E9-6217. Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Supplemental notice of proposed rulemaking (NPRM); reopening of comment period.

SUMMARY:

We are revising an earlier proposed airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, -800 and -900 series airplanes. The original NPRM would have required sealing the fasteners on the front and rear spars inside the main fuel tank and on the lower panel of the center fuel tank, inspecting the wire bundle support installation in the equipment cooling system bays to identify the type of clamp installed and determine whether the Teflon sleeve is installed, and doing related corrective actions if necessary. We subsequently issued a supplemental NPRM to revise the compliance time for the corrective actions specified in the original NPRM. This action resulted from a design review of fuel tank systems. This second supplemental revises the original NPRM by clarifying the applicability of certain actions for certain airplanes. We are proposing this second supplemental NPRM to prevent arcing at certain fuel tank fasteners in the event of a lightning strike or fault current event, which, 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 supplemental NPRM by April 17, 2009.

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 or 425-227-1152.

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:

Samuel Spitzer, 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-2007-28348; Directorate Identifier 2007-NM-060-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 issued a supplemental notice of proposed rulemaking (NPRM) (the “first supplemental NPRM”) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to certain Boeing Model 737-600, -700, -700C, -800 and -900 series airplanes. The first supplemental NPRM was published in the Federal Register on January 2, 2008 (73 FR 73). That first supplemental NPRM proposed to require sealing the fasteners on the front and rear spars inside the main fuel tank and on the lower panel of the center fuel tank, inspecting the wire bundle support installation in the equipment cooling system bays to identify the type of clamp installed and determine whether the Teflon sleeve is installed, and doing related corrective actions if necessary.

Actions Since Supplemental NPRM Was Issued

Since we issued the first supplemental NPRM, Boeing has revised Boeing Alert Service Bulletin 737-57A1279, dated January 24, 2007, (which we referred to as the appropriate source of service information in the first supplemental NPRM), because certain airplanes were assigned to an incorrect group number. Additional work is necessary for the mis-assigned airplanes. The additional work includes sealing the fuel tank fastener and general visual inspections of the wire bundle support installation, as applicable. We have reviewed Boeing Alert Service Bulletin 737-57A1279, Revision 1, dated September 25, 2008 (“Revision 1 of the service bulletin”). Revision 1 of the service bulletin includes a change to the service bulletin effectivity as well as changes to the access instructions for the Krueger flap operation.

Comments

We gave the public the opportunity to participate in developing this AD. We considered the comment received.

Request for More Detailed Information in Airplane Maintenance Manuals (AMMs)

Continental Airlines (CAL) is concerned that not enough attention has been given in the proposed AD to ensure that the specific detailed inspections are preserved for the long-term operation of the CAL fleet. CAL notes that the AMM includes only generic information. CAL states that including information detailed by the airplane's production drawings must be available in manuals that are routinely used by maintenance personnel. Including this information will prevent inadvertent reversal of the design configuration that can lead to creating potential ignition sources.

We infer that CAL would like us to revise the first supplemental NPRM to include an action to revise maintenance documents that are routinely used by maintenance personnel. We partially agree. We agree that ensuring that the requirements of the proposed AD are maintained throughout the life of the airplane maintains the required level of safety for this design. We disagree with delaying the issuance of the AD while the manufacturer works through its processes to develop revisions to the maintenance documents. We have determined that an unsafe condition exists and that the actions proposed in this second supplemental NPRM must be mandated in a timely fashion to ensure continued operational safety. If the revised maintenance documents are available and approved, we might consider further rulemaking at that time.

In addition, we note that as a result of CAL's comment, we have initiated discussions with Boeing about including more detail in the Instructions for Continued Airworthiness (ICA) to ensure that the proposed requirements are maintained throughout the life of the airplane. We have not changed the supplemental NPRM regarding this issue.

Explanation of Additional Change

We have added a new paragraph (d) to this second supplemental NPRM to identify the Air Transport Association (ATA) of America code for the unsafe condition. We have re-lettered subsequent paragraphs accordingly.

FAA's Determination and Proposed Requirements of the Supplemental NPRM

We are proposing this supplemental NPRM because we evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of the same type design. Certain changes described above expand the scope of the original NPRM. As a result, we have determined that it is necessary to reopen the comment period to provide additional opportunity for the public to comment on this second supplemental NPRM.

Costs of Compliance

There are about 1,754 airplanes of the affected design in the worldwide fleet; of these, 645 airplanes are U.S. registered. The following table provides the estimated costs for U.S. operators to comply with this second supplemental NPRM, at an average hourly labor rate of $80.

Estimated Costs

Action	Group	Work hours	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Sealant application	1	62	$4,960	586	$2,906,560
	2	28	2,240	44	98,560
	3	28	2,240	15	33,600
Inspection	1	4	320	586	187,520
	2	4	320	44	14,080
	3	2	160	15	2,400

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), 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

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 AD:

Boeing: Docket No. FAA-2007-28348; Directorate Identifier 2007-NM-060-AD.

Comments Due Date

(a) We must receive comments by April 17, 2009.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Model 737-600, -700, -700C, -800 and -900 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 737-57A1279, Revision 1, dated September 25, 2008.

Subject

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

Unsafe Condition

(e) This AD results from a design review of the fuel tank systems. The Federal Aviation Administration is issuing this AD to prevent arcing at certain fuel tank fasteners in the event of a lightning strike or fault current event, which, in combination with flammable fuel vapors, 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.

Fastener Sealant

(g) Within 60 months after the effective date of this AD: Seal the fasteners on the front and rear spars inside the main fuel tank and on the lower panel of the center fuel tank, as applicable, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1279, Revision 1, dated September 25, 2008.

Inspection

(h) Within 60 months after the effective date of this AD: Perform a general visual inspection of the wire bundle support installation in the equipment cooling system bays to identify the type of clamp installed, and determine whether the Teflon sleeve is installed. Do these actions in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1279, Revision 1, dated September 25, 2008 (“the service bulletin”). Do all applicable corrective actions before further flight in accordance with the service bulletin.

Actions Accomplished Previously

(i) Actions done before the effective date of this AD in accordance with Boeing Alert Service Bulletin 737-57A1279, dated January 24, 2007, are acceptable for compliance with the corresponding requirements of this AD only for the following line numbers (L/Ns): LNs 1 through 570 inclusive, and L/Ns 1692 through 1754 inclusive.

Alternative Methods of Compliance (AMOCs)

(j)(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: Samuel Spitzer, Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

(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, in the FAA Flight Standards District Office (FSDO), or lacking a principal inspector, your local FSDO. The AMOC approval letter must specifically reference this AD.

Issued in Renton, Washington, on March 10, 2009.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.