2012-14245. Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to supersede an existing airworthiness directive (AD) that applies to certain The Boeing Company Model 737-600, -700, -700C, -800, and -900 series airplanes. The existing AD currently requires replacing the drain tube assemblies and support clamps on the aft fairing of the engine struts. Since we issued that AD, we received an additional report of a broken drain tube assembly on the aft fairing of the left engine strut at the clamp support location under the aft fairing compartment, inside the heat shield cavity of the aft fairing. There have also been reports of tube wear at the clamp location on additional airplanes. This proposed AD would require replacing the drain tube assembly of the left and right engine strut aft fairings with a new one which includes an integral support clamp made of nickel alloy 625. This proposed AD would also add airplanes to the applicability. We are proposing this AD to prevent failure of the drain tube assemblies and clamps on the aft fairings of the engine struts. Such failure could allow leaked flammable fluids in the drain systems to discharge onto the heat shields of the aft fairings of the engine struts, which could result in an undetected and uncontrollable fire.

DATES:

We must receive comments on this proposed AD by July 27, 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:

Ansel James, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, Washington 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 proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2012-0591; Directorate Identifier 2012-NM-015-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

On April 8, 2008, we issued AD 2008-08-24, Amendment 39-15478 (73 FR 21242, April 21, 2008), for certain Model 737-600, -700, -700C, -800, and -900 series airplanes. That AD requires replacing the drain tube assemblies and support clamps on the aft fairing of the engine struts. That AD resulted from reports of failure of the drain tube assembly and clamp on the aft fairings of an engine strut. We issued that AD to prevent failure of the drain tube assemblies and clamps on the aft fairings of the engine struts. Failure of the drain tube assemblies could allow leaked flammable fluids in the drain systems to discharge onto the heat shields of the aft fairings of the engine struts, which could result in an undetected and uncontrollable fire.

Actions Since Existing AD Was Issued

AD 2008-08-24, Amendment 39-15478 (73 FR 21242, April 21, 2008), refers to Boeing Special Attention Service Bulletin 737-54-1043, dated May 2, 2007, as the appropriate source of service information for the required actions.

Boeing then issued Special Attention Service Bulletin 737-54-1043, Revision 1, dated October 19, 2009, to replace the drain tube assembly of the engine strut aft fairing and support clamp.

Since we issued AD 2008-08-24, Amendment 39-15478 (73 FR 21242, April 21, 2008), an airplane on which the actions specified in Boeing Special Attention Service Bulletin 737-54-1043, Revision 1, dated October 19, 2009, had been incorporated in production, was reported to have a broken drain tube assembly on the aft fairing of the left engine strut at the clamp support location under the aft fairing compartment, inside the heat shield cavity of the aft fairing (the same location identified in the existing AD). This airplane had accumulated 4,127 total flight cycles and 6,845 total flight hours. There have also been reports of tube wear at the clamp location.

Boeing subsequently issued Special Attention Service Bulletin 737-54-1043, Revision 2, dated November 4, 2011, which describes procedures for replacing the drain tube assembly of the engine strut aft fairing with a new one which includes an integral support clamp made of nickel alloy 625.

Boeing Special Attention Service Bulletin 737-54-1043, Revision 2, dated November 4, 2011, includes Model 737-900ER series airplanes, which were not included in Boeing Special Attention Service Bulletin 737-54-1043, dated May 2, 2007.

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 retain none of the requirements of AD 2008-08-24, Amendment 39-15478 (73 FR 21242, April 21, 2008). This proposed AD would add airplanes to the applicability statement of the existing AD. This proposed AD would also require accomplishing the actions specified in Boeing Special Attention Service Bulletin 737-54-1043, Revision 2, dated November 4, 2011, described in this NPRM.

Costs of Compliance

We estimate that this proposed AD affects 1,098 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
Replacement	14 work-hours × $85 per hour = $1,190	$12,326	$13,516	$14,840,568

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 have 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 that the 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 removing airworthiness directive (AD) 2008-08-24, Amendment 39-15478 (73 FR 21242, April 21, 2008), and adding the following new AD:

The Boeing Company: Docket No. FAA-2012-0591; Directorate Identifier 2012-NM-015-AD.

(a) Comments Due Date

The FAA must receive comments on this AD action by July 27, 2012.

(b) Affected ADs

This AD supersedes AD 2008-08-24, Amendment 39-15478 (73 FR 21242, April 21, 2008).

(c) Applicability

This 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 737-54-1043, Revision 2, dated November 4, 2011.

(d) Subject

Joint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 54, Nacelles/pylons.

(e) Unsafe Condition

This AD was prompted by a report of a broken drain tube assembly on the aft fairing of the left engine strut at the clamp support location under the aft fairing compartment, inside the heat shield cavity of the aft fairing. There have also been reports of tube wear at the clamp location on additional airplanes. We are issuing this AD to prevent failure of the drain tube assemblies and clamps on the aft fairings of the engine struts. Such failure could allow leaked flammable fluids in the drain systems to discharge onto the heat shields of the aft fairings of the engine struts, which could result in an undetected and uncontrollable fire.

(f) Compliance

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

(g) Replacement

Within 60 months after the effective date of this AD, replace the drain tube assemblies and support clamps on the aft fairing of the struts of engines 1 and 2 with new drain tube assemblies and clamps, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-54-1043, Revision 2, dated November 4, 2011.

(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) AMOCs approved previously in accordance with AD 2008-08-24, Amendment 39-15478 (73 FR 21242, April 21, 2008), are not approved as AMOCs with this AD.

(i) Related Information

(1) For more information about this AD, contact Ansel James, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, Washington 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 May 31, 2012.

Michael Kaszycki,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.