142 airplanes of U.S. registry will be affected by this AD. \n\n\tIt will take approximately 1 work hour per airplane to accomplish the required inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection on U.S. operators is estimated to be $8,520, or $60 per airplane. \n\n\tIt will take approximately 57 work hours per airplane to accomplish the required relocation of the wire bundles, at an average labor rate of $60 per work hour. Required parts will cost approximately $200 per airplane. Based on these figures, the cost impact of the required relocation of the wire bundles on U.S. operators is estimated to be $514,040, or $3,620 per airplane. \n\n\tThe cost impact figures discussed above are 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 various levels 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 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: 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: