Document ID: FAA-2009-0913-0001
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes
Posted Date: 2009-10-19T04:00Z

[Federal Register: October 19, 2009 (Volume 74, Number 200)]
[Proposed Rules]               
[Page 53442-53445]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19oc09-24]                         

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2009-0913; Directorate Identifier 2009-NM-101-AD]
RIN 2120-AA64

 
Airworthiness Directives; Boeing Model 737-600, -700, -700C, -
800, and -900 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, and -900 series 
airplanes. This proposed AD would require inspections for scribe lines 
in the fuselage skin at lap joints, the splice strap at certain butt 
joints, the skin or doubler at certain approved repair doublers, and 
the skin at decal locations; and related investigative and corrective 
actions if necessary. This proposed AD results from reports of scribe 
line damage found adjacent to the skin lap joints, decals, and wing-to-
body fairings. We are proposing this AD to detect and correct scribe 
lines, which can develop into fatigue cracks in the skin. Undetected 
fatigue cracks can grow and cause sudden decompression of the airplane.

DATES: We must receive comments on this proposed AD by December 3, 
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-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

[[Page 53443]]

(telephone 800-647-5527) is in the ADDRESSES section. Comments will be 
available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT: Wayne Lockett, Aerospace Engineer, 
Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 
1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 
917-6447; 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-2009-0913; 
Directorate Identifier 2009-NM-101-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 received reports indicating that scribe lines have been 
found by multiple operators on Boeing Model 737-600, -700, -700C, -800, 
and -900 series airplanes. The scribe lines appear to have been made on 
the skin when sealant was removed as part of preparing the airplane for 
repainting. One Model 737-700 operator reported scribe lines found 
around the wing-to-body fairing between stringer 26L and stringer 25R 
at station (STA) 727D to STA 727E. A second Model 737-700 operator 
reported six vertical scribe lines up to 42 inches long on the upper 
aft fuselage between stringer 5R and stringer 9R at STA 847 to STA 887. 
Another 737-700 operator reported scribe lines along stringer 24L and 
stringer 24R between STA 178 to STA 500B. The depth of the scribe lines 
ranged from 0.001 inch to 0.004 inch. The airplanes had accumulated 
between 595 and 17,571 total flight cycles. No cracks as a result of 
scribe lines found on Model 737-600, -700, -700C, -800, and -900 
airplanes have been reported to Boeing.

Related ADs

    This proposed AD is similar to two existing ADs. AD 2006-07-12, 
amendment 39-14539 (71 FR 16211, March 31, 2006), applies to Boeing 
Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. AD 
2007-19-07, amendment 39-15198 (72 FR 60244, October 24, 2007), applies 
to Boeing Model 757-200, -200PF, and -200CB series airplanes. Those ADs 
require inspections to detect scribe lines in the fuselage skin at 
certain lap joints, butt joints, external repair doublers, and other 
areas; and related investigative/corrective actions if necessary. Those 
actions resulted from reports of fuselage skin cracks adjacent to the 
skin lap joints on airplanes that had scribe lines.

Relevant Service Information

    We have reviewed Boeing Alert Service Bulletin 737-53A1289, dated 
January 14, 2009. That service bulletin describes procedures for 
inspecting for scribe lines in the fuselage skin at lap joints, the 
splice strap at certain butt joints, the skin or doubler at certain 
approved repair doublers, and the skin at decal locations. That service 
bulletin specifies removing paint and sealant from affected areas 
before the initial inspection. The service bulletin specifies that the 
compliance time for the inspections ranges between before accumulating 
14,000 total flight cycles plus the first scribe line opportunity, and 
75,000 total flight cycles, depending on the inspection location, or 
within 4,000 flight cycles after the date the service bulletin was 
issued (whichever occurs later).
    That service bulletin specifies related investigative and 
corrective actions. The related investigative actions include 
performing repetitive detailed, high frequency eddy current, 
ultrasonic, and/or ultrasonic phased array inspections of the scribe 
lines to detect cracks. The repetitive inspection interval ranges 
between 1,000 and 10,000 flight cycles, depending on the condition 
found. The corrective actions include repairing scribe lines and 
cracks. The service bulletin specifies to repair cracks before further 
flight.
    That service bulletin also specifies repairing scribe lines before 
further flight, except when a limited return to service (LRTS) program 
for qualifying scribe lines would allow return to service for a limited 
period before scribe lines are repaired. The LRTS program includes 
repetitive inspections to detect cracks where scribe lines are found. 
To qualify for an LRTS program, scribe lines must meet certain criteria 
based on their depth and location. That service bulletin specifies 
final repair by using the structural repair manual or contacting Boeing 
for instructions, which would eliminate the need for the repetitive 
inspections of the LRTS program. The repetitive intervals for the LRTS 
program range from 2,500 flight cycles to 10,000 flight cycles after 
the scribe line is found, depending on the inspection location.
    That service bulletin notes that certain inspections would not be 
necessary under the following conditions:
     The airplane has never been stripped or repainted, or the 
airplane was stripped or repainted after July 1, 2007.
     The airplane has never had decals installed, or decals 
were installed after July 1, 2007.
     For each repair, the airplane has never been stripped or 
repainted since the repair was installed or the repair was installed 
after July 1, 2007.
     The area under the wing-to-body fairings has never been 
stripped or repainted or the airplane was stripped or repainted after 
July 1, 2007.
     No sealant has been removed except in accordance with the 
specified sealant removal processes given in Appendix A of the service 
bulletin.
    That service bulletin specifies submitting inspection results to 
Boeing. The service bulletin also provides procedures for addressing 
scribe lines detected before the initial inspection threshold.

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 same type design. 
This proposed AD would require accomplishing the actions specified in 
the service information described previously, except as discussed under 
``Differences Between the Proposed AD and Service Bulletin.'' The 
proposed AD would also require sending the inspection results to 
Boeing.

Differences Between the Proposed AD and Service Bulletin

    Where the service bulletin specifies contacting the manufacturer 
for instructions on how to repair certain conditions, this proposed AD 
would require repairing those conditions in one of the following ways:
     Using a method that we approve; or
     Using data that meet the certification basis of the 
airplane, and that have been approved by an Authorized Representative 
for the

[[Page 53444]]

Boeing Commercial Airplanes Delegation Option Authorization 
Organization whom we have authorized to make those findings.

Costs of Compliance

    We estimate that this proposed AD would affect 782 airplanes of 
U.S. registry. The following table provides the estimated costs for 
U.S. operators to comply with this proposed AD.

                                                                                     Table--Estimated Costs
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                                                                                                                                   Number of
                                                      Average                                                                        U.S.-
                Action                  Work hours   labor rate     Parts                      Cost per product                    registered                      Fleet cost
                                                      per hour                                                                     airplanes
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Inspection...........................           53          $80           $0  $4,240 per inspection cycle.......................          782  $3,315,680 per inspection cycle.
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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), 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-2009-0913; Directorate Identifier 2009-
NM-101-AD.

Comments Due Date

    (a) We must receive comments by December 3, 2009.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Boeing Model 737-600, -700, -700C, -800, 
and -900 series airplanes, certificated in any category, as 
identified in Boeing Alert Service Bulletin 737-53A1289, dated 
January 14, 2009.

Subject

    (d) Air Transport Association (ATA) of America Code 53: 
Fuselage.

Unsafe Condition

    (e) This AD results from reports of scribe line damage found 
adjacent to the skin lap joints, decals, and wing-to-body fairings. 
The Federal Aviation Administration is issuing this AD to detect and 
correct scribe lines, which can develop into fatigue cracks in the 
skin. Undetected fatigue cracks can grow and cause sudden 
decompression 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.

Inspection

    (g) At the applicable times specified in paragraph 1.E., 
``Compliance,'' of Boeing Alert Service Bulletin 737-53A1289, dated 
January 14, 2009 (``the service bulletin''), except as provided in 
paragraph (h) of this AD, do detailed external inspections for 
scribe lines in the fuselage skin at lap joints, the splice strap at 
certain butt joints, the skin or doubler at certain approved repair 
doublers, and the skin at decals; and do all applicable related 
investigative and corrective actions, by accomplishing all actions 
specified in the Accomplishment Instructions of the service 
bulletin, except as provided by paragraph (i) of this AD.

    Note 1:  The inspection exceptions described in subparagraphs 
1.a. through 1.e. in paragraph 1.E., ``Compliance,'' of Boeing Alert 
Service Bulletin 737-53A1289, dated January 14, 2009, apply to this 
AD.

Exceptions to Service Bulletin Specifications

    (h) Where Boeing Alert Service Bulletin 737-53A1289, dated 
January 14, 2009, specifies a compliance time after the date on the 
service bulletin, this AD requires compliance within the specified 
compliance time after the effective date of this AD.
    (i) Where Boeing Alert Service Bulletin 737-53A1289, dated 
January 14, 2009, specifies to contact Boeing for appropriate 
action, accomplish applicable actions using a method approved in 
accordance with the procedures specified in paragraph (k) of this 
AD.

Report

    (j) At the applicable time specified in paragraph (j)(1) or 
(j)(2) of this AD: Submit a report of the findings (both positive 
and negative) of the inspections required by paragraph (g) of this 
AD. You may use Appendix B of Boeing Alert Service Bulletin 737-
53A1289, dated January 14, 2009. Send the report to Boeing 
Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207. 
The report must contain, at a minimum, the inspection results, a 
description of any discrepancies found, the airplane serial number, 
and the number of flight cycles and flight hours on the airplane. 
Under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 
et seq.), the Office of Management and Budget (OMB) has approved the 
information collection requirements contained in this AD and has 
assigned OMB Control Number 2120-0056.

[[Page 53445]]

    (1) If the inspection was done on or after the effective date of 
this AD: Submit the report within 30 days after the inspection.
    (2) If the inspection was done before the effective date of this 
AD: Submit the report within 30 days after the effective date of 
this AD.

Alternative Methods of Compliance (AMOCs)

    (k)(1) The Manager, Seattle Aircraft Certification Office, 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: 
Wayne Lockett, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, 
Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., 
Renton, Washington 98057-3356; telephone (425) 917-6447; 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.

    Issued in Renton, Washington, on October 5, 2009.
Ali Bahrami,
Manager, Transport Airplane Directorate, Aircraft Certification 
Service.
[FR Doc. E9-24986 Filed 10-16-09; 8:45 am]

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