AD 2011-26-09

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This AD was prompted by reports of excessive in- service wear damage of the thumbnail fairing edge seal, and of the panel rub strip and skin assembly of the fan cowl. This AD requires replacement of the thumbnail fairing edge seals on both sides of the engines with Nitronic 60 stainless steel alloy seals. We are issuing this AD to prevent failure of the fire seal, which could allow a fire in the fan compartment to spread beyond the firewall and reach the flammable fluid leakage zones, resulting in an uncontrolled fire.

Final rule.

Adoption of the Amendment \n\n\n\tAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n0 1. The authority citation for part 39 continues to read as follows: \n\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n\n\nSec. 39.13 (Amended) \n\n0 2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD): \n\n2011-26-09: The Boeing Company: Amendment 39-16899; Docket No. FAA- 2011-0996; Directorate Identifier 2011-NM-068-AD. \n\n(a) Effective Date \n\n\n\tThis AD is effective February 3, 2012. \n\n(b) Affected ADs \n\n\n\tNone. \n\n(c) Applicability \n\n\n\tThis AD applies to The Boeing Company Model 737-600, -700, - 700C, -800, -900, and -900ER series airplanes, certificated in any category, as identified in Boeing Special Attention Service Bulletin 737-54-1046, dated February 16, 2011. \n\n(d) Subject \n\n\n\tJoint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 54: Nacelles/Pylons. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by reports of excessive in-service wear damage of the thumbnail fairing edge seal, and of the panel rub strip and skin assembly of the fan cowl. We are issuing this AD to prevent failure of the fire seal, which could allow a fire in the fan compartment to spread beyond the firewall and reach the flammable fluid leakage zones, resulting in an uncontrolled fire. \n\n(f) Compliance \n\n\n\tComply with this AD within the compliance times specified, unless already done. \n\n(g) Replace the Thumbnail Fairing Edge Seals \n\n\n\tWithin 60 months after the effective date of this AD, replace the thumbnail fairing edge seals, on both the left side and the right side of engine 1 and engine 2, with new Nitronic 60 stainless steel alloy seals, in accordance \n\n((Page 82113)) \n\nwith the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-54-1046, dated February 16, 2011. \n\n(h) Alternative Methods of Compliance (AMOCs) \n\n\n\t(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in the Related Information section of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov. \n\t(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office. \n\n(i) Related Information \n\n\n\tFor more information about this AD, contact Chris Parker, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue SW., Renton, Washington 98057-3356; phone: (425) 917-6496; fax: (425) 917-6590; email: chris.r.parker@faa.gov. \n\n(j) Material Incorporated by Reference \n\n\n\t(1) You must use the following service information to do the actions required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference (IBR) under 5 U.S.C. 552(a) and 1 CFR part 51 of the following service information on the date specified: \n\t(i) Boeing Special Attention Service Bulletin 737-54-1046, dated February 16, 2011. \n\t(2) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P. O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone (206) 544-5000, extension 1; fax (206) 766-5680; email me.boecom@boeing.com; Internet https://www.myboeingfleet.com. \n\t(3) You may review copies of the service information at the FAA, Transport Airplane Directorate, FAA, 1601Lind Avenue SW., Renton, Washington 98057-3356. For information on the availability of this material at the FAA, call (425) 227-1221. \n\t(4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at an NARA facility, call (202) 741-6030, or go to http://www.archives.gov/federal_register/code_of_federal_regulations/ibr_locations.html

Discussion \n\n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM was published in the Federal Register on October 5, 2011 (76 FR 61643). That NPRM proposed to require replacement of the thumbnail fairing edge seals on both sides of the engines with Nitronic 60 stainless steel alloy seals. \n\nComments \n\n\n\tWe gave the public the opportunity to participate in developing this AD. We have considered the comment received. Boeing supports the NPRM (76 FR 61643, October 5, 2011). \n\nConclusion \n\n\n\tWe reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting the AD as proposed. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD affects 989 airplanes of U.S. registry. We estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs ---------------------------------------------------------------------------------------------------------------- \n\tCost per Cost on U.S. \n\tAction Labor cost Parts cost product operators ---------------------------------------------------------------------------------------------------------------- Replace thumbnail faring edge seals. 6 work-hours x $85 per $2,032 $2,542 $2,514,038 \n\thour = $510. ---------------------------------------------------------------------------------------------------------------- \n\nAuthority for This Rulemaking \n\n\n\tTitle 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority. \n\tWe are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: ''General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. \n\nRegulatory Findings \n\n\n\tThis AD will not have federalism implications under Executive Order 13132. This AD 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. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866, \n\t(2) Is not a ''significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), \n\t(3) Will not affect intrastate aviation in Alaska, and \n\t(4) 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. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.