
[Federal Register: April 7, 2009 (Volume 74, Number 65)]
[Proposed Rules]               
[Page 15683-15685]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr07ap09-12]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0288; Directorate Identifier 2008-NM-214-AD]
RIN 2120-AA64

 
Airworthiness Directives; Boeing 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 
certain Boeing Model 737-600, -700, -700C, -800, -900 and -900ER series 
airplanes. This proposed AD would require modifying the fluid drain 
path in the wing leading edge area, forward of the wing front spar and 
doing all applicable related investigative and corrective actions. This 
proposed AD results from a report received of leaking fuel from the 
wing leading edge area at the inboard end of the number 5 leading edge 
slat. We are proposing this AD to prevent flammable fluids from 
accumulating in the wing leading edge and draining inboard and onto the 
engine exhaust nozzle, which could result in a fire.

DATES: We must receive comments on this proposed AD by May 22, 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: 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: U.S. Department of Transportation, Docket 
Operations, M-

[[Page 15684]]

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 206-
544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; 
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 800-647-5527) is in the 
ADDRESSES section. Comments will be available in the AD docket shortly 
after receipt.

FOR FURTHER INFORMATION CONTACT: Sam Spitzer, Aerospace Engineer, 
Propulsion Branch, ANM-140S, FAA, Seattle Aircraft Certification 
Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone 
(425) 917-6510; fax (425) 917-6590.

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-2009-0288; 
Directorate Identifier 2008-NM-214-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 have been notified that leaking fuel from the wing leading edge 
area at the inboard end of the number 5 leading edge slat was 
discovered during a post-flight inspection on a Model 737 airplane with 
a fuel quantity of over 2,500 lbs. Subsequent investigation found that 
the leak occurred in an area of the front spar that does not have a 
proper drain path and appears to have been caused by a loose retaining 
nut of the slat track down stop. This led to the fuel draining onto the 
engine exhaust nozzle. This condition, if not corrected, could result 
in flammable fluids accumulating in the wing leading edge and draining 
inboard and onto the engine exhaust nozzle, which could result in a 
fire.

Relevant Service Information

    We have reviewed Boeing Special Attention Service Bulletin 737-57-
1293, dated November 13, 2008 (``the service bulletin''). The service 
bulletin describes procedures for modifying the fluid drain path in the 
wing leading edge area, forward of the wing front spar.
    For Group 1 airplanes, the modification includes applying sealant 
to the cavities between the inboard slat track ribs and leading edge 
lower panels at certain slat stations in the left and right wings; 
installing a flame arrestor tube through the vapor barrier rib at the 
outboard leading edge strakelet box to direct fluids to the strut drain 
system; applying sealant to create a form-in-place gasket at the 
blowout door located under the strakelet box to prevent fluids from 
leaking onto the engine exhaust nozzle; replacing the existing seal in 
the fuel shut-off valve access door with a bulb seal to prevent 
flammable fluid leakage onto the engine exhaust nozzle; trimming the 
blowout door hinge; and related investigative and corrective actions if 
necessary. The related investigative and corrective actions include 
doing a leak test and reapplying sealant.
    For Group 2 airplanes, the modification includes removing the 
parting agent and sealant at the lower leading edge access panel 
immediately outboard of the fuel shutoff valve access door in the left 
and right wings, and installing new parting agent and sealant; and 
doing related investigative and corrective actions if necessary. The 
related investigative actions include inspecting the blowout door hinge 
for trim and doing a leak test. The corrective actions include trimming 
the blowout door hinge and reapplying sealant.

FAA's Determination and Requirements of this Proposed AD

    We are proposing this AD because we evaluated all relevant 
information and determined the unsafe condition described previously is 
likely to exist or develop in other products of the(se) same type 
design(s). This proposed AD would require accomplishing the actions 
specified in the service information described previously.

Costs of Compliance

    We estimate that this proposed AD would affect 754 airplanes of 
U.S. registry. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

                                                                Table 1--Estimated Costs
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                                                       Average
                Action                   Work hours   labor rate     Parts       Cost per        Number of U.S.-                  Fleet cost
                                                       per hour                  product      registered airplanes
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Modification, Group 1.................           45          $80       $1,545       $5,145  Up to 754...............  Up to $3,879,330.
Install parting agent Group 2.........           23           80         None        1,840  Up to 754...............  Up to $1,387,360.
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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

[[Page 15685]]

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.


Sec.  39.13  [Amended]

    2. The FAA amends Sec.  39.13 by adding the following new AD:

Boeing: Docket No. FAA-2009-0288; Directorate Identifier 2008-NM-
214-AD.

Comments Due Date

    (a) We must receive comments by May 22, 2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 737-600, -700, -700C, -800, 
-900 and -900ER series airplanes, certificated in any category, as 
identified in Boeing Special Attention Service Bulletin 737-57-1293, 
dated November 13, 2008.

Unsafe Condition

    (d) This AD results from a report received of leaking fuel from 
the wing leading edge area at the inboard end of the number 5 
leading edge slat. We are issuing this AD to prevent flammable 
fluids from accumulating in the wing leading edge and draining 
inboard and onto the engine exhaust nozzle, which could result in a 
fire.

Compliance

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

Corrective Actions

    (f) Within 24 months after the effective date of this AD, modify 
the fluid drain path in the wing leading edge area, forward of the 
wing front spar, and do all applicable related investigative and 
corrective actions, by accomplishing all applicable actions 
specified in the Accomplishment Instructions of Boeing Special 
Attention Service Bulletin 737-57-1293, dated November 13, 2008. Do 
all applicable related investigative and corrective actions before 
further flight.

Alternative Methods of Compliance (AMOCs)

    (g)(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: Sam Spitzer, Aerospace Engineer, Propulsion Branch, ANM-140S, 
FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., 
Renton, Washington 98057-3356; telephone (425) 917-6510; fax (425) 
917-6590.
    (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 appropriate 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.

    Issued in Renton, Washington, on March 12, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-7769 Filed 4-6-09; 8:45 am]

BILLING CODE 4910-13-P
