Daily Rules, Proposed Rules, and Notices of the Federal Government
For service information identified in this proposed 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; e-mail
You may examine the AD docket on the Internet at
We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the
We will post all comments we receive, without change, to
We have been notified that leaking fuel from the wing leading edge area at the inboard end of the number 5 leading edge slat was discovered during a post-flight inspection on a Model 737 airplane with a fuel quantity of over 2,500 lbs. Subsequent investigation found that the leak occurred in an area of the front spar that does not have a proper drain path and appears to have been caused by a loose retaining nut of the slat track down stop. This led to the fuel draining onto the engine exhaust nozzle. This condition, if not corrected, could result in flammable fluids accumulating in the wing leading edge and draining inboard and onto the engine exhaust nozzle, which could result in a fire.
We have reviewed Boeing Special Attention Service Bulletin 737-57-1293, dated November 13, 2008 (“the service bulletin”). The service bulletin describes procedures for modifying the fluid drain path in the wing leading edge area, forward of the wing front spar.
For Group 1 airplanes, the modification includes applying sealant to the cavities between the inboard slat track ribs and leading edge lower panels at certain slat stations in the left and right wings; installing a flame arrestor tube through the vapor barrier rib at the outboard leading edge strakelet box to direct fluids to the strut drain system; applying sealant to create a form-in-place gasket at the blowout door located under the strakelet box to prevent fluids from leaking onto the engine exhaust nozzle; replacing the existing seal in the fuel shut-off valve access door with a bulb seal to prevent flammable fluid leakage onto the engine exhaust nozzle; trimming the blowout door hinge; and related investigative and corrective actions if necessary. The related investigative and corrective actions include doing a leak test and reapplying sealant.
For Group 2 airplanes, the modification includes removing the parting agent and sealant at the lower leading edge access panel immediately outboard of the fuel shutoff valve access door in the left and right wings, and installing new parting agent and sealant; and doing related investigative and corrective actions if necessary. The related investigative actions include inspecting the blowout door hinge for trim and doing a leak test. The corrective actions include trimming the blowout door hinge and reapplying sealant.
We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the(se) same type design(s). This proposed AD would require accomplishing the actions specified in the service information described previously.
We estimate that this proposed AD would affect 754 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.
Title 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.
We 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
We determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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.
For the reasons discussed above, I certify this proposed regulation:
1. Is not a “significant regulatory action” under Executive Order 12866,
2. Is not a “significant rule” under the 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.
You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:
1. The authority citation for part 39 continues to read as follows:
49 U.S.C. 106(g), 40113, 44701.
2. The FAA amends § 39.13 by adding the following new AD:
(a) We must receive comments by May 22, 2009.
(c) This AD applies to Boeing Model 737-600, -700, -700C, -800, -900 and -900ER series airplanes, certificated in any category, as identified in Boeing Special Attention Service Bulletin 737-57-1293, dated November 13, 2008.
(d) This AD results from a report received of leaking fuel from the wing leading edge area at the inboard end of the number 5 leading edge slat. We are issuing this AD to prevent flammable fluids from accumulating in the wing leading edge and draining inboard and onto the engine exhaust nozzle, which could result in a fire.
(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
(f) Within 24 months after the effective date of this AD, modify the fluid drain path in the wing leading edge area, forward of the wing front spar, and do all applicable related investigative and corrective actions, by accomplishing all applicable actions specified in the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-57-1293, dated November 13, 2008. Do all applicable related investigative and corrective actions before further flight.
(g)(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. Send information to ATTN: Sam Spitzer, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6510; fax (425) 917-6590.
(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.