2012-23148. Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This proposed AD was prompted by a report of chafing damage to a wire bundle that was arcing to hydraulic tubing and caused by insufficient separation between the wire bundle and the hydraulic tubing in the main landing gear (MLG) wheel well. This proposed AD would require an inspection for damage of wire bundles and hydraulic tubing on the right side of the forward bulkhead of the MLG wheel well; installation of new clamps; and corrective actions, as applicable. We are proposing this AD to detect and correct possible damage caused by insufficient separation between the wire bundles and hydraulic tubing to prevent electrical arcing in a flammable fluid leakage zone, which could lead to a wheel well fire.

DATES:

We must receive comments on this proposed AD by November 5, 2012.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

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 [phone], extension 1; fax [phone]; email [e-mail]; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov;​; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (phone: [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Marie Hogestad, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: [phone]; fax: [phone]; email: [e-mail].

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2012-0985; Directorate Identifier 2011-NM-250-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this proposed AD. We will consider all comments received by the closing date and may amend this proposed AD because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

We received a report of a Model 737-800 airplane that was found with the circuit breaker of the #2 engine spar valve open. Maintenance found that a wire had chafed and was arcing to a hydraulic line. The chafing condition was caused by inadequate separation between the wire bundle and the hydraulic line. Boeing inspected additional airplanes in production and found that there was not sufficient separation, based on design requirements, between the wire bundles and adjacent hydraulic tubing at that location. Wire chafing damage and electrical arcing in a flammable fluid leakage zone could lead to a wheel well fire.

Relevant Service Information

We reviewed Boeing Special Attention Service Bulletin 737-29-1113, dated March 23, 2011. That service bulletin describes procedures for a general visual inspection for damage of wire bundles W6128, W7122, W8122, and W8222 and hydraulic tubing part numbers (P/Ns) 272A4451-136 and 272A4451-137, installation of new clamps between the wire bundles and the adjacent hydraulic tubing, and corrective actions as applicable. Corrective actions include repairing damaged wire bundles and replacing or repairing damaged hydraulic tubing.

FAA's Determination

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.

Proposed AD Requirements

This proposed AD would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and the Service Information.”

Differences Between the Proposed AD and the Service Information

The applicability of the proposed AD differs from paragraph 1.A., “Effectivity,” in Boeing Special Attention Service Bulletin 737-29-1113, dated March 23, 2011, to be consistent with the effectivity specified in a correction provided in Boeing Information Notice (IN) 737-29-1113 IN 01, dated May 20, 2011.

Where Boeing Special Attention Service Bulletin 737-29-1113, dated March 23, 2011 specifies a compliance time “after the original issue date of this service bulletin,” this proposed AD would require compliance within the specified compliance time after the effective date of this AD.

Costs of Compliance

We estimate that this proposed AD affects 520 airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Inspection and installation	2 work-hours × $85 per hour = $170	$0	$170	$88,400

We have received no definitive data that would enable us to provide labor cost estimates for the on-condition actions (repairing or replacing of damaged wire bundles and damaged hydraulic tubing) specified in this proposed AD.

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.

Authority for This Rulemaking

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 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.

Regulatory Findings

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),

(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.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by adding the following new airworthiness directive (AD):

The Boeing Company: Docket No. FAA-2012-0985; Directorate Identifier 2011-NM-250-AD.

(a) Comments Due Date

We must receive comments by November 5, 2012.

(b) Affected ADs

None.

(c) Applicability

This AD applies to The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes; certificated in any category; line numbers (L/Ns) 1060 through 3347 excluding L/Ns 3138, 3158, 3169, 3175, 3216, 3224, 3253, 3274, 3290 to 3293 inclusive, and 3295 to 3347 inclusive.

(d) Subject

Joint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 29: Hydraulic Power.

(e) Unsafe Condition

This AD was prompted by a report of chafing damage to a wire bundle that was arcing to hydraulic tubing and caused by insufficient separation between the wire bundle and the hydraulic tubing in the main landing gear (MLG) wheel well. We are issuing this AD to detect and correct possible damage caused by insufficient separation between the wire bundles and hydraulic tubing to prevent electrical arcing in a flammable fluid leakage zone, which could lead to a wheel well fire.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Inspection and Installation

Within 24 months after the effective date of this AD: Do a general visual inspection of hydraulic tubing having part numbers (P/Ns) 272A4451-136 and 272A4451-137, and wire bundles W6128, W7122, W8122, and W8222 for wire chafing or damage, install new clamps in the right MLG wheel well, and do all applicable corrective actions, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-29-1113, dated March 23, 2011. All corrective actions must be done before further flight.

(h) Alternative Methods of Compliance (AMOCs)

(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: [e-mail].

(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.

(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD if it is approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD.

(i) Related Information

(1) For more information about this AD, contact Marie Hogestad, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: [phone]; fax: [phone]; email: [e-mail].

(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 [phone], extension 1; fax [phone]; email [e-mail]; Internet https://www.myboeingfleet.com. You may review copies of the referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

Issued in Renton, Washington, on September 7, 2012.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.