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; Internet
You may examine the AD docket on the Internet at
We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the
We will post all comments we receive, without change, to
We reviewed reports of incorrect wire support clamps installed within the left ECS bay, which is a flammable leakage zone. Use of incorrect wire support clamps that are not fully cushioned could allow electrical power wiring to come in contact with the exposed metal of the improper clamp. Power wiring shorts to the exposed metal of the wire support clamp could produce electrical arcing. We are proposing this AD to prevent electrical arcing and a potential ignition source, which in combination with flammable fuel vapors, could result in a fuel tank explosion, and consequent loss of the airplane.
We reviewed Boeing Special Attention Service Bulletin 737-28-1303, dated April 26, 2012. The service information describes procedures for a detailed inspection of certain wire support clamps to identify part number TA0930034-10 wire support clamp and related investigative actions to verify that the flange cushions completely surround the two metal strap sections of the wire support clamp and to detect any possible chafing of the wire bundle within the left side ECS bay, and corrective actions if necessary. Corrective actions include replacing the discrepant clamp with a new or serviceable TA0930034-10 wire support clamp if the part number is incorrect or if the flange cushions do not completely surround the two metal strap sections of the wire support clamp, and repairing or replacing chafed wiring.
We are proposing this AD because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of these same type designs.
This proposed AD would require accomplishing the actions specified in the service information described previously.
We estimate that this proposed AD affects 297 airplanes of U.S. registry.
We estimate the following costs to comply with this proposed AD:
We estimate the following costs to do any necessary replacements that would be required based on the results of the proposed inspection. We have no way of determining the number of aircraft that might need these replacements.
According to the manufacturer, some of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected individuals. We do not control warranty coverage for affected individuals. As a result, we have included all costs in our cost estimate.
We have received no definitive data that would enable us to provide cost estimates for the on-condition repair of chafed or damaged wiring specified in 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:
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.
(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),
(3) Will not affect intrastate aviation in Alaska, and
(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.
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 airworthiness directive (AD):
We must receive comments by October 11, 2012.
This AD applies to The Boeing Company Model 737-600, -700, -800, and -900ER series airplanes; certificated in any category; as identified in Boeing Special Attention Service Bulletin 737-28-1303, dated April 26, 2012.
Joint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 28, Fuel System.
This AD was prompted by incorrect wire support clamps installed within the left environmental cooling systems (ECS) bay, which could allow wiring to come in contact with the exposed metal of the improper clamp. We are issuing this AD to prevent electrical arcing and a potential ignition source, which in combination with flammable fuel vapors could result in a fuel tank explosion, and consequent loss of the airplane.
Comply with this AD within the compliance times specified, unless already done.
Within 60 months after the effective date of this AD, do a detailed inspection for part number TA0930034-10 wire support clamp, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-28-1303, dated April 26, 2012. Do all applicable related investigative and corrective actions before further flight.
As of the effective date of this AD, no person may install a wire support clamp that is not part number (P/N) TA0930034-10 within the left ECS bay of any airplane.
(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:
(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.
(1) For more information about this AD, contact Georgios Roussos, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: 425-917-6482; fax: 425-917-6590; email:
(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; Internet