2015-20372. Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

We are superseding Airworthiness Directive (AD) 2011-08-51 for certain The Boeing Company Model 737-300, -400, and -500 series airplanes. AD 2011-08-51 required repetitive inspections of the lap joint at certain stringers along the entire length from certain body stations. This new AD expands the inspection area, requires additional inspections for cracks and open pockets, requires corrective actions if necessary, and revises the compliance times. This AD was prompted by an evaluation by the design approval holder (DAH) that has determined that the lower fastener holes in the lower skin of the fuselage lap splice are subject to widespread fatigue damage (WFD). We are issuing this AD to detect and correct fatigue cracking of the lower fastener holes in the lower skin of the fuselage lap splice, which could result in reduced structural integrity of the airplane.

DATES:

This AD is effective September 29, 2015.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of September 29, 2015.

ADDRESSES:

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 view this 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. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA 2014-0772.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2014-0772; 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 (phone: [phone]) is Docket 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:

Jennifer Tsakoumakis, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office (ACO), 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: [phone]; fax: [phone]; email: [e-mail].

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2011-08-51, Amendment 39-16701 (76 FR 28632, May 18, 2011). AD 2011-08-51 applied to certain The Boeing Company Model 737-300, -400, and -500 series airplanes. The NPRM published in the Federal Register on November 17, 2014 (79 FR 68381). The NPRM was prompted by an evaluation by the DAH that has determined that the lower fastener holes in the lower skin of the fuselage lap splice are subject to WFD. The NPRM proposed to continue to require repetitive inspections of the lap joint at certain stringers along the entire length from certain body stations. The NPRM also proposed to expand the inspection area, require additional inspections for cracks and open pockets, require corrective actions if necessary, and revise the compliance times. We are issuing this AD to detect and correct fatigue cracking of the lower fastener holes in the lower skin of the fuselage lap splice, which could result in reduced structural integrity of the airplane.

Comments

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the NPRM (79 FR 68381, November 17, 2014) and the FAA's response to each comment.

Request To Revise Wording

Boeing requested that we revise the last sentence in paragraph (k) of the proposed AD (79 FR 68381, November 17, 2014) to clarify that the on-condition actions may be “inspection or repair” rather than “inspection and repair.” Boeing stated that condition 10 in table 6 of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, describes obtaining inspection or repair instructions. Boeing explained that, depending on the configuration details identified, repetitive inspections alone may be an appropriate action, or a repair may be the appropriate action.

We agree with the commenter's request. Varying detail configurations and the total flight cycles at the time of the finding are used to determine if an inspection program is adequate to address the unsafe condition or if installation of a repair is required. We have revised the wording in paragraph (k) of this AD to require inspection or repair.

Request To Clarify Paragraph Heading

Southwest Airlines (SWA) stated that the heading “Repetitive Inspections for Crack Indications at Stringers S-4R and S-4L, Body Station (BS) 360 to BS 908,” of paragraph (g) of the proposed AD (79 FR 68381, November 17, 2014) is misleading. SWA explained that the heading is confusing since the paragraph contains both an initial inspection and repetitive inspections.

We agree to clarify the terminology used in the heading. When the term “repetitive” is used, it does not necessarily exclude the initial action. Many existing ADs use the term “repetitive” in the headers for paragraphs that contain both the initial action and repetitive actions. We find that no change to this AD is necessary regarding this issue.

Request To Add Clarifying Note

SWA requested that we add a note in paragraph (g) and paragraph (h) of the proposed AD (79 FR 68381, November 17, 2014) specifying that Group 3 airplanes do not require inspection between BS 540 and BS 727E. SWA stated that Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, specifies no inspections to be accomplished from BS 540 to BS 727E on Group 3 airplanes. SWA stated that, since paragraphs (g) and (h) of the proposed AD and tables 1, 2, and 3 of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, define the inspection area as stringers 4L and 4R from BS 360 to BS 908 for all airplanes, it could be interpreted that the proposed AD would require an increased inspection area for Group 3 airplanes.

We partially agree with the commenter's request. We disagree to add a note in paragraph (g) and paragraph (h) of this AD. The Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, are clear regarding which areas must be inspected. The SUMMARY section of this final rule does specify that the inspection area is increased. However, we have added “as applicable” to paragraphs (g) and paragraph (h) of this AD to provide clarification regarding the inspection area.

Request To Clarify Compliance Times

SWA requested that we revise paragraph (g) of the proposed AD (79 FR 68381, November 17, 2014) to clarify the compliance times. SWA recommended splitting the paragraph requirements into three separate paragraphs to address three different airplane groups. SWA stated that table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, does not account for airplanes that were inspected previously using either Boeing Alert Service Bulletin 737-53A1319, dated April 4, 2011, or Boeing Alert Service Bulletin 737-53A1319, Revision 1, dated April 8, 2011. SWA stated that it is unclear how to apply the compliance times in table 1 for these airplanes, and as a result, airplanes with more than 30,000 total flight cycles that were not inspected previously using Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, will have exceeded the compliance times in table 1 upon the effective date of the AD.

SWA stated that since paragraph (n) of the proposed AD (79 FR 68381, November 17, 2014) provides credit for actions required by paragraph (g) of the proposed AD that were performed prior to the effective date of the AD using either Boeing Alert Service Bulletin 737-53A1319, dated April 4, 2011, or Boeing Alert Service Bulletin 737-53A1319, Revision 1, dated April 8, 2011, SWA assumes that the intent of paragraph (g) of the proposed AD is for the operator to accomplish the first inspection in accordance with Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, within 500 cycles from the last inspection accomplished previously in accordance with either the Boeing Alert Service Bulletin, dated April 4, 2011, or Revision 1, dated April 8, 2011.

We do not agree with the commenter's request to revise paragraph (g) of this AD. However, we do agree to clarify the compliance times. For airplanes that were inspected previously using either Boeing Alert Service Bulletin 737-53A1319, dated April 4, 2011, or Boeing Alert Service Bulletin 737-53A1319, Revision 1, dated April 8, 2011, the next inspection must be done within 500 cycles from the last inspection accomplished previously in accordance with either the Boeing Alert Service Bulletin, dated April 4, 2011, or Revision 1, dated April 8, 2011, except as provided by table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014. Table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, provides optional inspections that may be used after inspections in table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, have been accomplished.

For airplanes that were not inspected previously using either Boeing Alert Service Bulletin 737-53A1319, dated April 4, 2011, or Boeing Alert Service Bulletin 737-53A1319, Revision 1, dated April 8, 2011, the initial inspection must be done within the applicable compliance times specified in table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014. We have not changed this AD in this regard.

Request To Clarify Inspection Requirements

SWA requested that we provide clarification regarding the applicability of table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, for accomplishing the repetitive inspections required by paragraph (g) of the proposed AD (79 FR 68381, November 17, 2014). SWA stated that the inspection intervals defined in table 2 are dependent on the total flight cycles of airplanes that meet condition 1 (no crack found), and that operators of airplanes that meet condition 2 (any crack found) should contact Boeing for repair instructions prior to further flight.

SWA stated that the alternative repetitive inspection intervals apply only to aircraft that meet condition 1 each time the aircraft is inspected. SWA explained that it is unclear whether or not the operator is able to continue utilizing the table 2 inspection intervals if condition 2 is found during any repetitive inspection on an airplane, or if the operator must revert back to the table 1 repetitive inspection interval from that point forward for that airplane.

We agree that clarification is necessary. Paragraph (l) of this AD requires a repair if any crack is found. Accomplishment of the repair terminates the repetitive inspections required by paragraphs (g) and (j) of this AD in the repaired area only. Repetitive inspections must be done on all unrepaired areas at the times specified in table 1 or table 2, as applicable. We find that no change to this AD is necessary regarding this issue.

Requests for Credit and Exception to Inspection Requirements

SWA requested that we include a provision in paragraph (n) of the proposed AD (79 FR 68381, November 17, 2014) to provide credit for the general visual inspection required by paragraph (k) of the proposed AD for skin panels that were replaced using the procedures specified in Figure 35 of Boeing Service Bulletin 737-53-1306, provided that the corrective action for Condition 9 is followed.

SWA also requested that we add an exception in paragraph (m) of the proposed AD (79 FR 68381, November 17, 2014) that allows the operator to omit the inspection required by paragraph (k) of the proposed AD if the corrective action for Condition 9 is followed and the operator's records show the part number of the skin assembly installed on the airplane.

To justify its requests, SWA stated that its airplanes, defined as Group 1 in Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, on which the crown skin panel replacement was accomplished as described previously in Figure 35 of Boeing Service Bulletin 737-53-1306, were inspected previously to determine if the existing skin assembly was an “MPN 65C35798-1 (open pockets adjacent to the STR 4R lap joint)” or an “MPN 65C35798-8 (closed pockets adjacent to the STR 4R lap joint).” SWA stated that the existing skin panel was then replaced with a new skin panel of the same configuration as the removed production panel. SWA explained that if an operator's records show the part number of the skin panel assembly installed, the operator will be able to determine if the panel is configured with Condition 9 or Condition 10 and, therefore, SWA does not need to do the inspection required by paragraph (k) of the proposed AD.

We disagree with the commenter's requests. The fuselage crown skin replacements described in Boeing Service Bulletin 737-53-1306 are a part of a SWA-specific modification program. We do not consider it appropriate to include various provisions in an AD that are applicable only to a single operator's unique use of an affected airplane. However, an operator may request approval of an alternative method of compliance under the provisions of paragraph (o) of this AD if sufficient data are submitted to substantiate that the fuselage crown skin replacements would provide an acceptable level of safety. We have not changed this AD in this regard.

Conclusion

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD with the changes described previously and minor editorial changes. We have determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM (79 FR 68381, November 17, 2014) for correcting the unsafe condition; and
• Do not add any additional burden upon the public than was already proposed in the NPRM (79 FR 68381, November 17, 2014).

We also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD.

Interim Action

We consider this AD interim action. An investigation is ongoing, and no terminating action has been developed. Once terminating action is developed, approved, and available, we might consider additional rulemaking.

Related Service Information Under 1 CFR Part 51

We reviewed Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014. The service information describes procedures for inspections for crack indications at certain stringers, an inspection for open pockets of the lower skin panel at stringer S-4R, and repairs. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section of this AD.

Costs of Compliance

We estimate that this AD affects 130 airplanes of U.S. registry.

We estimate the following costs to comply with this AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
Repetitive inspections [actions retained from AD 2011-08-51, Amendment 39-16701 (76 FR 28632, May 18, 2011)]	6 or 4,270 work-hours (depending on inspection method) × $85 per work-hour = $510 or $362,950 per inspection cycle	None	$510 or $362,950 per inspection cycle	$66,300 or $47,183,500 per inspection cycle.
Repetitive inspections [new action]	4 or 550 work-hours (depending on inspection method) × $85 per hour = $340 or $46,750 per inspection cycle	None	$340 or $46,750 per inspection cycle	$44,200 or $6,077,500 per inspection cycle.
One-time inspections [new action]	5,370 work-hours × $85 per hour = $456,450	None	$456,450	$59,338,500.

We have received no definitive data that would enable us to provide a cost estimate for the on-condition actions specified in this 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 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),

(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

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 removing Airworthiness Directive (AD) 2011-08-51, Amendment 39-16701 ( 76 FR 28632, May 18, 2011), and adding the following new AD:

2015-16-08 The Boeing Company: Amendment 39-18233; Docket No. FAA-2014-0772; Directorate Identifier 2014-NM-090-AD.

(a) Effective Date

This AD is effective September 29, 2015.

(b) Affected ADs

This AD replaces AD 2011-08-51, Amendment 39-16701 (76 FR 28632, May 18, 2011).

(c) Applicability

This AD applies to The Boeing Company Model 737-300, -400, and -500 series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014.

(d) Subject

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

(e) Unsafe Condition

This AD was prompted by an evaluation by the design approval holder (DAH) that has determined that the lower fastener holes in the lower skin of the fuselage lap splice are subject to widespread fatigue damage (WFD). We are issuing this AD to detect and correct fatigue cracking of the lower fastener holes in the lower skin of the fuselage lap splice, which could result in reduced structural integrity of the airplane.

(f) Compliance

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

(g) Repetitive Inspections for Crack Indications at Stringers S-4R and S-4L, Body Station (BS) 360 to BS 908

At the applicable time specified in table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014: Do an external eddy current inspection, or internal eddy current and detailed inspections, for crack indications at stringers S-4R and S-4L, from BS 360 to BS 908, as applicable, except as provided by paragraph (h) of this AD, in accordance with Part 1 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014. Repeat the inspection(s) thereafter at the applicable intervals specified in table 1 or table 2, as applicable, of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014. Either inspection option may be used at any repetitive inspection cycle.

(h) One-Time Inspections for Cracks at Stringers S-4L and S-4R, BS 360 to BS 908

At the applicable time specified in table 3 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, except as required by paragraph (m) of this AD: Do one-time internal detailed and eddy current inspections for cracks at stringers S-4R and S-4L, from BS 360 to BS 908, as applicable, in accordance with Part 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014. Accomplishment of the inspections required by this paragraph does not terminate the repetitive inspections required by paragraph (g) of this AD.

(i) One-Time Inspections for Cracks at Stringer S-4R, BS 908 to BS 1016

For airplanes identified as Group 2, 3, 5, and 7 in Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014: At the applicable time specified in table 4 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, except as required by paragraph (m) of this AD, do one-time internal detailed and eddy current inspections for cracks at stringer S-4R, from BS 908 to BS 1016, in accordance with Part 3 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014.

(j) Repetitive Inspections for Cracks at Stringer S-4R, BS 908 to BS 1016

For airplanes identified as Group 2, 3, 5, and 7 in Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014: At the applicable time specified in table 5 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, except as required by paragraph (m) of this AD, do external eddy current inspections, or internal eddy current and detailed inspections, for cracks at stringer S-4R, from BS 908 to BS 1016, in accordance with Part 4 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014. Repeat the inspection(s) thereafter at the applicable intervals specified in table 5 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014. Either inspection option may be used at any repetitive inspection cycle.

(k) General Visual Inspection for Open Pockets at Stringer S-4R, BS 908 to BS 1016

For airplanes identified as Group 1, 4, and 6 in Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014: At the applicable time specified in table 6 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, except as required by paragraph (m) of this AD, do a general visual inspection for open pockets of the lower skin panel at stringer S-4R, from BS 908 to BS 1016, in accordance with Part 5 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014. If any open pocket is found, before further flight, inspect or repair using a method approved in accordance with the procedures specified in paragraph (o) of this AD.

(l) Corrective Action

If any crack is found during any inspection required by this AD: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (o) of this AD. Accomplishment of repairs approved in accordance with the procedures specified in paragraph (o) of this AD terminates the repetitive inspections specified in paragraphs (g) and (j) of this AD in the repaired areas only.

(m) Service Information Exception

Where Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014, specifies a compliance time “after the Revision 2 date of this service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD.

(n) Credit for Previous Actions

This paragraph provides credit for actions required by paragraph (g) of this AD, if those actions were performed before the effective date of this AD using Boeing Alert Service Bulletin 737-53A1319, dated April 4, 2011; or Boeing Alert Service Bulletin 737-53A1319, Revision 1, dated April 8, 2011. Boeing Alert Service Bulletin 737-53A1319, dated April 4, 2011, was incorporated by reference in AD 2011-08-51, Amendment 39-16701 (76 FR 28632, May 18, 2011). Boeing Alert Service Bulletin 737-53A1319, Revision 1, dated April 8, is not incorporated by reference in this AD.

(o) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Los Angeles Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. 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 paragraph (p)(1) of this AD.

(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, Los Angeles 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 for AD 2011-08-51, Amendment 39-16701 (76 FR 28632, May 18, 2011), are approved as AMOCs for the corresponding provisions of paragraphs (g) and (l) of this AD.

(p) Related Information

(1) For more information about this AD, contact Jennifer Tsakoumakis, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office (ACO), 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: [phone]; fax: [phone]; email: [e-mail].

(2) Service information identified in this AD that is not incorporated by reference is available at the addresses specified in paragraphs (q)(4) and (q)(5) of this AD.

(q) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise.

(3) The following service information was approved for IBR on September 29, 2015.

(i) Boeing Alert Service Bulletin 737-53A1319, Revision 2, dated April 4, 2014.

(ii) Reserved.

(4) For Boeing 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.

(5) You may view this 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.

(6) You may view this 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/​cfr/​ibr-locations.html.

Issued in Renton, Washington, on August 7, 2015.

Jeffrey E. Duven,

Manager, Transport Airplane Directorate, Aircraft Certification Service.