Document ID: FAA-2008-0669-0007
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Boeing Co. Model 737-600, -700, and -800 Series Airplanes
Posted Date: 2010-01-12T05:00Z

[Federal Register: January 12, 2010 (Volume 75, Number 7)]
[Rules and Regulations]               
[Page 1536-1538]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr12ja10-6]                         

[[Page 1536]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2008-0669; Directorate Identifier 2007-NM-350-AD; 
Amendment 39-16166; AD 2010-01-08]
RIN 2120-AA64

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

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: We are adopting a new airworthiness directive (AD) for certain 
Model 737-600, -700, and -800 series airplanes. This AD requires an 
inspection of the free flange, vertical web, and radius between the 
free flange and vertical web of the lower stringers of the wing center 
section for drill starts, and applicable related investigative and 
corrective actions. This AD results from drill starts being found on 
the free flange of the lower stringers of the wing center section 
during a quality assurance inspection at the final assembly plant. We 
are issuing this AD to prevent cracks from propagating from drill 
starts in the free flange, vertical web, and radius between the free 
flange and vertical web of the lower stringers of the wing center 
section lower stringers, which could cause a loss of structural 
integrity of the wing center section and may result in a fuel leak.

DATES: This AD is effective February 16, 2010.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in the AD as of February 16, 
2010.

ADDRESSES: 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 me.boecom@boeing.com; 
Internet https:[sol][sol]www.myboeingfleet.com.

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 AD, the regulatory evaluation, 
any comments received, and other information. The address for the 
Docket Office (telephone 800-647-5527) is the Document Management 
Facility, U.S. Department of Transportation, Docket Operations, M-30, 
West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., 
Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT: Nancy Marsh, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356, telephone (425) 
917-6440; fax (425) 917-6590.

SUPPLEMENTARY INFORMATION:

Discussion

    We issued a supplemental notice of proposed rulemaking (NPRM) to 
amend 14 CFR part 39 to include an airworthiness directive (AD) that 
would apply to certain Model 737-600, -700, and -800 series airplanes. 
That supplemental NPRM was published in the Federal Register on March 
6, 2009 (74 FR 9776). That supplemental NPRM proposed to require an 
inspection of the free flange, vertical web, and radius between the 
free flange and vertical web of the lower stringers of the wing center 
section for drill starts, and applicable related investigative and 
corrective actions.

Comments

    We gave the public the opportunity to participate in developing 
this AD. We considered the comments received from the commenters.

Support for the Supplemental NPRM

    Air Transport Association (ATA), on behalf of its member, 
Continental Airlines (CAL), expresses support for the compliance time.

Request To Align NPRMs Affecting Areas Under Enhanced Airworthiness 
Program for Airplane Systems (EAPAS) Regulations or Maintenance 
Planning Documents

    ATA, on behalf of its member CAL, notes that Boeing Alert Service 
Bulletin 73-57A1294, dated April 23, 2007, was issued before 
airworthiness limitations (AWLs) 28-AWL-11 and 28-AWL-12 were 
published. CAL points out that the service bulletin states to contact 
Boeing for repair instructions for crack findings to comply with the 
requirements of the supplemental NPRM. However, CAL states the 
supplemental NPRM and the service bulletin do not address how to comply 
with AWLs 28-AWL-11 and 28-AWL-12 of Section 9 of the Boeing 737-600/
700/800/900 MPD Document D626A001-CMR if the repair instructions 
require installing fasteners into the fuel tank. CAL notes that FAA 
approval of the MPD AWLs can only be granted by the Manager, Seattle 
Aircraft Certification Office (ACO), FAA.
    We infer that CAL is asking that we revise the supplemental NPRM to 
clarify whether the corrective actions are compliant with EAPAS 
regulations or MPD AWLs. We partially agree with CAL's request. We 
agree that operators benefit from notification that certain repairs 
covered by this AD are also potentially subject to compliance with the 
requirements of AD 2008-10-10, Amendment 39-15516 (73 FR 25986, May 8, 
2008). AD 2008-10-10 mandates AWLs 28-AWL-11 and 28-AWL-12 and requires 
that any new penetration into the fuel tank be approved for lightning 
considerations by the FAA, Seattle ACO.
    We disagree that a change to the supplemental NPRM is necessary. On 
April 15, 2009, Boeing issued MultiOperator Message (MOM) MOM-09-0178-
01B, applicable to the following ADs:
     AD 2008-04-11, Amendment 39-15383 (73 FR 9666, February 
22, 2008)
     AD 2008-04-10, Amendment 39-15382 (73 FR 9668, February 
22, 2008)
     AD 2008-10-09, Amendment 39-15515 (73 FR 25970, May 8, 
2008)
     AD 2008-10-10, Amendment 39-15516 (73 FR 25986, May 8, 
2008)
     AD 2008-10-07, Amendment 39-15513 (73 FR 25977, May 8, 
2008)
     AD 2008-10-06, Amendment 39-15512 (73 FR 25990, May 8, 
2008)
     AD 2008-10-11, Amendment 39-15517 (73 FR 25974, May 8, 
2008)
     AD 2008-11-01, Amendment 39-15523 (73 FR 29414, May 21, 
2008)
     AD 2008-11-13, Amendment 39-15536 (73 FR 30737, May 29, 
2008)

This MOM notifies operators that the FAA issued an alternative method 
of compliance (AMOC) to the same ADs. This AMOC states:

    Any alteration, design change, or repair involving new 
penetrations of the fuel tanks (such as a repair with fasteners, 
adding a bracket, bulkhead fitting or equipment) or change to the 
design features of the existing equipment penetrations (such as fuel 
measuring sticks, sump drain valves, fueling manifold, fuel 
temperature sensor, and motor operated fuel shutoff valve adapter 
plate) requires approval by the FAA Seattle ACO or an Authorized 
Representative (AR) of the Boeing Commercial Airplanes Delegated 
Compliance Organization (BDCO).
    However, any alteration, design change or repair involving new 
penetrations of the fuel tanks, accomplished in accordance with an 
FAA-approved Boeing Structural Repair Manual (SRM) or Boeing Service 
Bulletin is not subject to this requirement for additional approval.

    We consider that this AMOC and the subsequent MOM supplied by 
Boeing is sufficient notification and clarification

[[Page 1537]]

because the MOM states that certain Boeing service bulletins do not 
require additional approval in accordance with AD 2008-10-10. We have 
not changed the AD in regard to this issue.

Request To Allow ARs To Approve Repairs

    ATA, on behalf of its member CAL, requests that we revise the 
supplemental NPRM to grant delegated authority to Boeing to approve 
repairs mandated by this AD and AWLs 28-AWL-11 and 28-AWL-12 of Section 
9 of the Boeing 737-600/700/800/900 MPD Document D626A001-CMR provided 
that only the fuel tank structure is affected, while the structural 
repair does not disrupt the fuel tank system. CAL states that it is 
concerned with complying with the MPD since Boeing Alert Service 
Bulletin 737-57A1294, dated April 23, 2007, was written before AWLs 28-
AWL-11 and 28-AWL-12. CAL notes that the service bulletin states to 
contact Boeing for repair instruction for crack findings. However, CAL 
notes that this AD and the service bulletin do not reference the AWLs 
in the event that Boeing repair instructions require fastener 
installation into the fuel tank. CAL points out that FAA approval to 
reference the MPD AWLs can be granted only by the Manager, Seattle ACO.
    We disagree with the request. We have approved an AMOC that allows 
designated ARs of the BDCO to approve fuel tank penetration for 
lightning considerations for several EAPAS rules. That AMOC is written 
against the specific AD requiring lightning approvals, which is not 
part of this AD. We have not changed the final rule in regard to this 
issue.

Explanation of Change Made to This AD

    We have revised this AD to identify the correct legal name of the 
manufacturer as published in the most recent type certificate data 
sheet for the affected airplane models.

Conclusion

    We reviewed the available data, including the comments received, 
and determined that air safety and the public interest require adopting 
the AD with the changes described previously. We also determined that 
these changes will not increase the economic burden on any operator or 
increase the scope of the AD.

Costs of Compliance

    We estimate that this AD affects 17 airplanes of U.S. registry. We 
also estimate that it would take 7 work-hours per product to comply 
with this AD. The average labor rate is $80 per work-hour. Based on 
these figures, we estimate the cost of this AD to the U.S. operators to 
be $9,520, or $560 per product.

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

    This AD will not have federalism implications under Executive Order 
13132. This AD will 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 this AD:
    (1) Is not a ``significant regulatory action'' under Executive 
Order 12866,
    (2) Is not a ``significant rule'' under 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.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the FAA amends 14 CFR part 39 as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new AD:

2010-01-08 The Boeing Company: Amendment 39-16166. Docket No. FAA-
2008-0669; Directorate Identifier 2007-NM-350-AD.

Effective Date

    (a) This airworthiness directive (AD) is effective February 16, 
2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to The Boeing Company Model 737-600, -700, 
and -800 series airplanes, certificated in any category, as 
identified in Boeing Alert Service Bulletin 737-57A1294, dated April 
23, 2007.

Subject

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

Unsafe Condition

    (e) This AD results from drill starts being found on the free 
flange of the lower stringers of the wing center section during a 
quality assurance inspection at the final assembly plant. We are 
issuing this AD to prevent cracks from propagating from drill starts 
in the free flange, vertical web, and radius between the free flange 
and vertical web of the lower stringers of the wing center section 
lower stringers, which could cause a loss of structural integrity of 
the wing center section and may result in a fuel leak.

Compliance

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

Inspection and Related Investigative and Corrective Actions

    (g) Before the accumulation of 18,000 total flight cycles, or 
within 90 days after the effective date of this AD, whichever occurs 
later, do a detailed inspection of the free flange, vertical web, 
and radius between the free flange and vertical web of the lower 
stringers of the wing center section for any drill start, and do all 
applicable related investigative and corrective actions, by 
accomplishing all the applicable actions specified in paragraphs 
3.B.2 and 3.B.4 of the Accomplishment Instructions of Boeing Alert 
Service Bulletin 737-57A1294, dated April 23, 2007; except as 
provided in paragraph (h) of this AD. The applicable related 
investigative and corrective actions must be done before further 
flight.
    (h) If any crack is found during any inspection required by 
paragraph (g) of this AD, and Boeing Alert Service Bulletin 737-
57A1294, dated April 23, 2007, specifies to

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contact Boeing for appropriate action: Before further flight, repair 
the crack using a method approved in accordance with the procedures 
specified in paragraph (i) of this AD.

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: Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, 
FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., 
Renton, Washington 98057-3356; telephone (425) 917-6440; fax (425) 
917-6590. Or, e-mail information to 9-ANM-Seattle-ACO-AMOC-
Requests@faa.gov.
    (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) An AMOC that provides an acceptable level of safety may be 
used for any repair required by this AD, if it is approved by an 
Authorized Representative for the Boeing Commercial Airplanes 
Delegation Option Authorization Organization who has been authorized 
by the Manager, Seattle ACO, to make those findings. For a repair 
method to be approved, the repair must meet the certification basis 
of the airplane, and the approval must specifically refer to this 
AD.

Material Incorporated by Reference

    (j) You must use Boeing Alert Service Bulletin 737-57A1294, 
dated April 23, 2007, to do the actions required by this AD, unless 
the AD specifies otherwise.
    (1) The Director of the Federal Register approved the 
incorporation by reference of this service information under 5 
U.S.C. 552(a) and 1 CFR part 51.
    (2) 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 
me.boecom@boeing.com; Internet https://www.myboeingfleet.com.
    (3) You may review copies of the 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.
    (4) You may also review copies of the service information that 
is incorporated by reference at the National Archives and Records 
Administration (NARA). For information on the availability of this 
material at NARA, call 202-741-6030, or go to: http://
www.archives.gov/federal_register/code_of_federal_regulations/
ibr_locations.html.

    Issued in Renton, Washington, on December 23, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-31286 Filed 1-11-10; 8:45 am]
BILLING CODE 4910-13-P