2010-31828. Airworthiness Directives; The Boeing Company Model 737-600, -700, -700C, -800, and -900 Series 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 the products listed above. The existing AD currently requires replacement of the power control relays in the P91 and P92 power distribution panels for the fuel boost and override pumps with new, improved relays having a ground fault interrupter (GFI) feature, or installation and maintenance of universal fault interrupters (UFIs) using a certain supplemental type certificate. Since we issued that AD, we have determined that we need to clarify which relays may be replaced by installation of UFIs. This proposed AD would continue to require the actions of the existing AD and also specify which relays may be replaced by GFIs or UFIs. We are proposing this AD to prevent pump housing burn-through due to electrical arcing, which could create a potential ignition source inside a fuel tank. This condition, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

DATES:

We must receive comments on this proposed AD by February 3, 2011.

ADDRESSES:

You may send comments 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 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]; e-mail [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:

Georgios Roussos, Aerospace Engineer, Systems and Equipment Branch, ANM-130S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

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-2010-1199; Directorate Identifier 2010-NM-225-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 July 27, 2010, we issued AD 2010-17-05, Amendment 39-16395 (75 FR 50859, August 18, 2010), for certain Model 737-600, -700, -700C, -800, and -900 series airplanes. That AD requires replacement of the power control relays in the P91 and P92 power distribution panels for the fuel boost and override pumps with new, improved relays having a ground fault interrupter (GFI) feature, or installation and maintenance of universal fault interrupters (UFIs) using a certain supplemental type certificate. That AD resulted from fuel system reviews conducted by the manufacturer. We issued that AD to prevent pump housing burn-through due to electrical arcing, which could create a potential ignition source inside a fuel tank. This condition, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

Actions Since Existing AD Was Issued

Since we issued AD 2010-17-05, we have determined that there are errors in paragraph (f) of that AD. Paragraph (f)(2) of AD 2010-17-05 contained a typographical error in the reference to the STC number; that AD refers to “STC ST02079LA” instead of the intended “ST02076LA.” That paragraph also permits, in error, installation of the STC as an acceptable means of compliance for replacing relays R18, R19, R20, R21, R54, and R55. STC ST02076LA is a method of compliance only for relays R54 and R55.

Since the STC number was referenced incorrectly, no operator could have used STC ST02076LA as a method of compliance for relays R18, R19, R20, or R21, unless an alternative method of compliance (AMOC) was approved. No AMOCs were approved for AD 2010-17-05.

Paragraph (g)(1) of this notice of proposed rulemaking (NPRM) has been revised to specify that Boeing Alert Service Bulletin 737-28A1201, Revision 1, dated May 28, 2009, must be used to accomplish replacement of relays R18, R19, R20, and R21. Paragraph (g)(2) of this NPRM has been revised to specify that relays R54 and R55 must be replaced in accordance with either the service bulletin or by installing and maintaining UFIs using STC ST02076LA.

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 the same type design.

Proposed AD Requirements

This proposed AD would retain certain requirements of AD 2010-17-05 with new compliance times. This proposed AD would also correct the reference to the STC and specify which relays may be replaced with UFIs by installing STC ST02076LA.

Change to Existing AD

Since AD 2010-17-05 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Revised Paragraph Identifiers

Requirement in AD 2010-17-05	Corresponding requirement in this proposed AD
Paragraph (f)	Paragraph (g).
Paragraph (g)	Paragraph (h).

Costs of Compliance

We estimate that this proposed AD affects 754 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
Installation of GFI relays (retained actions from existing AD—which are restated as a convenience for operators)	8 work-hours × $85 per hour = $680	$11,010	$11,690	$8,814,260

The new requirements of this proposed AD add no additional economic burden.

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) 2010-17-05, Amendment 39-16395 (75 FR 50859, August 18, 2010), and adding the following new AD:

The Boeing Company: Docket No. FAA-2010-1199; Directorate Identifier 2010-NM-225-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by February 3, 2011.

Affected ADs

(b) This AD supersedes AD 2010-17-05, Amendment 39-16395.

Applicability

(c) This AD applies to The Boeing Company Model 737-600, -700, -700C, -800, and -900 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 737-28A1201, Revision 1, dated May 28, 2009.

Subject

(d) Joint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 28: Fuel.

Unsafe Condition

(e) This AD was prompted by fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent pump housing burn-through due to electrical arcing, which could create a potential ignition source inside a fuel tank. This condition, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

Compliance

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

Replacement or Installation

(g) Within 60 months after the effective date of this AD, do the actions required in paragraphs (g)(1) and (g)(2) of this AD.

(1) Replace the power control relays that are located in the R18, R19, R20, and R21 positions in the P91 and P92 power distribution panels for the fuel boost pumps with new, improved relays, part number KDAG-X4F-001, having a ground fault interrupter (GFI) feature, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-28A1201, Revision 1, dated May 28, 2009.

(2) Replace the power control relays that are located in the R54 and R55 positions in the P91 and P92 power distribution panels for the fuel override pumps, in accordance with the actions required in paragraph (g)(2)(i) or (g)(2)(ii) of this AD.

(i) Replace with new, improved relays, part number KDAG-X4F-001, having a GFI feature, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-28A1201, Revision 1, dated May 28, 2009.

(ii) Install and maintain TDG Aerospace universal fault interrupters (UFIs) using Supplemental Type Certificate ST02076LA, issued October 26, 2007.

Note:

Boeing Alert Service Bulletin 737-28A1201, Revision 1, dated May 28, 2009, refers to Honeywell Service Bulletin 1151932-24-61 and Honeywell Service Bulletin 1151934-24-62, both Revision 5, both dated May 25, 2009, as additional sources of guidance for replacement of the power control relays in the P91 and P92 power distribution panels.

Credit for Actions Accomplished in Accordance With Previous Service Information

(h) Actions done before the effective date of this AD in accordance with Boeing Alert Service Bulletin 737-28A1201, dated February 19, 2007, are acceptable for compliance with the requirements of paragraphs (g)(1) and (g)(2)(i) of this AD, provided that Revision 5 of Honeywell Service Bulletins 1151932-24-61 and 1151934-24-62, both dated May 25, 2009, is used as an additional source of guidance.

Alternative Methods of Compliance (AMOCs)

(i)(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 e-mailed to: [e-mail].

(2) Before using any approved AMOC, notify your Principal Maintenance Inspector or Principal Avionics Inspector, as appropriate, or lacking a principal inspector, your local Flight Standards District Office.

Related Information

(j) 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, Washington 98057-3356; telephone [phone]; fax [phone].

(k) 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]; e-mail [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 December 10, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.