2010-18017. Airworthiness Directives; The Boeing Company Model 757 Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede an existing airworthiness directive (AD) that applies to all Model 757 airplanes. The existing AD currently requires sealing the fasteners on the front and rear spars inside the left and right main fuel tanks and on the rear spar and lower panel of the center fuel tank. That AD also requires inspections of the wire bundle support installations to verify if certain clamps are installed and if Teflon sleeving covers the wire bundles inside the left and right equipment cooling system bays, on the left and right rear spars, and on the left and right front spars; and corrective actions if necessary. This proposed AD would also require sealing the additional fasteners on the rear spar inside the left and right main fuel tanks. This proposed AD results from a fuel system review conducted by the manufacturer. We have received reports from the manufacturer that additional fasteners in the main fuel tanks must be sealed for lightning strike protection. We are proposing this AD to detect and correct improper wire bundle support installation and sleeving and to prevent improperly sealed fasteners in the main and center fuel tanks from becoming an ignition source, in the event of a fault current or lightning strike, which could result in a fuel tank explosion and consequent loss of the airplane.

DATES:

We must receive comments on this proposed AD by September 7, 2010.

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: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, 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]; 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 (telephone [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Tak Kobayashi, Aerospace Engineer, Propulsion Branch, ANM-140S, 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-2010-0698; Directorate Identifier 2009-NM-264-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 October 24, 2008, we issued AD 2008-23-19, Amendment 39-15740 (73 FR 71534, November 25, 2008), for all Model 757 series airplanes. That AD requires sealing the fasteners on the front and rear spars inside the left and right main fuel tanks and on the rear spar and lower panel of the center fuel tank. That AD also requires inspections of the wire bundle support installations to verify if certain clamps are installed and if Teflon sleeving covers the wire bundles inside the left and right equipment cooling system bays, on the left and right rear spars, and on the left and right front spars; and corrective actions if necessary. That AD resulted from a fuel system review conducted by the manufacturer. We issued that AD to detect and correct improper wire bundle support installation and sleeving and to prevent improperly sealed fasteners in the main and center fuel tanks from becoming an ignition source, in the event of a fault current, which could result in a fuel tank explosion and consequent loss of the airplane.

Clarification of Applicability

The applicability of AD 2008-23-19 refers to Model 757-200, -200CB, -200PF, and -300 series airplanes, as identified in Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007. Since that service bulletin affects all Model 757 airplanes, we have revised paragraph (c) of this AD to include all Model 757 airplanes.

Actions Since Existing AD Was Issued

Since we issued AD 2008-23-19, we have received reports that it is possible for some fuel tank fasteners, in the event of a lightning strike, to become an ignition source. Additional fasteners in the main fuel tanks must be sealed for lightning strike protection.

Relevant Service Information

AD 2008-23-19 referred to Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007, as the appropriate source of service information for the required actions. Boeing has since revised the service bulletin. Boeing Alert Service Bulletin 757-57A0064, Revision 1, dated October 5, 2009, identifies additional fasteners on the rear spar inside the left and right main fuel tanks that must be sealed.

FAA's Determination and Requirements of the Proposed AD

We have evaluated all pertinent information and identified an unsafe condition that is likely to develop on other airplanes of the same type design. For this reason, we are proposing this AD, which would supersede AD 2008-23-19 and would retain the requirements of the existing AD. This proposed AD would require accomplishing the actions specified in the Relevant Service Information described previously.

Change to Existing AD

This proposed AD would retain all requirements of AD 2008-23-19. Since AD 2008-23-19 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 2008-23-19	Corresponding requirement in this proposed AD
paragraph (d)	paragraph (e)
paragraph (e)	paragraph (f)
paragraph (f)	paragraph (g)

Costs of Compliance

There are about 1,036 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Fastener Sealing and Inspections (required by AD 2008-23-19)	Up to 545 hours per airplane depending on airplane configuration	$85	$325	$46,650	667	$31,115,550
Main Tank Fastener Sealing (new proposed action)	30	85	0	2,550	667	1,700,850

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); 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

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 Amendment 39-15740 (73 FR 71534, November 25, 2008), and adding the following new AD:

The Boeing Company: Docket No. FAA-2010-0698; Directorate Identifier 2009-NM-264-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by September 7, 2010.

Affected ADs

(b) This AD supersedes AD 2008-23-19, Amendment 39-15740.

Applicability

(c) This AD applies to all The Boeing Company Model 757-200, -200CB, -200PF, and -300 series airplanes, certificated in any category.

Subject

(d) Air Transport Association (ATA) of America Code 57: Wings.

Unsafe Condition

(e) This AD results from a fuel system review conducted by the manufacturer. We have received reports from the manufacturer that additional fasteners in the main fuel tanks must be sealed for lightning strike protection. The Federal Aviation Administration is issuing this AD to detect and correct improper wire bundle support installation and sleeving and to prevent improperly sealed fasteners in the main and center fuel tanks from becoming an ignition source, in the event of a fault current or lightning strike, which could result in a fuel tank explosion and consequent loss of the airplane.

Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Restatement of Requirements of AD 2008-23-19, With Revised Service Information

Fastener Sealing and Inspections

(g) Within 60 months after December 30, 2008 (the effective date of AD 2008-23-19), seal the applicable fasteners and do the general visual inspections of the wire bundle support installations, and do all the applicable corrective actions before further flight, by accomplishing all of the applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007; or Part 1 through Part 10 of the Work Instructions of Boeing Alert Service Bulletin 757-57A0064, Revision 1, dated October 5, 2009.

New Requirements of This AD

Fastener Sealing on the Rear Spar

(h) For airplanes on which Boeing Alert Service Bulletin 757-57A0064, dated July 16, 2007, was done: Within 60 months after December 30, 2008 (the effective date of AD 2008-23-19), seal the fasteners on the rear spar inside the left and right main fuel tanks, in accordance with Part 11 of the Work Instructions of Boeing Alert Service Bulletin 757-57A0064, Revision 1, dated October 5, 2009.

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. Send information to ATTN: Tak Kobayashi, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone]. Information may be e-mailed to: [e-mail].

(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 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.

(3) AMOCs approved previously in accordance with AD 2008-23-19, Amendment 39-15740, are approved as AMOCs for the corresponding provisions of paragraph (g) of this AD.

Issued in Renton, Washington, on July 15, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.