[Federal Register Volume 76, Number 193 (Wednesday, October 5, 2011)]
[Proposed Rules]
[Pages 61643-61645]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2011-25579]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2011-0996; Directorate Identifier 2011-NM-068-AD]
RIN 2120-AA64


Airworthiness Directives; The Boeing Company Model 737-600, -700, 
-700C, -800, -900, and -900ER Series Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: We propose to adopt a new airworthiness directive (AD) for the 
products listed above. This proposed AD would require replacement of 
the thumbnail fairing edge seals on both sides of the engines with 
Nitronic 60 stainless steel alloy seals. This proposed AD was prompted 
by reports of excessive in-service wear damage of the thumbnail fairing 
edge seal and the fan cowl panel rub strip and fan cowl skin assembly. 
We are proposing this AD to prevent failure of the fire seal, which 
could allow a fire in the fan compartment to spread beyond the firewall 
and reach the flammable fluid leakage zones, resulting in an 
uncontrolled fire.

DATES: We must receive comments on this proposed AD by November 21, 
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: 202-493-2251.
     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 206-
544-5000, extension 1; fax 206-766-5680; e-mail [email protected]; 
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: 800-647-5527) is in the ADDRESSES 
section. Comments will be available in the AD docket shortly after 
receipt.

FOR FURTHER INFORMATION CONTACT: Chris Parker, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification Office 
(ACO), 1601 Lind Avenue, SW., Renton, Washington 98057-3356; phone: 
425-917-6496; fax: 425-917-6590; e-mail: [email protected].

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-2011-0996; 
Directorate Identifier 2011-NM-068-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 reports of repetitive occurrences of excessive in-
service wear damage of the thumbnail fairing edge seal and of the fan 
cowl panel rub strip and fan cowl skin assembly. Identical abrasion 
damage was also reported at the location where the thumbnail fairing 
edge seal rests against the top surface of the hinge beam forward 
firewall. This condition, if not corrected, could result in failure of 
the fire seal, which could allow a fire in the fan compartment to 
spread beyond the firewall and reach the flammable fluid leakage zones, 
resulting in an uncontrolled fire.

Relevant Service Information

    We reviewed Boeing Special Attention Service Bulletin 737-54-1046, 
dated February 16, 2011. That service bulletin describes procedures for 
replacing the thumbnail fairing edge seals on both the left side and 
the right side of both engine 1 and engine 2 with new Nitronic 60 
stainless steel alloy seals.

FAA's Determination and Proposed AD Requirements

    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. This proposed AD would require accomplishing the actions 
specified in the service information described previously.

[[Page 61644]]

Costs of Compliance

    We estimate that this proposed AD affects 989 airplanes of U.S. 
registry. We estimate the following costs to comply with this proposed 
AD:

                                                 Estimated Costs
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                                                                                    Cost per       Cost on U.S.
              Action                        Labor cost            Parts cost        product         operators
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Replace thumbnail faring edge       6 work-hours x $85 per             $2,032           $2,542       $2,514,038
 seals.                              hour = $510.
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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.


Sec.  39.13  [Amended]

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

The Boeing Company: Docket No. FAA-2011-0996; Directorate Identifier 
2011-NM-068-AD.

Comments Due Date

    (a) We must receive comments by November 21, 2011.

Affected ADs

    (b) None.

Applicability

    (c) 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 
737-54-1046, dated February 16, 2011.

Subject

    (d) Joint Aircraft System Component (JASC)/Air Transport 
Association (ATA) of America Code 54: Nacelles/Pylons.

Unsafe Condition

    (e) This AD was prompted by reports of excessive in-service wear 
damage of the thumbnail fairing edge seal and the fan cowl panel rub 
strip and fan cowl skin assembly. We are issuing this AD to prevent 
failure of the fire seal, which could allow a fire in the fan 
compartment to spread beyond the firewall and reach the flammable 
fluid leakage zones, resulting in an uncontrolled fire.

Compliance

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

Replacement of the Thumbnail Fairing Edge Seals

    (g) Within 60 months after the effective date of this AD, 
replace the thumbnail fairing edge seals, on both the left side and 
the right side of engine 1 and engine 2, with new Nitronic 60 
stainless steel alloy seals, in accordance with the Accomplishment 
Instructions of Boeing Special Attention Service Bulletin 737-54-
1046, dated February 16, 2011.

Alternative Methods of Compliance (AMOCs)

    (h)(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: [email protected].
    (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.

Related Information

    (i) For more information about this AD, contact Chris Parker, 
Aerospace Engineer, Propulsion Branch, ANM-140S, FAA, Seattle 
Aircraft Certification Office (ACO), 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356; phone: 425-917-6496; fax: 425-917-6590; e-
mail: [email protected].
    (j) 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 
206-544-5000, extension 1; fax 206-766-5680; e-mail 
[email protected]; Internet https://www.myboeingfleet.com. You 
may review copies of the referenced service information at the FAA, 
Transport Airplane Directorate, FAA, 1601 Lind Avenue, SW., Renton, 
Washington 98057-3356. For information on the availability of this 
material at the FAA, call 425-227-1221.


[[Page 61645]]


    Issued in Renton, Washington, on September 22, 2011.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. 2011-25579 Filed 10-4-11; 8:45 am]
BILLING CODE 4910-13-P