2012-24809. Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to supersede two existing airworthiness directives (AD) that apply to certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. The existing AD, for certain Model 737-100, -200, and -200C series airplanes currently requires repetitive inspections of the aft end of each inboard flap track of the wing outboard flap, and corrective actions, if necessary. The existing AD, for certain Model 737-100, -200, -200C, -300, -400, and -500 series airplanes requires repetitive inspections for cracks in the upper flange of the inboard track at the rear spar attachments of each outboard flap, and corrective action, if necessary. That AD also requires, for certain airplanes, repetitive inspections for discrepancies of the rear spar attachments and cracks in the upper flange of the inboard track at the rear spar attachment of each outboard flap, and eventual rework of the flap track assembly and rear spar attachments, including replacement of the flap track with a new track, if necessary. Since we issued those ADs, we have received reports that the work sequence and procedures used during track installation could also cause loose or cracked tracks. This proposed AD would require an inspection for damage and stop-drill repairs along the flap track; an inspection for damage, cracking, and stop-drill repairs along the track webs; and an inspection for damage of the flap track web and flanges, and corrective actions if necessary. This proposed AD would also require, for certain airplanes, an inspection for signs of movement between the tapered shim and anti-fret strip, installation of the anti-fret strip, and corrosion of the tapered shim and anti-fret strip; an inspection for signs of movement, cracks and corrosion where the track is attached to the wing rear spar; an inspection for cracking of the outboard edge of the track; an inspection for cracking of the inner edge of the track; and related investigative and corrective actions if necessary. This proposed AD would also require repetitive overhauls of the flap track and repetitive post-overhaul inspections and corrective actions if necessary; an inspection to determine the part number of the flap track assembly, and replacement of affected parts if necessary; and would also add airplanes to the applicability. We are proposing this AD to detect and correct cracking and damage in the flap track, which could cause loss of the outboard trailing edge flap and consequent reduced controllability of the airplane.

DATES:

We must receive comments on this proposed AD by November 26, 2012.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• 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, WA 98124-2207; telephone [phone], extension 1; fax [phone]; 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, WA. 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: [phone]) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: [phone]; fax [phone]; email: [e-mail].

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-2012-1068; Directorate Identifier 2011-NM-073-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

On December 5, 2000, we issued AD 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000), for certain Model 737-100, -200, and -200C series airplanes. That AD requires repetitive inspections of the aft end of each inboard flap track of the wing outboard flap, and corrective actions, if necessary. That AD resulted from reports of cracking of the aft end of an inboard flap track of the wing outboard flap found on a Model 737-200 series airplane having improved flap tracks installed. The inner and outer webs of the track, as well as the upper and lower flanges, were severed. We issued that AD to detect and correct damage of the aft end of each flap track, which could result in loss of the outboard trailing edge flap and consequent loss of controllability of the airplane.

On March 8, 2002, we issued AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002), for certain Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. That AD requires, for certain airplanes, repetitive inspections for discrepancies of the rear spar attachments and cracks in the upper flange of the inboard track at the rear spar attachment of each outboard flap, and eventual rework of the flap track assembly and rear spar attachments, including replacement of the flap track with a new track, if necessary. For certain airplanes, that AD requires repetitive inspections for cracks in the upper flange of the inboard flap tracks at the rear spar attachments, and corrective action, if necessary. That AD resulted from several reports of cracking of the inboard track of the outboard flap. We issued that AD to detect and correct discrepancies of the inboard tracks of the outboard flaps, which could result in loss of the outboard trailing edge flaps and consequent reduced controllability of the airplane.

Actions Since Existing ADs 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000); and 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002); Were Issued

Since we issued ADs 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000); and 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002); we have received reports that the work sequence and procedures used during track installation could also cause loose tracks, causing the track to move laterally at the rear spar joint when full torque is applied to the forward attach bolt, putting a side load on the inboard aft attach bolt. Because of friction caused by tightening to the specified torque value, the torque applied to the bolt is not sufficient to hold the track tight against the rear spar structure. Continued operation with a cracked or loose attachment at the rear spar could cause the track to break, which could result in the loss of the outboard trailing edge flap and consequent loss of controllability of the airplane.

Relevant Service Information

We reviewed Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, for all Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This service information describes procedures for a detailed inspection for damage (cracks, nicks, corrosion pits, galling, pieces broken off) and stop-drill repairs along the full length of the upper and lower flanges of the flap track; a detailed inspection for damage, cracking, and stop-drill repairs along the full length of the track webs; an eddy current inspection for damage (including cracking) of the flap track web and flanges; and corrective actions if necessary. Corrective actions include repairing damage and replacing flap tracks.

Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, also describes, for certain airplanes, procedures for a detailed inspection for signs of movement between the tapered shim and anti-fret strip installation of the anti-fret strip, and corrosion of the tapered shim and anti-fret strip; a detailed inspection for signs of movement, cracks and corrosion of the area where the track is attached to the wing rear spar; an eddy current inspection for cracking of the outboard edge of the track adjacent to the outboard attach bolt; an ultrasonic inspection for cracking of the inner edge of the track adjacent to the outboard attach bolt; and related investigative and corrective actions if necessary. The related investigative actions (which include disassembly of the flap track-to-wing attachment) include the following inspections.

• A detailed inspection of the anti-fret strip for signs that show the strip is loose or damaged and to determine if the anti-fret strip is made of phenolic.
• A detailed inspection of the tapered shim for damage and corrosion, and to determine if the shim is made of laminated material and the shim width is less than 1.70 inches.
• A detailed inspection of the track in the area where it is fitted against the wing skin for corrosion on the surface and corrosion in the bolt holes.
• A detailed inspection of the bushing for corrosion.
• An eddy current inspection or magnetic particle inspection for cracking on the upper surface of the track flange adjacent to the inboard and outboard bolt holes.
• An eddy current inspection or magnetic particle inspection of the inboard and outboard bolt holes for cracking.

The corrective actions include installing a new anti-fret strip, tapered shim, or bushing; removing or repairing corrosion; and removing damage and replacing the flap track.

Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, also describes procedures for repetitive overhauls of the flap track and repetitive post-overhaul inspections and corrective actions if necessary.

FAA's Determination

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.

Proposed AD Requirements

This proposed AD would retain all requirements of AD 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000); and all requirements of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002). This proposed AD would require new inspections and overhauls of the flap track assembly. This proposed AD would also require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the AD and the Service Information.”

Changes to Existing ADs 2000-25-07 Amendment 39-12041 (65 FR 78913, December 18, 2000); and 2002-05-07 Amendment 39-12675 (67 FR 11891, March 18, 2002)

Since ADs 2000-25-07 Amendment 39-12041 (65 FR 78913, December 18, 2000); and 2002-05-07 Amendment 39-12675 (67 FR 11891, March 18, 2002); were issued, the AD format has been revised, and certain paragraphs have been re-arranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Revised Paragraph Identifiers

Requirement in previous ADs 2000-25-07 Amendment 39-12041 (65 FR 78913, December 18, 2000); and 2002-05-07 Amendment 39-12675 (67 FR 11891, March 18, 2002)	Corresponding requirement in this proposed AD
paragraph (a) of AD 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000)	paragraph (g).
paragraph (b) of AD 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000)	paragraph (i).
paragraph (a) of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002)	paragraph (j).
paragraph (b) of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002)	paragraph (l).
paragraph (c) of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002)	paragraph (m).
paragraph (d) of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002)	paragraph (n).
paragraph (e) of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002)	paragraph (o).

The reference to “the service bulletin” in paragraph (e) of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002) has been spelled out with the full citation, “Boeing Service Bulletin 737-57A1249, Revision 1, including Appendix A, dated June 1, 2000,” in paragraph (o) of this proposed AD. Boeing Commercial Airplanes has received an Organization Designation Authorization (ODA). We have revised paragraphs (i) and (o) of this AD to delegate the authority to approve an alternative method of compliance for any repair required by this proposed AD to the Boeing Commercial Airplanes ODA rather than a Designated Engineering Representative (DER).

Note 2 of AD 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000), has been changed to paragraph (h) of this proposed AD.

Note 3 of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002), has been changed to paragraph (k) of this proposed AD which provides credit for previous accomplishment of certain actions.

We have also revised certain headings throughout this AD.

Differences Between the Proposed AD and the Service Information

Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, specifies procedures to inspect for installation of an anti-fret strip but does not specify on-condition actions if the anti-fret strip is missing. If an anti-fret strip is not found installed, this proposed AD would require that the related investigative actions specified for anti-fret strips that have signs of damage or corrosion are done, and corrective actions if necessary, including making and installing a new anti-fret strip, are done in accordance with paragraph 3.B.5 of the Accomplishment Instructions of Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012.

Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, specifies procedures to remove certain flap track assemblies if found. This proposed AD would require an inspection to determine the part number of the flap track assembly and replacement of affected parts if necessary.

Explanation of Change to Costs of Compliance

Since issuance of AD 2002-05-07, Amendment 39-12041 (65 FR 78913, December 18, 2000), we have increased the labor rate used in the Costs of Compliance from $60 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 proposed AD affects 570 airplanes of U.S. registry.

We estimate the following costs to comply with this proposed AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Number of airplanes	Cost on U.S. operators
Detailed visual inspection [retained actions from existing AD 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000)]	6 work-hours × $85 per hour = $510	$0	$510	290	$147,900.
Detailed visual, HFEC, and ultrasonic inspections [retained actions from existing AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002)]	4 work-hours × $85 per hour = $340	$0	$340	1,100	$374,000.
Detailed and eddy current inspections [new proposed actions]	82 work-hours × $85 per hour = $6,970 per inspection cycle	$0	$6,970 per inspection cycle	570	$3,972,900 per inspection cycle.
Overhaul [new proposed action]	70 work-hours × $85 per hour = 5,950 per overhaul cycle	$20,000	$25,950 per overhaul cycle	570	$14,791,500 per overhaul cycle.

We have received no definitive data that would enable us to provide cost estimates for labor cost for repair, and parts cost for repair and replacement for the on-condition actions specified in this proposed AD. The labor cost of the replacement is $1,360 (16 work-hours × $85 per hour). We have no way of determining the number of aircraft that might need these repairs/replacements.

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 have 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 that the 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.

§ 39.13

[Amended]

2. The FAA amends § 39.13 by removing airworthiness directives (AD) 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000); and 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002); and adding the following new AD:

The Boeing Company: Docket No. FAA-2012-1068; Directorate Identifier 2011-NM-073-AD.

(a) Comments Due Date

The FAA must receive comments on this AD action by November 26, 2012.

(b) Affected ADs

This AD supersedes ADs 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000); and 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002).

(c) Applicability

This AD applies to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, certificated in any category.

(d) Subject

Joint Aircraft System Component (JASC)/Air Transport Association (ATA) of America Code 57, Wings.

(e) Unsafe Condition

This AD was prompted by reports that the work sequence and procedures used during installation of replacement tracks installed in accordance with AD 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000); or AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002); could cause loose or cracked tracks. We are issuing this AD to detect and correct cracking and damage in the flap track, which could cause loss of the outboard trailing edge flap and consequent reduced controllability of the airplane.

(f) Compliance

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

(g) Retained Repetitive Inspections

This paragraph restates the inspection required by paragraph (a) of AD 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000), with added references to a terminating action. For Model 737-100, -200, and -200C series airplanes on which the left- or right-hand inboard flap tracks of the wing outboard flap have a part number (P/N) listed in Table 1 of this AD: Do a detailed visual inspection to detect damage (corrosion, cracking) of the aft end of the left- and right-hand inboard flap tracks of the wing outboard flap, per Boeing All Operator Message (AOM) M-7200-00-01854, dated July 27, 2000, at the latest of the times specified in paragraphs (g)(1), (g)(2), and (g)(3) of this AD. Repeat the inspection thereafter at intervals not to exceed 1,200 flight cycles. Accomplishing the requirements of paragraph (p) of this AD terminates the requirements of this paragraph.

Table 1—Boeing Flap Tracks Subject to This AD

Name	Part No.
Boeing	65-46428-9
	65-46428-15
	65-46428-17
	65-46428-19
	65-46428-21
	65-46428-23
	65-46428-25
	65-46428-27
	65-46428-33
	65-46428-35

(1) Within 30 days after January 2, 2001 (the effective date of AD 2000-25-07 Amendment 39-12041 (65 FR 78913, December 18, 2000)).

(2) Within 1,200 flight cycles after the last documented inspection or overhaul of the aft end of each flap track.

(3) Before the accumulation of 15,000 total flight cycles.

(h) Retained Definition

This paragraph restates the definition specified by Note 2 of AD 2000-25-07 Amendment 39-12041 (65 FR 78913, December 18, 2000). For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate by the inspector. Inspection aids such as a mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

(i) Retained Corrective Actions

This paragraph restates the corrective actions required by paragraph (b) of AD 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000), with added reference to organization designation authorization (ODA). If any damage (corrosion, cracking) is detected during any inspection required by paragraph (g) of this AD, before further flight, repair or rework the flap track per the “Repair and Rework Instructions” specified in Boeing AOM M-7200-00-01854, dated July 27, 2000. Where that AOM specifies that the manufacturer may be contacted for disposition of certain corrective actions (i.e., repair and/or rework of the flaps), this AD requires such repair and/or rework to be done per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis of the airplane approved by a Boeing Company designated engineering representative (DER) or the Boeing Commercial Airplanes ODA who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the ODA, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD.

(j) Retained Initial Inspections

This paragraph restates the initial inspection required by paragraph (a) of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002), with added references to terminating action. For Model 737-100, -200, and -200C series airplanes with line numbers (L/N) 1 through 869 inclusive, and those airplanes with L/Ns 870 through 1585 inclusive, which either still have their original flap tracks or which have had the original flap tracks replaced with certain tracks as specified in Boeing Service Bulletin 737-57A1249, Revision 1, including Appendix A, dated June 1, 2000; except airplanes on which any replacement flap tracks were installed as specified in Boeing Service Bulletin 737-57-1203, dated November 15, 1990, or production equivalent: Within 6 months after April 22, 2002 (the effective date of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002)), accomplish the requirements of paragraphs (j)(1) and (j)(2) of this AD, according to Boeing Service Bulletin 737-57A1249, Revision 1, including Appendix A, dated June 1, 2000. Accomplishing the requirements of paragraph (p) of this AD terminates the requirements of this paragraph.

(1) Perform a detailed visual inspection for discrepancies (e.g., corrosion, or missing, damaged, or migrated anti-fret strips and tapered shims) of the rear spar attachments of the flap tracks.

(2) Perform detailed visual, high frequency eddy current (HFEC), and ultrasonic inspections for cracking in the upper flange of the inboard track of each outboard flap at the rear spar attachments.

(k) Retained Credit for Previous Actions

This paragraph restates the credit for certain previously accomplished actions specified by Note 3 of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002). This paragraph provides credit for the actions specified in paragraphs (j), (l), (m), and (n) of this AD, if those actions were performed before the effective date of this AD using Boeing Alert Service Bulletin 737-57A1249, including Appendix A, dated December 16, 1999.

(l) Retained Repetitive Inspections

This paragraph restates the repetitive inspections required by paragraph (b) of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002). For airplanes subject to the requirements of paragraph (j) of this AD: If no discrepancy is found during any inspection required by paragraph (j) of this AD, thereafter, repeat the inspections specified in paragraph (j) of this AD at intervals not to exceed 9 months, until the actions required by paragraph (m) or (p) of this AD have been accomplished.

(m) Retained Rework

This paragraph restates the rework required by paragraph (c) of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002). For airplanes subject to the requirements of paragraph (j) of this AD: At the applicable time specified in paragraph (m)(1) or (m)(2) of this AD, accomplish rework of the flap track assembly and aft flap track attachments (including removal of the flap track; a detailed visual inspection for a missing, damaged, or migrated anti-fret strip and tapered shim of the rear spar attachments of the flap track; replacement of the anti-fret strip with a new aluminum anti-fret strip (or installation of an aluminum strip if no strip is installed), as applicable; replacement of the tapered shim with a new shim (or installation of a shim if no shim is installed); eddy current and ultrasonic inspections for fatigue cracking of the flap tracks; a detailed visual inspection for corrosion of the flap tracks; and rework of attachment holes), including replacement of the flap tracks, as applicable, by accomplishing all actions specified in Part II of the Accomplishment Instructions of Boeing Service Bulletin 737-57A1249, Revision 1, including Appendix A, dated June 1, 2000. Do these actions according to the Accomplishment Instructions of Boeing Service Bulletin 737-57A1249, Revision 1, including Appendix A, dated June 1, 2000, except as provided by paragraph (o) of this AD. Accomplishment of the actions required by this paragraph terminates the repetitive inspections required by paragraph (l) of this AD. Accomplishing the requirements of paragraph (p) of this AD terminates the requirements of this paragraph.

(1) If no discrepancy is found during any inspection required by paragraph (j) or (l) of this AD: Do the rework within 24 months after April 22, 2002 (the effective date of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002).

(2) If any discrepancy is found during any inspection required by paragraph (j) or (l) of this AD: Do the rework prior to further flight.

(n) Retained Repetitive Inspections

This paragraph restates the repetitive inspections required by paragraph (d) of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002). For Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, except airplanes on which any replacement flap tracks were installed as specified in Boeing Service Bulletin 737-57-1203, dated November 15, 1990, or production equivalent: At the applicable time specified in paragraph (n)(1) or (n)(2) of this AD, and thereafter at least every 24 months, perform detailed visual, HFEC, and ultrasonic inspections for cracking in the upper flange of the inboard track of each outboard flap at the rear spar attachments, according to Part I of the Accomplishment Instructions of Boeing Service Bulletin 737-57A1249, Revision 1, including Appendix A, dated June 1, 2000. Accomplishing the requirements of paragraph (p) of this AD terminates the requirements of this paragraph.

(1) For airplanes subject to paragraph (m) of this AD, do the inspections within 10 years after accomplishment of the rework according to paragraph (m) of this AD.

(2) For airplanes other than those identified in paragraph (n)(1) of this AD, do the inspections within 10 years since the airplane's date of manufacture, or within 6 months after April 22, 2002 (the effective date of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002), whichever occurs later.

(o) Retained Repair Instructions and Exception to Procedures in Service Information

This paragraph restates the repair instructions and exception to procedures required by paragraph (e) of AD 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002). If any discrepancy is found during any action required by paragraph (j), (l), or (m) of this AD, and Boeing Service Bulletin 737-57A1249, Revision 1, including Appendix A, dated June 1, 2000, specifies to contact Boeing for appropriate action; or if any discrepancy is found during inspections according to paragraph (n) of this AD: Prior to further flight, repair according to a method approved by the Manager, Seattle ACO, FAA; or according to data meeting the type certification basis of the airplane approved by a Boeing Company DER or ODA who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the ODA, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the approval letter must specifically reference this AD.

(p) New Inspection of Flap Track Web and Flanges

For all airplanes: At the times specified in paragraph (q) of this AD: Do the inspections specified in paragraphs (p)(1), (p)(2), (p)(3), and (p)(4) of this AD, and do all applicable corrective actions, in accordance with paragraph 3.B.3. of the Accomplishment Instructions of Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, except as required by paragraphs (r) and (v) of this AD. Performing these inspections terminates the requirements of paragraphs (g), (j) and (n) of this AD. Do all applicable corrective actions before further flight.

(1) Detailed inspection for damage (cracks, nicks, corrosion pits, galling, pieces broken off) and stop-drill repairs along the full length of the upper and lower flanges of the flap track.

(2) Detailed inspection for damage, cracking, and stop-drill repairs along the full length of the track webs.

(3) Eddy current inspection for damage (including cracking) of the flap track web and flanges.

(4) Inspection to determine the part number of the flap track assembly.

(q) New Compliance Time

At the latest of the applicable times specified in paragraphs (q)(1), (q)(2), and (q)(3) of this AD, do the actions required by paragraph (p) of this AD.

(1) Within 96 months since the flap track was new or overhauled, or prior to the accumulation of 15,000 flight cycles on the flap track since new or overhauled; whichever occurs first.

(2) Within 180 days after the effective date of this AD.

(3) Within 24 months after the most recent inspection was performed in accordance with Part 1 of the Accomplishment Instructions of Boeing Service Bulletin 737-57A1249, including Appendix A, dated December 16, 1999; or Revision 1, including appendix A, dated June 1, 2000.

(r) Replacement

If, during any inspection required by paragraph (p) of this AD, any flap track assembly having P/N 65-46428-31 or 65-46428-33 is found, before further flight, replace the flap track assembly with a new or serviceable flap track assembly, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, except as required by paragraph (v) of this AD.

(s) New Inspections of Flap-to-Wing Attachment if Repairs Are Done or if No Damage Is Found in Flap Track Web and Flanges

For airplanes on which no damage is found in the flanges or the Web during any inspection required by paragraph (p) of this AD; and for airplanes on which a repair is done during any corrective action required by (p) of this AD; before further flight, do the inspections specified in paragraphs (s)(1) through (s)(4) of this AD, and do all applicable related investigative and corrective actions, in accordance with paragraphs 3.B.4 and 3.B.5 of the Accomplishment Instructions of Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, except as required by paragraph (v) of this AD. If, during the inspection required by paragraph (s)(1) of this AD, an anti-fret strip is not found installed, before further flight, do the related investigative actions specified in Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, for an anti-fret strip that has signs of damage or corrosion and do all applicable corrective actions, including making and installing a new anti-fret strip, in accordance with paragraph 3.B.5 of the Accomplishment Instructions of Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, except as required by paragraph (v) of this AD. Do all applicable related investigative and corrective actions before further flight.

(1) Detailed inspection for signs of movement between the tapered shim and anti-fret strip, installation of the anti-fret strip, and corrosion of the tapered shim and anti-fret strip.

(2) Detailed inspection for signs of movement, cracks and corrosion of the area where the track is attached to the wing rear spar.

(3) High frequency eddy current inspection for cracking of the outboard edge of the track adjacent to the outboard attach bolt.

(4) Ultrasonic inspection for cracking of the inner edge of the track adjacent to the outboard attach bolt.

(t) New Overhaul

Within 10,000 flight cycles on the flap track or 48 months, whichever occurs first after accomplishing the inspection required by paragraph (p) of this AD: Do an overhaul of the flap track, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, except as required by paragraph (v) of this AD. Repeat the overhaul thereafter at intervals not to exceed 20,000 flight cycles on the flap track or 96 months, whichever occurs first.

(u) New Post Overhaul Inspections

For airplanes on which any overhaul required by paragraph (t) of this AD is done: Do the inspections specified in paragraph (p) of this AD within 10,000 flight cycles on the flap track or 48 months after the most recent overhaul, whichever occurs first. Repeat the inspections specified in paragraph (p) of this AD thereafter at intervals not to exceed 10,000 flight cycles on the flap track or 48 months, whichever occurs first; except if an overhaul required by paragraph (t) of this AD is done, do the next inspection within 10,000 flight cycles or 48 months, whichever occurs first, after the overhaul.

(v) Service Information Exception

Where Boeing Service Bulletin 737-57A1271, Revision 3, dated February 13, 2012, specifies to contact Boeing for appropriate action: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (y) of this AD.

(w) New Parts Installation Prohibition

As of the effective date of this AD, no person may install a flap track assembly, P/N 65-46428-31 or 65-46428-33, on any airplane.

(x) Credit for Previous Actions

This paragraph provides credit for the actions specified in paragraphs (p) through (t) of this AD, if those actions were performed before the effective date of this AD, using the service bulletins specified in paragraph (x)(1), (x)(2), or (x)(3) of this AD.

(1) Boeing Alert Service Bulletin 737-57A1271, dated September 11, 2003, which is not incorporated by reference.

(2) Boeing Service Bulletin 737-57A1217, Revision 1, dated July 30, 2008, which is not incorporated by reference.

(3) Boeing Service Bulletin 737-51A1217, Revision 2, dated January 17, 2011, which is not incorporated by reference.

(y) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Seattle 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 emailed to: [e-mail].

(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.

(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 The Boeing Commercial Airplanes ODA that 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.

(4) AMOCs approved previously in accordance with ADs 2000-25-07, Amendment 39-12041 (65 FR 78913, December 18, 2000); and 2002-05-07, Amendment 39-12675 (67 FR 11891, March 18, 2002); are approved as AMOCs for the corresponding requirements of this AD.

(z) Related Information

(1) For more information about this AD, contact Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue SW., Renton, WA 98057-3356; phone: [phone]; fax: [phone]; email: [e-mail].

(2) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, WA 98124-2207; telephone [phone], extension 1; fax [phone]; 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, WA. For information on the availability of this material at the FAA, call 425-227-1221.

Issued in Renton, Washington, on September 27, 2012.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.