AD 2001-26-09

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 767-200 series airplanes, that requires a one-time inspection of the water line heater tape where it passes close to the duct assemblies of the air distribution system for the flight compartment to detect damage, and follow-on actions. This amendment also requires eventual replacement of certain duct assemblies or foam insulation on those duct assemblies with new duct assemblies or improved foam insulation. This action is necessary to prevent ignition of foam insulation on the air distribution ducts, which could result in a fire in the airplane. This action is intended to address the identified unsafe condition.

Final rule

2001-26-09 Boeing: Amendment 39-12573. Docket 2000-NM-351-AD. \n\n\tApplicability: Model 767-200 series airplanes, as listed in Boeing Alert Service Bulletin 767-21A0154, dated March 16, 2000; 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 as indicated, unless accomplished previously. \n\n\tTo prevent ignition of foam insulation on the air distribution ducts, which could result in a fire in the airplane, accomplish the following: \n\nInspection and Follow-on Actions \n\n\t(a) Within 18 months after the effective date of this AD: Do a one-time general visual inspection of the water line heater tape where it passes close to the duct assemblies of the air distribution system for the flight compartment to detect damage; including wear, chafing, pinching, discoloration, localized burn marks, etc; per the Accomplishment Instructions of Boeing Alert Service Bulletin 767-21A0154, Revision 1, dated August 9, 2001. \n\n\t\t(1) If no damage is detected, before further flight, measure the clearance between the duct assemblies and the water line heater tape. If clearance is less than 0.25 inch, before further flight, re-route the heater tape per the service bulletin. \n\n\t\t(2) If any damage is detected, before further flight, replace the heater tape with new heater tape, per the service bulletin. When installing the new tape, make sure that clearance between the water line heater tape and the duct assemblies is a minimum of 0.25 inch. \n\n\tNote 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." \n\nReplacement \n\n\t(b) Within 6 years after the effective date of this AD, do the actions specified in paragraph (b)(1) or (b)(2) of this AD, per the Accomplishment Instructions of Boeing Alert Service Bulletin 767-21A0154, Revision 1, dated August 9, 2001. Before further flight after doing the applicable action, do a general visual inspection to make sure that clearance between the water line heater tape and the duct assemblies is a minimum of 0.25 inch. If clearance is less than 0.25 inch, before further flight, re-route the heater tape per the service bulletin. \n\n\t\t(1) Replace the duct assemblies of the air distribution system for the flight compartment (which are located under the main deck) with new duct assemblies having fiberglass insulation; or \n\n\t\t(2) Replace the existing BMS 8-39 foam insulation on the ducts of the air distribution system for the flight compartment (which are located under the main deck) with BMS 8-300 polyimide foam insulation. \n\n\tNote 3: Inspection, replacement and follow-on actions done before the effective date of this AD per Boeing Alert Service Bulletin 767-21A0154, dated March 16, 2000, are considered acceptable for compliance with the applicable actions specified in paragraphs (a) and (b) of this AD. \n\nAlternative Methods of Compliance(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 actions shall be done in accordance with Boeing Alert Service Bulletin 767-21A0154, Revision 1, including Appendix A, dated August 9, 2001. Thisincorporation 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 31, 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 767-200 series airplanes was published in the Federal Register on May 14, 2001 (66 FR 24306). That action proposed to require replacement of certain duct assemblies of the air distribution system for the flight compartment with new duct assemblies with improved insulation, and follow-on actions. \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 comments received. \n\n\tTwo commenters concur with the proposed rule. \n\nChange Paragraph (a) \n\n\tThree commenters ask that paragraph (a) of the proposed rule be changed, as follows: \n\n\tOne commenter states that the proposed AD is similar to AD 2000-26-05, amendment 39-12055 (65 FR 82898, December 29, 2000). That AD requires modification of theenvironmental control system ducts for Model 737, 747, 757, and 767 series airplanes within 6 years after the effective date of the AD. The commenter asks that the compliance time in this proposed AD be changed to allow 18 months for verification of proper clearance between the water line heater tape and the duct assemblies of the air distribution system for the flight compartment, and 6 years for duct insulation replacement, similar to the compliance time allowed by AD 2000-26-05. \n\n\tThe second commenter asks that the compliance time be changed to specify doing the one-time general visual inspection of the water line heater tape, as specified in paragraph (a)(2) of the proposed rule, within 18 months, and then the replacement of the duct assemblies, as specified in paragraph (a)(1) of the proposed rule, within 6 years. The commenter states that, since the burned duct was ignited by an overheated water line heater tape routed too close to a duct assembly, this sequence of actions would ensure an equivalent level of safety, while providing operators the opportunity to replace the duct assemblies at an aircraft's heavy maintenance visit. \n\n\tThe third commenter, Air Transport Association, states that the original equipment manufacturer is developing a service bulletin which will allow replacement of the BMS 8-39 foam insulation on the ducts of the air distribution system for the flight compartment with BMS 8-300 foam. Inclusion of this option in the AD would minimize any need for the replacement of the duct assemblies as the means for installing the new insulation material. The commenter adds that requiring inspection and corrective action to ensure proper clearance between the duct and heater tape within 18 months after the effective date of the AD is prudent. The commenter states that once these actions are satisfactorily completed, an acceptable level of safety would be attained, and safe operations could be continued. The commenter also recommends issuing a supplemental notice of proposed rulemaking to address the revised instructions specified above.\n \n\tWe concur with the commenters. Since the issuance of the proposed rule the FAA has reviewed and approved Boeing Alert Service Bulletin 767-21A0154, Revision 1, dated August 9, 2001. The service bulletin adds an option to replace the existing BMS 8-39 foam insulation on the ducts of the air distribution system for the flight compartment with BMS 8-300 polyimide foam insulation, and recommends inspection of the water line heater tape within 18 months. Therefore, per the revised bulletin and the above comments, the FAA agrees to require either replacement of the duct assemblies or the foam insulation, and to extend the compliance time for that replacement. Revision 1 also has been added as the source of service information for accomplishment of the required actions, and a new Note 3 has been added to give credit for previous accomplishment of certain actions per Boeing Alert Service Bulletin767-21A0154, dated March 16, 2000 (which was listed as the source of service information for accomplishment of the actions specified in the proposed rule). This new requirement gives operators the option of either replacement of the duct assemblies or the foam insulation, and does not add any additional work. Therefore, issuing a supplemental notice of proposed rulemaking is not necessary. \n\n\tParagraph (a) of the final rule has been changed to require an 18-month compliance time for the one-time general visual inspection of the water line heater tape for damage, and follow-on actions; and a new paragraph (b) has been added to expand the compliance time to 6 years for either replacement of the duct assemblies or replacement of the existing BMS 8-39 foam insulation on the ducts with BMS 8-300 polyimide foam insulation. The Summary section in this final rule also has been revised accordingly. \n\nChange Preamble in Proposed Rule \n\n\tOne commenter expands on the language in the Discussion section in the preamble of the proposed rule by stating that the foam insulation was compliant with flammability regulations at the time of airplane delivery. The FAA infers that the commenter wants this information added to the final rule. We acknowledge that certain information in that section could be changed for clarification purposes. However, since that section of the proposed rule does not appear in the final rule, no change to the final rule is necessary in this regard. \n\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 81 airplanes of the affected design in the worldwide fleet. The FAA estimates that 52 airplanes ofU.S. registry will be affected by this AD, that it will take approximately 1 work hour per airplane to do the general visual inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection required by this AD on U.S. operators is estimated to be $3,120, or $60 per airplane. \n\n\tThe replacement of the duct assemblies is one option for compliance with this AD action and will take approximately 2 work hours to accomplish, at an average labor rate of $60 per work hour. Required parts will cost a maximum of $7,285 per airplane. Based on these figures, the cost impact of the replacement of the duct assemblies required by this AD is estimated to be $7,405 per airplane. \n\n\tIn lieu of replacement of the duct assemblies, this AD provides for replacement of the foam insulation on the ducts. It will take approximately 3 work hours to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the replacement of the foam insulation required by this AD is estimated to be $180 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. 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 doesnot 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: