### 72564 Federal Register / Vol. 78, No. 232 / Tuesday, December 3, 2013 / Rules and Regulations

conditions ‘‘as of the original issue date of this service bulletin.’’ This AD, however, applies to the airplanes with the specified condition as of the effective date of this AD.
(j) Credit for Previous Actions

This paragraph provides credit for the actions required by paragraphs (g) and (h) of this AD, if those actions were performed before the effective date of this AD using Boeing Service Bulletin 747–53A2747, Revision 1, dated October 12, 2011, which is not incorporated by reference in this AD.
(k) Terminating Action for Other ADs

(1) Accomplishing the requirements of this AD terminates the requirements of paragraphs (f), (g), and (h) of AD 2006–20– 02, Amendment 39–14771 (71 FR 56861, September 28, 2006).

(2) Accomplishing the requirements of this AD terminates the requirements of paragraphs (f), (k), and (l) of AD 2006–24–02, Amendment 39–14831 (71 FR 67445, November 22, 2006).

(3) Accomplishing the requirements of this AD terminates the requirements of paragraphs (f) and (i) of AD 2006–24–05, Amendment 39–14834 (71 FR 68434, November 27, 2006).
(l) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Seattle 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 (m)(1) of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-AMOCRequests@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.

(m) Related Information

(1) For more information about this AD, contact Nathan Weigand, Aerospace Engineer, Airframe Branch, ANM–120S, FAA, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue SW., Renton, WA 98057–3356; phone: 425–917–6428; fax: 425– 917–6590; email: Nathan.P.Weigand@ faa.gov.

(2) Service information identified in this AD that is not incorporated by reference in this AD may be obtained at the addresses specified in paragraphs (n)(3) and (n)(4) of this AD. (n) 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.

(i) Boeing Service Bulletin 747–53A2747, Revision 2, dated February 22, 2012.

(ii) Reserved. (3) 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 206–544–5000, extension 1; fax 206–766– 5680; Internet https:// www.myboeingfleet.com.

(4) 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.

(5) 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/ibrlocations.html.

Issued in Renton, WA, on November 15,
2013. Jeffrey E. Duven, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 2013–28611 Filed 12–2–13; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2012–1229; Directorate Identifier 2012–NM–135–AD; Amendment**  **39–17684; AD 2013–24–10]**

**RIN 2120–AA64**

**Airworthiness Directives; The Boeing Company Airplanes** 

**AGENCY :**  Federal Aviation Administration (FAA), DOT.

**ACTION :**  Final rule.

**SUMMARY :**  We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 757 and Model 767 airplanes. This AD was prompted by a standby power relay failure and subsequent illumination of the ‘‘STANDBY BUS OFF’’ light, which led the flightcrew to set the standby power switch to the ‘‘BAT’’ position, isolating the battery and standby buses, disabling the battery charger, and eventually causing the main battery to be depleted. This AD requires doing wiring changes and installing a new air/ ground relay to the battery charger system. We are issuing this AD to prevent discharge of the main battery, which could result in multiple system degradation, reduced airplane controllability, and runway excursion upon landing.

**DATES :**  This AD is effective January 7,
2014.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of January 7, 2014.

**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 206–544–5000, extension 1; fax 206–766–5680; 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. 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 AD, the regulatory evaluation, any comments received, and other information. The address for the Docket Office (phone: 800–647–5527) is Document Management Facility, U.S. Department of Transportation, Docket Operations, M–30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE., Washington, DC 20590.

**FOR FURTHER INFORMATION CONTACT :**  Marie Hogestad, Aerospace Engineer, Systems and Equipment Branch, ANM– 130S, Seattle Aircraft Certification Office (ACO), FAA, 1601 Lind Avenue SW., Renton, WA 98057–3356; phone: 425–917–6418; fax: 425–917–6590; email: marie.hogestad@faa.gov

. **SUPPLEMENTARY INFORMATION :** 

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to the specified products. The NPRM published in the Federal Register on December 20, 2012 (77 FR 75402). The NPRM proposed to require doing wiring changes and installing a


### 72565 Federal Register / Vol. 78, No. 232 / Tuesday, December 3, 2013 / Rules and Regulations

new air/ground relay to the battery charger system.

Comments

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal (77 FR 75402, December 20, 2012) and the FAA’s response to each comment.
Support for the NPRM (77 FR 75402, December 20, 2012)

The Air Line Pilots Association International (ALPA) stated that it supports the NPRM (77 FR 75402, December 20, 2012).

Boeing stated that it concurs with the contents of the NPRM (77 FR 75402, December 20, 2012).

The National Transportation Safety Board stated that it supports the NPRM (77 FR 75402, December 20, 2012), and that, in conjunction with the procedural changes recommended by the board and implemented by Boeing, the NPRM will provide an additional margin of safety by requiring modifications to the airplane that will allow flightcrews to manage the electrical system more effectively in the event of a relay failure that results in a loss of power to the standby bus.
Request To Mandate Quick Reference Handbook (QRH) Change

ALPA requested we ensure that operators adopt the QRH procedural changes that have been implemented by Boeing. ALPA stated that incorporating the QRH procedural changes would help to ensure that an event similar to the event that prompted the NPRM (77 FR 75402, December 20, 2012) does not occur during the 60-month compliance time.

We partially agree with the commenter’s request. We agree that incorporating the QRH change prior to implementing the design change helps mitigate the unsafe condition. We disagree with mandating incorporation of the QRH change. We have evaluated the risk and have determined that accomplishing this final rule within the required compliance time adequately addresses the unsafe condition without the need for any additional interim actions. We have determined this AD action is appropriate based on the probability of occurrence, without requiring that operators incorporate the temporary procedural changes prior to incorporating the required design changes. We have not changed this final rule in this regard. Request To Specify Alternative Relay Locations

United Airlines (UAL) requested that we specify alternate locations for the new air/ground relay in the P36 panel versus the location specified in Figure 15, Sheet 2, of Boeing Special Attention Service Bulletin 757–24–0132, Revision 1, dated June 19, 2012 (which is the service information referenced in the NPRM (77 FR 75402, December 20, 2012)). UAL stated that operators will need to apply for alternative methods of compliance (AMOCs) if they have used the location described in the service information for supplemental type certificate (STC) projects.

We disagree with the commenter’s request to specify alternate relay locations. Figure 15, Sheet 2, of Boeing Special Attention Service Bulletin 757– 24–0132, Revision 1, dated June 19, 2012, already provides a note with regard to the relay installation that states, ‘‘if location is used, the new relay can be installed anywhere on the same row.’’ We have not changed this final rule in this regard. Request To Change Wire Bundle Routing

UAL requested that the wire bundle routing described in Figure 1, Sheet 2, of Boeing Special Attention Service Bulletin 757–24–0132, Revision 1, dated June 19, 2012, be moved to a location that is easier to access. UAL stated that bundle routing near diamond ‘‘B’’ by station 288 can be very difficult because this is behind the P6 panel, which cannot be moved. UAL suggested that following a path in a bundle more forward would be easier. UAL also stated that removing the G1A galley for access is only feasible in a C-check environment; otherwise the cost is prohibitive.

We disagree with the commenter’s request to change the wire bundle routing. Wire bundle W2078 is an existing wire bundle being changed for this modification. The changes to this wire bundle are done near the P5 and P36 panel. Figure 1, of Boeing Special Attention Service Bulletin 757–24– 0132, Revision 1, dated June 19, 2012, is only meant to show that the bundle is routed to both panels and the P6 panel, but it does not require a modification in that area.

Figures 2 through 8 of Boeing Special Attention Service Bulletin 757–24– 0132, Revision 1, dated June 19, 2012, show the wiring change. The wire from the P6 panel (W2078–0 150–22) is an existing wire and is only modified near the P5 panel (flag note 8). Furthermore, the G1A galley is only removed if it is necessary. Note 5 of section 3.A., General Information, of Boeing Special Attention Service Bulletin 757–24– 0132, Revision 1, dated June 19, 2012, states that, ‘‘If it is necessary to remove more parts for access, you can remove those parts. If you can get access without removing identified parts, it is not necessary to remove all of the identified parts. Jacking and shoring limitations must be observed.’’ Therefore, operators can remove other items if it is easier for them.

Finally, in developing an appropriate compliance time for this AD, we considered not only the safety implications, but the manufacturer’s recommendations and the practical aspect of accomplishing the actions within an interval of time that corresponds to typical scheduled maintenance for affected operators. We have determined that a 60-month compliance time will ensure an acceptable level of safety and allow the modifications to be done during scheduled maintenance intervals for most affected operators. Also, the Boeing service information cited in the NPRM (77 FR 75402, December 20, 2012), has been available to operators since June 2012; therefore, operators have had ample time to consider initiating those actions that this final rule requires. We have not changed this final rule in this regard.

Statement of STC Effect on Applicability

Aviation Partners Boeing stated that the installation of winglets per STC ST01920SE ( http://rgl.faa.gov/ Regulatory

_ and

_ Guidance

_ Library/ rgstc.nsf/0/ 082838ee177dbf62862576a4005cdfc0/ $FILE/ST01920SE.pdf ) or STC ST01518SE ( http://rgl.faa.gov/ Regulatory

_ and

_ Guidance

_ Library/ rgstc.nsf/0/ 48e13cdfbbc32cf4862576a4005d308b/ $FILE/ST01518SE.pdf ) do not affect the accomplishment of the manufacturer’s service instructions.

We have added new paragraph (c)(3) to this final rule to state that installation of STC ST01920SE or STC ST01518SE does not affect the ability to accomplish the actions required by this final rule. Therefore, for airplanes on which STC ST01920SE or STC ST01518SE is installed, a ‘‘change in product’’ AMOC approval request is not necessary to comply with the requirements of 14 CFR
39.17.

Conclusion

We reviewed the relevant data, considered the comments received, and determined that air safety and the


### 72566 Federal Register / Vol. 78, No. 232 / Tuesday, December 3, 2013 / Rules and Regulations

public interest require adopting this AD with the change described previously and minor editorial changes. We have determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM (77 FR 75402, December 20, 2012) for correcting the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM (77 FR 75402, December 20, 2012). Costs of Compliance

We estimate that this AD affects 1,085 airplanes of U.S. registry.

We estimate the following costs to comply with this AD:



### E STIMATED 

### C OSTS

Action Labor cost Parts cost Cost per product Cost on U.S. operators

Install new air/ground relay; 674

Model 757 airplanes. 23 work-hours × $85 per hour = $1,955. Up to $733 ................. Up to $2,688 .............. Up to $1,811,712.

Install new air/ground relay; 411

Model 767 airplanes. Up to 35 work-hours × $85 per hour = $2,975. Up to $881 ................. Up to $3,856 .............. Up to $1,584,816.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA’s authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency’s authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701: ‘‘General requirements.’’ Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. Regulatory Findings

This AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a ‘‘significant regulatory action’’ under Executive Order 12866,

(2) Is not a ‘‘significant rule’’ under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979),

(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 adding the following new airworthiness directive (AD):
2013–24–10 The Boeing Company: Amendment 39–17684; Docket No. FAA–2012–1229; Directorate Identifier 2012–NM–135–AD.
(a) Effective Date

This AD is effective January 7, 2014.

(b) Affected ADs

None.
(c) Applicability

This AD applies to The Boeing Company airplanes, certificated in any category, identified in paragraphs (c)(1) and (c)(2) of this AD.

(1) Model 757–200, –200PF, –200CB, and –300 series airplanes, as identified in Boeing Special Attention Service Bulletin 757–24– 0132, Revision 1, dated June 19, 2012.

(2) Model 767–200, –300, –300F, and –400ER series airplanes, as identified in Boeing Special Attention Service Bulletin 767–24–0200, Revision 1, dated September 13, 2012.

(3) Installation of Supplemental Type Certificate (STC) ST01920SE ( http:// rgl.faa.gov/Regulatory

_ and

_ Guidance

_ Library/rgstc.nsf/0/ 082838ee177dbf62862576a4005cdfc0/$FILE/ ST01920SE.pdf ) or STC ST01518SE ( http:// rgl.faa.gov/Regulatory

_ and

_ Guidance

_ Library/rgstc.nsf/0/ 48e13cdfbbc32cf4862576a4005d308b/$FILE/ ST01518SE.pdf ) does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01920SE or STC ST01518SE is installed, a ’’change in product’’ alternative method of compliance (AMOC) approval request is not necessary to comply with the requirements of 14 CFR 39.17.
(d) Subject

Joint Aircraft System Component (JASC)/ Air Transport Association (ATA) of America Code 24, Electrical Power.

(e) Unsafe Condition

This AD was prompted by a standby power relay failure and subsequent illumination of the ‘‘STANDBY BUS OFF’’ light, which led the flightcrew to set the standby power switch to the ‘‘BAT’’ position, isolating the battery and standby buses, disabling the battery charger, and eventually causing the main battery to be depleted. We are issuing this AD to prevent discharge of the main battery, which could result in multiple system degradation, reduced airplane controllability, and runway excursion upon landing.
(f) Compliance

Comply with this AD within the compliance times specified, unless already done.
(g) Installation

Within 60 months after the effective date of this AD: Do wiring changes and install a new air/ground relay to the battery charger system, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 757–24– 0132, Revision 1, dated June 19, 2012; or Boeing Special Attention Service Bulletin 767–24–0200, Revision 1, dated September 13, 2012; as applicable.

(h) Credit for Previous Actions

(1) For Model 757 airplanes: This paragraph provides credit for the actions required by paragraph (g) of this AD if those actions were performed before the effective date of this AD using Boeing Special Attention Service Bulletin 757–24–0132, dated April 14, 2011, which is not incorporated by reference in this AD.


### 72567 Federal Register / Vol. 78, No. 232 / Tuesday, December 3, 2013 / Rules and Regulations

(2) For Model 767 airplanes: This paragraph provides credit for the actions required by paragraph (g) of this AD if those actions were performed before the effective date of this AD using Boeing Special Attention Service Bulletin 767–24–0200, dated April 14, 2011, which is not incorporated by reference, provided that a functional test of the battery charger system is done, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 767–24– 0200, Revision 1, dated September 13, 2012, within 60 months after the effective date of this AD.
(i) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Seattle 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 (j)(1) of this AD. Information may be emailed to: 9-ANM-Seattle-ACO-AMOCRequests@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.
(j) Related Information

(1) For more information about this AD, contact Marie Hogestad, Aerospace Engineer, Systems and Equipment Branch, ANM–130S, Seattle Aircraft Certification Office (ACO), FAA, 1601 Lind Avenue SW., Renton, WA 98057–3356; phone: 425–917–6418; fax: 425– 917–6590; email: marie.hogestad@faa.gov

.

(2) Service information identified in this AD that is not incorporated by reference may be obtained at the addresses specified in paragraphs (k)(3) and (k)(4) of this AD.
(k) 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.

(i) Boeing Special Attention Service Bulletin 757–24–0132, Revision 1, dated June 19, 2012.

(ii) Boeing Special Attention Service Bulletin 767–24–0200, Revision 1, dated September 13, 2012.

(3) 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 206–544–5000, extension 1; fax 206–766– 5680; Internet https:// www.myboeingfleet.com.

(4) You may view this service information at 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.

(5) 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/ibrlocations.html.

Issued in Renton, Washington, on November 15, 2013. Jeffrey E. Duven, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 2013–28441 Filed 12–2–13; 8:45 am]

**BILLING CODE 4910–13–P**

**DEPARTMENT OF TRANSPORTATION**

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2013–0499; Directorate Identifier 2013–NE–20–AD; Amendment 39–**  **17673; AD 2013–23–18]**

**RIN 2120–AA64**

**Airworthiness Directives; General Electric Company Turbofan Engines** 

**AGENCY :**  Federal Aviation Administration (FAA), DOT.

**ACTION :**  Final rule.

**SUMMARY :**  We are adopting a new airworthiness directive (AD) for certain General Electric Company (GE) GE90– 110B1 and –115B turbofan engines. This AD was prompted by multiple events of a leaking variable bypass valve (VBV) actuator fuel supply tube. This AD requires replacement of this VBV actuator fuel supply tube with a part eligible for installation. We are issuing this AD to prevent failure of the affected fuel supply tube, fuel leakage, engine fire, and damage to the airplane.

**DATES :**  This AD is effective January 7,
2014. 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 AD, the regulatory evaluation, any comments received, and other information. The address for the Docket Office (phone: 800–647–5527) is Document Management Facility, U.S. Department of Transportation, Docket Operations, M–30, West Building Ground Floor, Room W12–140, 1200 New Jersey Avenue SE., Washington, DC 20590.

**FOR FURTHER INFORMATION CONTACT :**  Jason Yang, Aerospace Engineer, Engine Certification Office, FAA, Engine & Propeller Directorate, 12 New England Executive Park, Burlington, MA 01803; phone: 781–238–7747; fax: 781–238– 7199; email: jason.yang@faa.gov.

**SUPPLEMENTARY INFORMATION :** 

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to the specified products. The NPRM published in the Federal Register on July, 25, 2013 (78 FR 44899, July 25, 2013). The NPRM proposed to require replacement of the affected VBV actuator fuel supply tube, part number 2165M22P01, with a part eligible for installation.

Comments

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the proposal and the FAA’s response to each comment. Agreement With the Proposed AD

The Boeing Company and FedEx Express agreed with the AD as proposed. Request To Change the Compliance Time

GE requested that we change the compliance time in this AD from ‘‘at the next shop visit, after the effective date of this AD’’ to ‘‘as soon as possible without effect on revenue service, but before April 1, 2014.’’ No justification was provided for the change.

We do not agree. Replacement of the VBV actuator fuel supply tube at the next shop visit maintains an acceptable level of safety for the fleet, based on safety risk analysis. We have no data to support that a more aggressive replacement schedule is required to maintain that acceptable level of safety. We did not change the AD.

Conclusion

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD as proposed.