2013-15694. Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

We propose to supersede three existing airworthiness directives (ADs) that apply to The Boeing Company Model 757-200, -200PF, and -200CB series airplanes. The existing ADs currently require repetitive inspections and audible tap tests of the upper and lower skins of the trailing edge wedges on certain slats, and related investigative and corrective actions if necessary. Since we issued these ADs, we have received reports of slats disbonding on airplanes on which the terminating actions of the existing ADs were completed and also reports of slats disbonding on airplanes outside of the applicability of the existing ADs. This proposed AD would require a determination of the type of trailing edge wedges of the leading edge slats, repetitive inspections on certain trailing edge wedges for areas of skin-to-core disbonding, and corrective actions if necessary. This proposed AD would also provide an optional terminating action for the repetitive inspections. This AD would revise the applicability of the existing ADs to include additional airplanes. We are proposing this AD to prevent delamination of the trailing edge wedge of the leading edge slats, possible loss of pieces of the trailing edge wedge assembly during flight, reduction of the reduced maneuver and stall margins, and consequent reduced controllability of the airplane.

DATES:

We must receive comments on this proposed AD by August 16, 2013.

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 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, Washington. 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, Seattle Aircraft Certification Office (ACO), FAA, 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-2013-0541; Directorate Identifier 2011-NM-097-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 October 23, 1990, we issued AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990), for certain Boeing Model 757 series airplanes, which requires close visual inspections of the trailing edge wedges on the leading edge slats to detect delamination and physical damage, and replacement or repair of defective parts if necessary.

On December 18, 1991, we issued AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992), for certain Boeing Model 757 series airplanes, which requires repetitive inspections to detect delamination of or physical damage to the trailing edge wedges on the leading edge wing slats, and repair if necessary.

On March 22, 2005, we issued AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005), for certain Boeing Model 757-200 and -200PF series airplanes, which requires repetitive inspections and audible tap tests of the upper and lower skins of the trailing edge wedges on certain slats, and related investigative and corrective actions if necessary. This AD also provides an optional terminating action for the repetitive inspections and audible tap tests, which consists of replacing the trailing edge wedge assemblies with new, improved wedge assemblies.

Those ADs resulted from multiple reports of damage to the leading edge slats. We issued those ADs to prevent delamination of the leading edge slats, possible loss of pieces of the trailing edge wedge assembly during flight, reduction of the reduced maneuver and stall margins, and consequent reduced controllability of the airplane.

Actions Since Existing ADs Were Issued

Since we issued AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005), we have received reports of slat disbonding on airplanes on which the optional terminating action of AD 2005-07-08 was completed, and also reports of slats disbonding on airplanes outside of the applicability of the existing ADs. Additionally, the manufacturer has developed a new terminating action, which, when accomplished, terminates the repetitive inspections of AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990); AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992); and AD 2005-07-08.

Relevant Service Information

We reviewed Boeing Special Attention Service Bulletin 757-57-0066, dated April 5, 2011. For information on the procedures and compliance times, see this service information at http://www.regulations.gov by searching for Docket No. FAA-2013-0541.

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 the same type design.

Proposed AD Requirements

This proposed AD would retain all requirements of AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990); AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992); and AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005). This proposed AD would add airplanes to the applicability statement. This proposed AD would also require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and the Service Information.” Accomplishment of the new initial proposed inspection and applicable corrective actions would terminate the existing requirements.

The phrase “related investigative actions” might be used in this proposed AD. “Related investigative actions” are follow-on actions that: (1) Are related to the primary actions, and (2) are actions that further investigate the nature of any condition found. Related investigative actions in an AD could include, for example, inspections.

In addition, the phrase “corrective actions” might be used in this proposed AD. “Corrective actions” are actions that correct or address any condition found. Corrective actions in an AD could include, for example, repairs.

Change to Existing AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990)

This proposed AD would retain all the requirements of AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990). Since AD 90-23-06 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Revised Paragraph Identifiers

Requirement in AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990)	Corresponding requirement in this proposed AD
paragraph (A)	paragraph (g)(1).
paragraph (B)	paragraph (g)(2).
paragraph (C)	paragraph (g)(3).
paragraph (D)	paragraph (h).

Change to Existing AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992)

The corresponding paragraph identifiers also have been changed for AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992), and are listed in the following table:

Revised Paragraph Identifiers

Requirement in AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992)	Corresponding requirement in this proposed AD
paragraph (a)	paragraph (i)(1).
paragraph (a)(1)	paragraph (i)(1)(i).
paragraph (a)(2)	paragraph (i)(1)(ii).
paragraph (b)	paragraph (i)(2).
paragraph (c)	paragraph (j).

Change to Existing AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005)

This proposed AD also would retain all the requirements of AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005). Since AD 2005-07-08 was issued, the AD format has been revised, and certain paragraphs have been rearranged. As a result, the corresponding paragraph identifiers have changed in this proposed AD, as listed in the following table:

Revised Paragraph Identifiers

Requirement in AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005)	Corresponding requirement in this proposed AD
paragraph (f)	paragraph (k).
paragraph (g)	paragraph (l).
paragraph (h)	paragraph (m).
paragraph (i)	paragraph (n).
paragraph (j)	paragraph (o).

Differences Between the Proposed AD and the Service Information

Boeing Special Attention Service Bulletin 757-57-0066, dated April 5, 2011, specifies to contact the manufacturer for instructions on how to repair certain conditions, but this proposed AD would require repairing those conditions in one of the following ways:

• In accordance with a method that we approve; or
• Using data that meet the certification basis of the airplane, and that have been approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) whom we have authorized to make those findings.

Costs of Compliance

We estimate that this proposed AD affects 640 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	Cost on U.S. operators
Inspection/test [retained actions from existing ADs]	6 work-hours × $85 per hour = $510 per inspection cycle	$0	$510 per inspection cycle	$326,400 per inspection cycle.
Inspection/test [new proposed action]	Up to 20 work-hours × $85 per hour = $1,700 per inspection cycle	0	Up to $1,700 per inspection cycle	Up to $1,088,000 per inspection cycle.

We have received no definitive data that would enable us to provide cost estimates for the on-condition actions specified in this proposed AD.

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 directive (AD) 90-23-06, Amendment 39-6794 ( 55 FR 46499, November 5, 1990); AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992); and AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005), and adding the following new AD:

The Boeing Company: Docket No. FAA-2013-0541; Directorate Identifier 2011-NM-097-AD.

(a) Comments Due Date

The FAA must receive comments on this AD action by August 16, 2013.

(b) Affected ADs

This AD supersedes AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005); AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992); and AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990).

(c) Applicability

This AD applies to all The Boeing Company Model 757-200, -200PF, and -200CB 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 of slat disbonding on airplanes that had performed the terminating actions of an AD; and we have received reports of slats disbonding on airplanes outside of the applicability of the existing ADs. We are issuing this AD to prevent delamination of the trailing edge wedge of the leading edge slats, possible loss of pieces of the trailing edge wedge assembly during flight, reduction of the reduced maneuver and stall margins, 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 of Trailing Edge Wedges

This paragraph restates the requirements of paragraphs A., B., and C. of AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990).

(1) For Model 757 series airplanes, line numbers 001 through 091: Prior to the accumulation of 11,000 flight hours, or within the next 10 calendar days after September 21, 1990 (the effective date of telegraphic AD T90-20-51), whichever occurs later, perform a close detailed visual inspection of the trailing edge wedges on all the leading edge slats for delamination and physical damage, in accordance with Boeing Alert Service Bulletin 757-57A0038, dated September 21, 1990; Boeing Alert Service Bulletin 757-57A0038, Revision 1, dated September 25, 1990; or Boeing Alert Service Bulletin 757-57A0038, Revision 2, dated October 10, 1990.

Note 1 to paragraph (g)(1) of this AD:

Telegraphic AD T90-20-51 was sent directly to owners and operators of the affected airplanes on September 21, 1990. AD T90-20-51 was not published in the Federal Register, because it was promptly superseded by AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990).

(2) For Model 757 series airplanes, line numbers 092 through 158: Prior to the accumulation of 11,000 flight hours, or within the next 10 calendar days after November 19, 1990 (the effective date of AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990)), whichever occurs later, perform a close detailed visual inspection of the trailing edge wedges on all the leading edge slats for delamination and physical damage, in accordance with Boeing Alert Service Bulletin 757-57A0038, dated September 21, 1990; Boeing Alert Service Bulletin 757-57A0038, Revision 1, dated September 25, 1990; or Boeing Alert Service Bulletin 757-57A0038, Revision 2, dated October 10, 1990.

(3) Repeat the inspections required by paragraph (g)(1) or (g)(2) of this AD, as applicable, at intervals not to exceed 300 flight hours. Doing the initial inspection and applicable corrective actions required by paragraph (p) of this AD terminates the requirements of paragraph (g) of this AD.

(h) Retained Repair or Replacement for Paragraph (g) of This AD

This paragraph restates the repair or replacement required by paragraph D. of AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990). If delamination and/or physical damage are found during any inspection required by paragraph (g) of this AD, prior to further flight, repair using a method approved in accordance with the procedures specified in paragraph (u) of this AD or replace with new parts. Doing the initial inspection and applicable corrective actions required by paragraph (p) of this AD terminates the requirements of paragraph (h) of this AD.

(i) Retained Repetitive Inspections for Certain Airplanes

This paragraph restates the repetitive inspections required by paragraphs (a) and (b) of AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992). For Model 757 series airplanes, line numbers 140 through 335, accomplish the following:

(1) Perform a close detailed visual inspection of the trailing edge wedges of slats 1 through 4 and 7 through 10, for delamination and physical damage, in accordance with Boeing Alert Service Bulletin 757-57A0045, dated October 16, 1991, at the times specified below, until the initial inspection and applicable corrective actions required by paragraph (p) of this AD are accomplished.

(i) For airplanes that have accumulated 5,000 or more flight hours as of January 24, 1992 (the effective date AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992)): Within the next 10 calendar days after January 24, 1992, and thereafter at intervals not to exceed 300 flight hours.

(ii) For airplanes that have accumulated less than 5,000 flight hours as of January 24, 1992 (the effective date AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992)): Within the next 300 flight hours after January 24, 1992, and thereafter at intervals not to exceed 300 flight hours.

(2) Within the next 300 flight hours after January 24, 1992 (the effective date of AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992), perform a “coin-tap” inspection of the trailing edge wedges of slats 1 through 4 and 7 through 10 for delamination and physical damage, in accordance with Boeing Alert Service Bulletin 757-57A0045, dated October 16, 1991. Repeat this inspection at intervals not to exceed 1,500 flight hours.

(j) Retained Repair or Replacement for Paragraph (i) of This AD

This paragraph restates the repair or replacement required by paragraph (c) of AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992). If delamination and/or physical damage are found as a result of the inspections required by paragraph (i)(1) or (i)(2) of this AD, prior to further flight, repair using a method approved in accordance with the procedures specified in paragraph (u) of this AD or replace with new parts. If a repair is accomplished or if new parts are installed, the inspections required by paragraphs (i)(1) and (i)(2) of this AD must be continued. Doing the initial inspection and applicable corrective actions in paragraph (p) of this AD terminates the requirements of paragraphs (i) and (j) of this AD.

(k) Retained Repetitive Inspections and Tests

This paragraph restates the repetitive inspections and tests required by paragraph (f) of AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005).

(1) For Model 757-200 and -200PF series airplanes identified in Boeing Alert Service Bulletin 757-57A0063, dated June 26, 2003: Within 18 months after May 5, 2005 (the effective date of AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005)), do a detailed inspection and an audible tap test of the upper and lower skins of the trailing edge wedges on slats No. 2 through No. 4 inclusive and No. 7 through No. 9 inclusive, for evidence of damage or cracking, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 757-57A0063, dated June 26, 2003. Repeat the detailed inspection and audible tap test thereafter at intervals not to exceed 18 months. Doing the initial inspection and applicable corrective actions in paragraph (p) of this AD terminates the requirements of paragraph (k) of this AD.

(2) For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, 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. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”

(l) Retained Related Investigative and Corrective Actions

This paragraph restates the related investigative and corrective actions required by paragraph (g) of AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005). If any damage or cracking is found during any inspection or audible tap test required by paragraph (k) of this AD: Before further flight, do the related investigative action, if applicable, and replace the affected part with a new trailing edge wedge assembly or repair the affected part, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 757-57A0063, dated June 26, 2003. Accomplishing the replacement terminates the repetitive inspections and audible tap tests required by paragraph (k) of this AD for that wedge assembly only. Doing the initial inspection and applicable corrective actions in paragraph (p) of this AD terminates the requirements of paragraph (l) of this AD.

(m) Retained Credit for Previous Actions

This paragraph restates the credit for actions accomplished previously as specified in paragraph (h) of AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005). This paragraph provides credit for the actions required by paragraph (k) of this AD, if those actions were performed before May 5, 2005 (the effective date of AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005)) using all of the actions specified in the Accomplishment Instructions of Boeing Service Bulletin 757-57A0038, Revision 5, dated July 16, 1992; or Boeing Service Bulletin 757-57A0038, Revision 6, dated November 10, 1994; in conjunction with the use of BMS 5-137 adhesive.

(n) Retained Parts Installation Limitations

This paragraph restates the parts installation limitation of paragraph (i) of AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005), with new actions. For Model 757-200 and -200PF series airplanes identified in Boeing Alert Service Bulletin 757-57A0063, dated June 26, 2003: As of May 5, 2005 (the effective date of AD 2005-07-08), no trailing edge wedge assembly having a part number listed in the “Existing Part Number” column of the table in paragraph 2.C.3. of Boeing Alert Service Bulletin 757-57A0063, dated June 26, 2003, may be installed on any airplane, unless it has been inspected, tested, and had any necessary corrective actions accomplished in accordance with paragraphs (k) and (l) of this AD or in accordance with paragraphs (p) and (q) of this AD. As of the effective date of this AD, no part identified in this paragraph may be installed on any airplane unless it has been inspected, tested, and had all applicable corrective actions accomplished in accordance with paragraphs (p) and (q) of this AD.

(o) Retained Optional Terminating Action

This paragraph restates the optional terminating action previously specified in paragraph (j) of AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005). Replacing all trailing edge wedge assemblies with new, improved wedge assemblies (type B) in accordance with Part III of the Accomplishment Instructions of Boeing Alert Service Bulletin 757-57A0063, dated June 26, 2003, terminates the requirements of paragraph (k) of this AD.

(p) New Inspection To Determine Slat Wedge Type

At the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 757-57-0066, dated April 5, 2011, except as specified in paragraph (s) of this AD: Do an inspection of the trailing edge wedges of the leading edge slats, or a review of airplane maintenance records, to determine whether each slat wedge is a type A or a type B, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-57-0066, dated April 5, 2011.

(q) New Type A Slat Wedge Repetitive Inspections and Corrective Actions

For each type A trailing edge slat wedge found during the inspection or records review required by paragraph (p) of this AD: At the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 757-57-0066, dated April 5, 2011, except as specified in paragraph (s) of this AD, do an ultrasonic or tap test inspection for disbonds of each leading edge slat trailing edge wedge, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-57-0066, dated April 5, 2011. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles or 24 months, whichever occurs first.

(1) For any disbond found during any inspection required by paragraph (q) of this AD that is less than or equal to 1.50 inches in maximum dimension, and is located more than or equal to 1.0 inch from the edge of the panel, and is located more than or equal to 4 times the disbond maximum dimension, measured edge to edge, from adjacent damage: Within 600 flight cycles after the disbond was found, do the inspection required by paragraph (q) of this AD of the disbond area, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-57-0066, dated April 5, 2011. Repeat the inspection thereafter at intervals not to exceed 600 flight cycles. Within 3,000 flight cycles after the disbond was found: Repair the disbond, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757-57-0066, dated April 5, 2011: or replace the affected trailing edge slat wedge using a method approved in accordance with the procedures specified in paragraph (u) of this AD.

(2) For any disbond found during any inspection required by paragraph (q) of this AD that is more than 1.50 inches in maximum dimension, or is located less than 1.0 inch from the edge of the panel, or is located less than 4 times the disbond maximum dimension, measured edge to edge, from adjacent damage: Before further flight, repair or replace using a method approved in accordance with the procedures specified in paragraph (u) of this AD.

(r) Repetitive Inspections of Certain Replaced or Repaired Wedges

(1) For any trailing edge slat wedge that is replaced with a type A wedge: Within 3,000 flight cycles after the replacement or within 24 months after the replacement, whichever occurs first, do the actions required by paragraph (q) of this AD on the replaced type A trailing edge slat wedge. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles or 24 months, whichever occurs first.

(2) For any trailing edge type A slat wedge that is repaired: Within 600 flight cycles after the repair, do the actions required by paragraph (q) of this AD on the repaired area. Repeat the inspection thereafter at intervals not to exceed 600 flight cycles.

(s) Exception to Compliance Time

Where Paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 757-57-0066, dated April 5, 2011, specifies a compliance time “after the original issue date of this service bulletin,” this AD requires compliance within the specified compliance time “after the effective date of this AD”.

(t) New Terminating Actions

(1) Doing the initial inspection specified in paragraph (q) of this AD and applicable type A trailing edge slat wedge repair or replacement, in accordance with the actions specified in paragraph (q)(1) or (q)(2) of this AD, terminates the requirements of paragraphs (g), (h), (i), (j), (k), and (l) of this AD.

(2) Replacing a type A wedge with a type B wedge using a method approved in accordance with the procedures specified in paragraph (u) of this AD terminates the repetitive inspections of a type A trailing edge slat wedge of the leading edge required by paragraph (q) of this AD.

(u) 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: 9-ANM-Seattle-ACO-AMOC-Requests-faa.gov.

(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 Organization Designation Authorization (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 the ADs specified in paragraphs (u)(4)(i), (u)(4)(ii), and (u)(4)(iii) of this AD are approved as AMOCs for the corresponding provisions of this AD.

(i) AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990).

(ii) AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992).

(iii) AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005).

(v) Related Information

(1) For more information about this AD, contact Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, Seattle Aircraft Certification Office (ACO), FAA, 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; phone: [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, Washington. For information on the availability of this material at the FAA, call 425-227-1221.

Issued in Renton, Washington, on June 14, 2013.

Jeffrey E. Duven,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.