2010-31899. Airworthiness Directives; The Boeing Company Model 737-600, -700, -700C, -800, and -900 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

We are adopting a new airworthiness directive (AD) for certain Model 737-600, -700, -700C, -800, and -900 series airplanes. This AD requires 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 AD results from reports of scribe line damage found adjacent to the skin lap joints, decals, and wing-to-body fairings. We are 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.

DATES:

This AD is effective February 1, 2011.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of February 1, 2011.

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 [phone], extension 1; fax [phone]; e-mail [e-mail]; Internet https://www.myboeingfleet.com.

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 [phone]) 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:

Wayne Lockett, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Discussion

We issued a 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, -700C, -800, and -900 series airplanes. That NPRM was published in the Federal Register on October 19, 2009 (74 FR 53442). That NPRM proposed to 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.

Comments

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

Support for the NPRM

The National Safety Transportation Board (NTSB) and Air Transport Association (ATA), on behalf of its member AirTran, support the intent of the NPRM.

Request To Refer to Latest Revision of Service Bulletin

The Boeing Company requests that we revise the NPRM to refer to the latest version of the appropriate service information, Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009.

We agree to refer to the latest version of the service information. Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, shows changes of airplane operators in Paragraph 1.A., Effectivity, and clarifies requirements for inspections of areas of the fuselage having decals. Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, does not require additional work beyond the original version of that service bulletin, which was cited as the appropriate source of service information in the NPRM. We have revised the AD requirements to refer to Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, as the appropriate source of service information, and we have added paragraph (h) to this final rule to provide credit for actions performed in accordance with Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009.

Request To Update Exception in Note 1 of the NPRM

The Boeing Company requests that we revise the NPRM to update the exception referenced in Note 1 of the NPRM because Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, adds an exception to the inspections. The additional exception is described in subparagraph 1.f. in paragraph 1.E., “Compliance,” of that service bulletin. Southwest Airlines also requests that we add the same provision. Southwest notes that the additional provision states, “If the operator's records show that decal installation and removal procedures were used, at all times since delivery, which included pre-cutting decals prior to installation on the airplane and no use of metallic tooling of any kind during the installation or removal of decals on the airplane, then the [decal] inspections [per Tables 5 through 9] are not required.”

We agree. The specified decal installation and removal procedures have been shown to not result in scribe damage to the fuselage. We have updated Note 1 in this AD to include the additional exception specified in subparagraph 1.f. in paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009.

Request To Include Training About Scribe Lines and Scratches

The National Transportation Safety Board (NTSB) is concerned that the NPRM does not address the underlying condition that mechanics and technicians do not have the knowledge, training, and awareness to recognize that minor damage to pressurized airplane skin can result in fatigue cracking, which can result in depressurization events. The NTSB requests that the FAA reexamine existing maintenance practices and training techniques to educate personnel about the serious consequences of minor scratches and scribe lines on pressurized fuselage skin panels.

We acknowledge the NTSB's concerns. However, such training is outside the scope of the AD requirements as defined in 14 CFR part 39. (Part 12 provides inspection procedures for scribe marks found before the initial inspection.) We have worked with industry groups and manufacturers to increase awareness of scribe lines and their effects on skin panels. This topic has also been addressed at Industry Steering Committee (ISC), Maintenance Steering Group (MSG), and Structures Task Group (STG) meetings. We have not changed the AD in regard to this issue.

Request To Remove Hard Time Date

Continental Airlines (Continental) requests that we review the hard time date of July 1, 2007, that is stated in “Compliance,” paragraph 1.E.1(a) through 1.E.1(e) of Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009. Continental states that a hard time date should not matter if the operator can provide documents that show sealant and decals were removed using an approved method after the operator received the airplane.

We have reviewed the hard time date, as requested by the commenter. The date of July 1, 2007, was selected because all the Boeing documentation was revised as of this date to detail the proper method for removing paint, sealant, and decals. Not all operators may have used methods equivalent to the methods stated in this documentation, but they may have used methods detailed in documentation published before this date. As a result, the date of July 1, 2007, is included appropriately in Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009. Operators may submit a request for approval of an alternative method of compliance (AMOC) if their methods for removing paint, sealant, and decals were implemented before July 1, 2007, and provide an acceptable level of safety. We have not changed the AD in regard to this issue.

Request To Incorporate Instructions into Structural Repair Manual (SRM)

Continental requests that the instructions given in Part 12 of the work instructions of Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009, be incorporated into the structural repair manual (SRM) before the release of the AD because the SRM is for non-routine or non-scheduled events. (Part 12 provides inspection procedures for scribe marks found before the initial inspection.) Continental states that the current instructions make it difficult to comply with the NPRM by the operators' mechanics because they would use the SRM only for repair to damages that are discovered or that occurred during a non-routine event.

We disagree with the request. Significant effort has been made to educate operators about the effects of scribe lines on the fuselage structure. Therefore, all mechanics should be aware of scribe lines. Also, the service bulletins pertaining to scribe lines for all Boeing models contain instructions for repairing scribe line damage found before the inspection threshold. We have not changed the AD in regard to this issue.

Request To Allow All Repairs Using the SRM

Continental requests that we revise the NPRM to allow all repairs using the SRM. Continental states that it does not agree that all repairs need to be approved by Boeing or the FAA Seattle Aircraft Certification Office, as specified in Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009, and in paragraphs (i) and (k) of the NPRM. Continental proposes that we add an exception to Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009, to allow all repairs other than repairs done for the Limited Return to Service (LTRS) program to be accomplished in accordance with the SRM or to be FAA-approved.

Continental states because the scribe lines do not result from a design deficiency, no differences exist between these repairs and any other repairs on the airplanes. Continental states that if such an exception is not allowed, operators are unfairly penalized by being forced to use Boeing's repair services. While Continental acknowledges that paragraph (k)(2) of the NPRM (now paragraph (p)(2) of the final rule) allows requests for AMOC approvals, it states that the FAA's response time to approve AMOCs does not allow airplanes to return to service in a timely manner that supports operational requirements. Continental states that this is why the designee program exists as given in section 183.29 of the Federal Aviation Regulations (14 CFR 183.29) and FAA Order 8100.15, which should not be overridden by the proposed AD.

We agree to revise the final rule to add an exception to the accomplishment instructions specified by Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009. We agree that repairs to the fuselage where the scribe line is removed are not different from other repairs to the airplane. Also, Boeing has revised the Allowable Damage section of the SRM to address scribe line damage. We have added a new paragraph (k) to the final rule to allow for repair in accordance with an FAA-approved method. We have also added Note 2 to the final rule that provides guidance for repairing scribe damage.

Request To Correct “Relevant Service Information” in NPRM

Continental requests that we correct the “Relevant Service Information” section in the NPRM because Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009, does not specify final repairs by using the SRM. Instead, Continental states that Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009, specifies to contact Boeing for final repairs.

We agree. However, this section does not appear in this final rule. We have not changed the AD in regard to this issue.

Request To Revise Exceptions for Airplanes That Have Been Scuff Sanded

Air Transport Association (ATA), on behalf of its member American Airlines (American), states that the list of exceptions in section 1.E, “Compliance,” of Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009, should be revised to specify that airplanes that have been scuff sanded and repainted do not require inspections in areas where they have been repainted. American states that it does not use complete paint on the external surfaces and leaves most of the fuselage in natural metal finish. American states that it rarely accomplishes a chemical strip of the painted stripes and that the sealant can be damaged by chemical strippers. This process does not require removal and reapplication, which might cause scribe marks.

We partially agree. The operator's unique finish on the fuselage limits the potential for the development of scribe lines. However, we do not agree that changing this AD is necessary because operators may interpret such an exception to allow sanding after paint and sealant are removed, and these methods might eliminate any evidence of scribe marks. Operators may submit requests for approval of an AMOC for their particular finish configuration. We have not changed the AD in regard to this issue.

Request To Revise Costs of Compliance

ATA, on behalf of its members Air Tran Airlines (Air Tran) and American, requests that we revise the costs of compliance. AirTran states that complying with the NPRM would cost $2,500 per airplane and that it would have to procure special tooling for each site performing the inspection. American Airlines states that complying with the NPRM without any changes would cost it $1,004,080 for labor and $3,458,455 for additional out-of-service time.

We have revised the costs of compliance to increase the labor rate from $80 to $85. However, we have not changed the costs of compliance otherwise. The cost information below describes only the direct costs of the specific actions required by this AD. Based on the best data available, the manufacturer provided the number of work hours necessary to do the required actions. This number represents the time necessary to perform only the actions actually required by this AD. We recognize that, in doing the actions required by an AD, operators might incur incidental costs in addition to the direct costs. The cost analysis in AD rulemaking actions, however, typically does not include incidental costs such as the time required to gain access and close up, time necessary for planning, or time necessitated by other administrative actions. Those incidental costs, which might vary significantly among operators, are almost impossible to calculate.

Request To Require Reporting of Only Positive Findings of Cracks

Southwest Airlines (Southwest) and Qantas request that we revise the AD to require reporting of only crack findings. Southwest notes that AD 2006-07-12, Amendment 39-14539 (71 FR 16211, March 31, 2006), a similar AD that requires inspection for scribe lines on Model 737 airplanes, requires the reporting of cracks found only during LRTS inspections, not scribe lines found as a result of the initial scribe inspections. Qantas asks why a report for a one-time inspection is required.

We agree to provide clarification of the rationale for reporting requirements and to revise the reporting requirements. The data will be used to determine if the existing inspection thresholds and the repeat inspection intervals provided in the LRTS program may be increased, which may result in less work for operators in the future. We have revised paragraph (o) of this final rule to require reporting only positive findings of cracks found during any inspections required by this AD.

Request To Add Instructions for Addressing Scribe Lines Outside Zones

Southwest requests that we revise the AD to either state how to address scribe lines found in zones outside of those zones specified in Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009, or add a statement that “no zone” scribes do not require repetitive inspections or terminating actions. Southwest did not provide justification for its request.

We disagree that revising the NPRM is necessary. This AD requires inspections and a terminating action in only the zones identified in Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009. Any zone that is not identified in Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, is not subject to inspection or repair requirements of this rule. (See paragraph 3.A. Note 13 of Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009.) We have not changed the AD in regard to this issue.

Request To Address Scribe Lines Less than 0.001 Inch Deep

Southwest requests that we revise the AD to address scribe lines that are less than 0.001 inch deep. Southwest states that Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009, states that no further inspections are required for such scribe lines, but Southwest requests that the AD specifically state that such lines do not require terminating action. Southwest asks why the compliance time is “before further flight” if no inspections are required. Southwest asks if that means no additional NDT inspections are required at the time of finding such lines.

We partially agree with the commenter's request. The compliance table in paragraph 1.E., “Compliance,” of the service bulletin requires clarification as it shows the compliance time of “before further flight” for inspecting scribe lines that are less than 0.001 inch deep. We have clarified this issue by stating in paragraph (m) of this AD that no further inspections are required provided that correct sealant removal procedures are used.

Request To Allow the Blending of Scribe Lines

Southwest requests that we revise the AD to allow operators to blend scribe lines in accordance with the SRM by treating the scribe line as a gouge or scratch. Southwest states that the 737-700 SRM does not address scribe lines in the Allowable Damage section. Southwest states that Boeing Service Bulletin 737-53A1262 (the appropriate source of service information for a one-time inspection for scribe lines and cracks in the fuselage skin at certain lap joints, butt joints, external repair doublers, and other areas in AD 2006-07-12, Amendment 39-14539 (71 FR 16211, March 31, 2006)) allows the blending of scribe lines in accordance with the SRM by treating the scribe line as a gouge or scratch. However, Southwest notes, Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009, does not allow for the same treatment, but recommends that operators contact Boeing for repair instructions.

We agree. All Boeing Model 737 SRMs were revised as a result of the scribe issue to address scribe damage in butt joints and within 1.0 inch of lap splice lower edges and external repair edges. This information is found in the Allowable Damage sections of the SRMs. We have added Note 2 to this final rule, as noted previously.

Request To Include Terminating Action for Repairing Scribe Lines

Southwest requests that accomplishing repairs or modifications in accordance with Boeing Service Bulletin 737-53-1232 be an approved method for terminating scribe line inspections. Southwest did not provide any justification for its request.

We disagree. The repair and modification specified in Boeing Service Bulletin 737-53-1232 are specifically designed for chem mill step cracking, not scribe lines. The modification specified in Boeing Service Bulletin 737-53-1232 would not meet the requirements of this AD. The modification provided in Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, does not extend a minimum of three fastener rows below any scribe line damage at a lap joint, and the doubler and tripler used on the repair specified in Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, do not extend a minimum of three fastener rows below any scribe damage at a lap joint. We have not changed the AD in regard to this issue.

Request To Include an Exception for Inspections of Areas Covered by Certain Repairs

Southwest requests that we revise the NPRM to contain a provision excluding inspections of areas that are covered by repairs that span a minimum of three rows above and below the inspection area.

We agree with the commenter. This exception is provided in other scribe line ADs for other Boeing airplane models and should apply in this AD as well. We have added paragraph (l) to this AD to provide this exception to Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009. In addition, we have also added an exception to not require removal of a repair even if it does not span a potential scribe by 3 or more fastener rows and there is no evidence of scribe lines within 10 inches of the repair.

Request To Include Exception for Inspections of Areas Under the Dorsal Fin Fairing

Southwest requests that we include an exception for inspections of areas under the dorsal fin fairing. Southwest requests that this area be treated the same as the wing-to-body fairing, i.e., if the area under the dorsal fin fairing has never been stripped or repainted since delivery, then the scribe line inspection should not be required in that area.

We agree. We have added paragraph (n) of this final rule to provide an exception for this area.

Request for Clarification of the Compliance Time

Qantas states since a scribe line can occur at any time during the service life of an airplane and at many locations, this program uses both total flight cycles and structural criticality of location to determine the inspection requirements. Qantas asks if the compliance time takes into account scribe lines induced before the first repainting of the airplane.

We agree to provide clarification. The compliance times specified in Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, do not account for scribe lines induced before the first repainting. All analysis was accomplished using the assumption that scribe lines might be induced during repainting only when the sealant is removed from lap and butt joints and around external doublers. The FAA has received no prior reports of scribe line damage on Model 737NG airplanes before the first repainting. We will investigate the reports provided by the commenter and all operators, and will take action as necessary. We have not changed the AD in regard to this issue.

Request To Omit Instructions for Restoring the Surface Finish

ATA, on behalf of its member American, requests that we do not consider as part of the AD the methodology in Part 11—“Surface Finish Restoration” of Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009. American states that it has internal processes that meet the intent of the requirement for the reapplication of removed finishes, although those processes may not be identical in material, workflow, or processes.

We partially agree with the commenter. While the unique finishes on the fuselage may warrant using different processes than those used on a typical fuselage, we disagree with the request because the commenter did not provide details on the processes that meet the intent of the AD. We will consider requests for an approval of an AMOC if data demonstrate that it meets an acceptable level of safety. We did not change the AD in regard to this issue.

Explanation of Changes Made to This AD

We have revised the “Alternative Methods of Compliance (AMOCs)” paragraph in this AD to clarify the delegation authority for the Boeing Commercial Airplanes Organization Designation Authorization. We have also revised paragraph (k) of this final rule to clarify that repairs must be made in accordance with an FAA-approved method.

Explanation of Change to Applicability

We have revised the applicability of the existing AD to identify model designations as published in the most recent type certificate data sheet for the affected models.

Conclusion

We reviewed the relevant data, considered 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.

Explanation of Change to Costs of Compliance

Since issuance of the NPRM, we have increased the labor rate used in the Costs of Compliance from $80 per work-hour to $85 per work-hour. The Costs of Compliance information, below, reflects this increase in the specified hourly labor rate.

Costs of Compliance

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

Table—Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per product	Number of U.S.-registered airplanes	Fleet cost
Inspection	53	$85	$0	$4,505 per inspection cycle	782	$3,522,910 per inspection cycle.

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

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 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:

2010-26-06 The Boeing Company: Amendment 39-16545. Docket No. FAA-2009-0913; Directorate Identifier 2009-NM-101-AD.

Effective Date

(a) This airworthiness directive (AD) is effective February 1, 2011.

Affected ADs

(b) None.

Applicability

(c) This AD applies to The Boeing Company Model 737-600, -700, -700C, -800, and -900 series airplanes, certificated in any category, as identified in Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 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 Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009 (“the service bulletin”), except as provided in paragraph (i) 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 paragraphs (j), (k), (l), (m), and (n) of this AD.

Note 1:

The inspection exceptions described in subparagraphs 1.a. through 1.f. in paragraph 1.E., “Compliance,” of Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, apply to this AD.

Credit for Actions Accomplished According to Previous Issue of Service Bulletin

(h) Actions accomplished before the effective date of this AD according to Boeing Alert Service Bulletin 737-53A1289, dated January 14, 2009, are considered acceptable for compliance with the corresponding actions specified in this AD.

Exceptions to Service Bulletin Specifications

(i) Where Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 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.

(j) Where Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, specifies to contact Boeing for appropriate action, accomplish applicable actions using a method approved in accordance with the procedures specified in paragraph (p) of this AD.

(k) Where Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, specifies to contact Boeing for instructions to repair scribe lines: Remove the scribe line damage and install a reinforcing repair using an FAA-approved method.

Note 2:

Guidance for repairing scribe damage (e.g., nicks, gouges, scratches, and corrosion) may be found in the Allowable Damage section of the appropriate Boeing 737 Structural Repair Manual (SRM).

Note 3:

Operators must obtain an approved damage tolerance evaluation for any repair installed to comply with Section 121.1109(c)(2) or 129.109(c)(2) of the Code of Federal Regulations (14 CFR 121.1109(c)(2) or 129.109(c)(2)).

(l) Inspections are not required in areas where an existing repair covers a potential scribe line or where the scribe line is within 10 inches of the repair, provided the repair spans a minimum of three fastener rows beyond each side of the potential scribe line location (perpendicular to the scribe line direction). If a repair doubler does not span the potential scribe line location by 3 or more fastener rows, but there is no evidence of scribe lines within 10 inches of the repair, then inspections under the repair are not required.

(m) Where Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, specifies a compliance time of “before further flight” for inspecting scribe lines less than 0.001 inch deep for cracks, no further inspections are required by paragraph (g) of this AD, provided that correct sealant removal procedures are used for future work at those locations.

(n) If records show that the airplane has never been stripped and repainted under the dorsal fin fairing since delivery from Boeing, then this AD does not require inspections specified in paragraph (g) of this AD for the butt joint, lap joint, and repairs in the areas under the dorsal fin fairing.

Report

(o) At the applicable time specified in paragraph (o)(1) or (o)(2) of this AD: Submit a report of positive findings of cracks found during the inspections required by paragraph (g) of this AD. You may use Appendix B of Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 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.

(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)

(p)(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 [phone]; fax [phone]. Or, e-mail information to [e-mail].

(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 Organization Designation Authorization 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

(q) You must use Boeing Service Bulletin 737-53A1289, Revision 1, dated November 18, 2009, 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 [phone], extension 1; fax [phone]; e-mail [e-mail]; 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.

(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 10, 2010.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.