## 24344 Federal Register / Vol. 77, No. 79 / Tuesday, April 24, 2012 / Rules and Regulations

(h) No Alternative Inspections for Paragraph (g) of This AD

Except as required by paragraph (i) of this AD, after accomplishing the actions specified in paragraph (g) of this AD, no alternative inspections or inspection intervals may be used unless the inspection or inspection interval is approved by the Manager, International Branch, ANM–116, Transport Airplane Directorate, FAA, or the Age ˆ ncia Nacional de Aviac

 ̧ a  ̃ o Civil (ANAC) (or its delegated agent); or unless the inspection or interval is approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (k)(1) of this AD.
(i) New Requirements of This AD: Revising the Maintenance Program

(1) Within 60 days after the effective date of this AD: Revise the maintenance program to incorporate the new or revised tasks specified in Part 2—Airworthiness Limitation Inspection (ALI)—Structures, of Appendix A, Airworthiness Limitations, of the EMBRAER 170 MRBR MRB–1621, Revision 7, dated November 11, 2010; and EMBRAER Temporary Revision (TR) 7–1, dated February 11, 2011, to Part 2—Airworthiness Limitation Inspection (ALI)—Structures, of Appendix A, Airworthiness Limitations, of the EMBRAER 170 MRBR MRB–1621, Revision 7; with the initial compliance times and intervals specified in these documents.

(2) The initial compliance times for the tasks start from the date of issuance of the original Brazilian airworthiness certificate or the date of issuance of the original Brazilian export certificate of airworthiness of the applicable airplane at the applicable time specified in the tasks, or within 600 flight cycles after revising the maintenance program, whichever occurs later. For certain tasks, the compliance times depend on the pre-modification and post-modification status of the actions specified in the associated service bulletin, as specified in the ‘‘Applicability’’ column of Part 2— Airworthiness Limitation Inspection (ALI)— Structures, of Appendix A, Airworthiness Limitations, of the EMBRAER 170 MRBR MRB–1621, Revision 7, dated November 11, 2010; and EMBRAER Temporary Revision 7– 1, dated February 11, 2011, to Part 2— Airworthiness Limitation Inspection (ALI)— Structures, of Appendix A, Airworthiness Limitations of the EMBRAER 170 MRBR MRB–1621, Revision 7.

(3) For tasks identified in the documents identified in paragraph (i)(1) of this AD, doing the initial task required by this paragraph terminates the requirements of paragraph (g) of this AD for that task.
(j) No Alternative Actions Intervals, and/or Critical Design Configuration Control Limitations (CDCCLs)

After accomplishing the revisions required by paragraph (i) of this AD, no alternative actions (e.g., inspections), intervals, and/or CDCCLs may be used other than those specified in Part 2—Airworthiness Limitation Inspection (ALI)—Structures, of Appendix A, Airworthiness Limitations, of the EMBRAER 170 MRBR MRB–1621, Revision 7, dated November 11, 2010; and EMBRAER Temporary Revision 7–1, dated February 11, 2011, to Part 2—Airworthiness Limitation Inspection (ALI)—Structures, of Appendix A, Airworthiness Limitations, of the EMBRAER 170 MRBR MRB–1621, Revision 7, unless the actions, intervals, and/or CDCCLs are approved as an AMOC in accordance with the procedures specified in paragraph (k)(1) of this AD.
(k) Other FAA AD Provisions

The following provisions also apply to this AD:

(1) Alternative Methods of Compliance (AMOCs): The Manager, International Branch, ANM–116, 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 International Branch, send it to ATTN: Cindy Ashforth, Aerospace Engineer, International Branch, ANM–116, Transport Airplane Directorate, FAA, 1601 Lind Avenue SW., Renton, Washington 98057– 3356; telephone 425–227–2768; fax 425–227– 1320. Information may be emailed to: 9-ANM-116-AMOC-REQUESTS@faa.gov. 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. The AMOC approval letter must specifically reference this AD.

(2) Airworthy Product: For any requirement in this AD to obtain corrective actions from a manufacturer or other source, use these actions if they are FAA-approved. Corrective actions are considered FAA-approved if they are approved by the State of Design Authority (or their delegated agent). You are required to assure the product is airworthy before it is returned to service.
(l) Related Information

Refer to MCAI Brazilian Airworthiness Directive 2011–04–01, dated May 5, 2011; and Part 2—Airworthiness Limitation Inspection (ALI)—Structures, of Appendix A, Airworthiness Limitations, of the EMBRAER 170 MRBR MRB–1621, Revision 7, dated November 11, 2010; and EMBRAER Temporary Revision 7–1, dated February 11, 2011, to Part 2—Airworthiness Limitation Inspection (ALI)—Structures, of Appendix A, Airworthiness Limitations, of the EMBRAER 170 MRBR MRB–1621, Revision 7; for related information.
(m) Material Incorporated by Reference

(1) You must use the following service information to do the actions required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference (IBR) of the following service information under 5 U.S.C. 552(a) and 1 CFR part 51 on the date specified.

(2) The following service information was approved for IBR on May 29, 2012.

(i) Part 2—Airworthiness Limitation Inspection (ALI)—Structures, of Appendix A, Airworthiness Limitations, of the EMBRAER 170 MRBR MRB–1621, Revision 7, dated November 11, 2010. *Only the title page of this document specifies the revision level of the document.

(ii) EMBRAER Temporary Revision 7–1, dated February 11, 2011, to Part 2— Airworthiness Limitation Inspection (ALI)— Structures, of Appendix A, Airworthiness Limitations of the EMBRAER 170 MRBR MRB–1621, Revision 7.

(3) The following service information was approved for IBR on July 6, 2010 (75 FR 30284, June 1, 2010):

(i) EMBRAER Temporary Revision 4–1, dated October 15, 2007, to Appendix A–Part 2 of the EMBRAER 170 Maintenance Review Board Report MRB–1621.

(ii) EMBRAER Temporary Revision 4–3, dated December 6, 2007, to Appendix A— Part 2 of the EMBRAER 170 Maintenance Review Board Report MRB–1621.

(iii) EMBRAER Temporary Revision 4–4, dated January 18, 2008, to Appendix A– Part 2 of the EMBRAER 170 Maintenance Review Board Report MRB–1621.

(4) For service information identified in this AD, contact Empresa Brasileira de Aeronautica S.A. (EMBRAER), Technical Publications Section (PC 060), Av. Brigadeiro Faria Lima, 2170–Putim–12227–901 Sa  ̃ o Jose dos Campos—SP—BRASIL; telephone +55 12 3927–5852 or +55 12 3309–0732; fax +55 12 3927–7546; email: distrib@embraer.com.br; Internet: http://www.flyembraer.com.

(5) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington. For information on the availability of this material at the FAA, call
425–227–1221.

(6) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at an NARA facility, call 202–741– 6030, or go to http://www.archives.gov/ federal

_register/code

_ of

_ federal

_regulations/ ibr

_locations.html. Issued in Renton, Washington, on March 29, 2012. Kalene C. Yanamura, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 2012–9500 Filed 4–23–12; 8:45 am]

**BILLING CODE 4910–13–P**



### DEPARTMENT OF TRANSPORTATION

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2011–1069; Directorate Identifier 2011–NM–025–AD; Amendment**  **39–17025; AD 2012–08–08]**

**RIN 2120–AA64**



### Airworthiness Directives; Learjet Inc.

**AGENCY** 

### : Federal Aviation Administration (FAA), DOT.

**ACTION** 

### : Final rule.


## 24345 Federal Register / Vol. 77, No. 79 / Tuesday, April 24, 2012 / Rules and Regulations

**SUMMARY** 

### : We are adopting a new airworthiness directive (AD) for all Learjet Inc., Model 45 airplanes. This AD was prompted by changes to the Airworthiness Limitations Section (ALS) of the maintenance manual,which adds life-limits, revises lifelimits, or adds inspections not previously identified. This AD requires revising the maintenance program toinclude new or more restrictive lifelimits and inspections. We are issuing this AD to limit exposure of flight critical components to corrosion, cracking, or failure due to life-limits, which if not corrected, could result in loss of roll control, fatigue cracking, or loss of structural components.

**DATES** 

### : This AD is effective May 29,
2012.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in the AD as of May 29, 2012.

**ADDRESSES** 

### : For service information identified in this AD, contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209–2942; telephone 316–946–2000; fax 316–946–2220; email ac.ict@aero. bombardier.com; Internet http://www. bombardier.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 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** 

### : William Griffith, Aerospace Engineer, Airframe Branch, ACE–118W, FAA, Wichita Aircraft Certification Office,1801 Airport Road, Room 100, MidContinent Airport, Wichita, Kansas 67209; phone: 316–946–4116; fax: 316– 946–4107; email: William.E.Griffith@ faa.gov.

**SUPPLEMENTARY INFORMATION** 

### :

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM was published in the Federal Register on October 19, 2011 (76 FR 64851). That NPRM proposed to require revising the maintenance program toinclude new or more restrictive lifelimits and inspections.

Comments

We gave the public the opportunity to participate in developing this AD. The following presents the comment received on the proposal and the FAA’s response to the comment. Request To Revisit Interpretation of the Meaning of the Word ‘‘Current’’

Flight Concepts requested we revisit our interpretation of the word ‘‘current’’ so that the improper use of the airworthiness directive system would not be needed. This commenter justified its request by providing Webster’s definition of the word ‘‘current.’’

We infer that the requested change is in reference to an FAA memorandum regarding the legal interpretation of section 91.409(f)(3) of the Federal Aviation Regulations (14 CFR 91.409) and is not specifically applicable to this AD.

We do not agree that the word ‘‘current’’ needs to be defined for this AD. The utilization of the word ‘‘current’’ is not within the textual body of this AD. This AD requires revising the maintenance program by incorporating certain tasks, which when performed, address unsafe conditions. Operators utilizing earlier versions of manual-specific maintenance programs may not be bound or obligated to follow newer releases or updates to these maintenance programs. The issue of the terminology of the word ‘‘current’’ and explanation of the requirement for FAA mandates to newer maintenance actions via the AD process is addressed in an FAA memorandum dated August 13, 2010, from the Office of the Chief Counsel. This AD ensures that those specific tasks covering the unsafe conditions are followed by all operators of this airplane model. We have not changed the AD in this regard. Explanation of Additional Changes Made to This AD

We have redesignated Note 1 of the NPRM (76 FR 64851, October 19, 2011) as paragraph (c)(2) of this AD, paragraph (c) as paragraph (c)(1) of this AD, and Note 2 of the NPRM as Note 1 to paragraph (g) of this AD.

IRN # N3220105 was incorrectly included in table 1 of the NPRM (76 FR 64851, October 19, 2011). We have removed it from the final rule.

Conclusion

We reviewed the relevant data, considered the comment received, and determined that air safety and the public interest require adopting the AD as proposed, except for minor editorial changes. We have determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM (76 FR 64851, October 19, 2011) for correcting the unsafe condition; and

• Do not add any additional burden upon the public than was already proposed in the NPRM (76 FR 64851, October 19, 2011). Costs of Compliance

We estimate that this AD affects 336 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

Change ALS in maintenance manual ............. 1 work-hour × $85 per hour = $85 ................. $0 $85 $28,560



### 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


## 24346 Federal Register / Vol. 77, No. 79 / Tuesday, April 24, 2012 / Rules and Regulations

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):
2012–08–08 Learjet Inc.: Amendment 39– 17025; Docket No. FAA–2011–1069; Directorate Identifier 2011–NM–025–AD.

(a) Effective Date

This AD is effective May 29, 2012.

(b) Affected ADs

None (c) Applicability

(1) This AD applies to all Learjet Inc., Model 45 airplanes, certificated in any category.

(2) This AD requires revisions to certain operator maintenance documents to include new actions (e.g. inspections). Compliance with these actions is required by 14 CFR 91.403(c). For airplanes that have been previously modified, altered, or repaired in the areas addressed by these actions, the operator may not be able to accomplish the inspections described in the revisions. In this situation, to comply with 14 CFR 91.403(c), the operator must request approval for an alternative method of compliance according to paragraph (i) of this AD. The request should include a description of changes to the required actions that will ensure the continued operational safety of the airplane. The FAA has provided guidance for this determination in FAA Advisory Circular (AC) 25.1529–1A, dated November 20, 2007. http://rgl.faa.gov/Regulatory

_ and

_ Guidance

_ Library/rgAdvisoryCircular.nsf/list/ AC%2025.1529-1A/$FILE/AC%2025.1529- 1A.pdf.
(d) Subject

Joint Aircraft System Component (JASC)/ Air Transport Association (ATA) of America Code 05, Periodic Inspections.

(e) Unsafe Condition

This AD was prompted by changes to the Airworthiness Limitations Section (ALS) of the maintenance manual (MM), which adds life-limits, revises life-limits, or adds inspections not previously identified. We are issuing this AD to limit exposure of flight critical components to corrosion, cracking, or failure due to life-limits, which if not corrected, could result in loss of roll control, fatigue cracking, or loss of structural components. (f) Compliance

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

Within 90 days after the effective date of this AD, revise the maintenance program by incorporating the applicable inspection reference number (IRN) tasks identified in table 1 of this AD, as specified in Chapter 04, Airworthiness Limitations, of the Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10, 2011; or Bombardier Learjet 40 Maintenance Manual MM–105, Revision 21, dated January 10, 2011; as applicable. The initial task compliance time is within 90 days after the effective date of this AD, or the applicable initial compliance time specified in table 1 of this AD, whichever is later.

Note 1 to paragraph (g) of this AD: IRN #R2710041 shown in table 1 of this AD is identified as IRN # N2710041 in prior revisions of Bombardier Learjet 45 Maintenance Manual MM–104, and Bombardier Learjet 40 Maintenance Manual MM–105.



### T ABLE 

### 1—IRN T ASK 

### R EVISION

Model— IRN #— Initial compliance time— Chapter 04 of these documents—

Model 40, 45 ............... R2710041 ................... Within 10 years after the date of issuance ofthe original standard airworthiness certificate or the date of issuance of the original export certificate of airworthiness, or within10 years after the most recent replacement, whichever occurs later. Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10,2011; or Bombardier Learjet 40 Maintenance Manual MM–105, Revision 21, dated January 10, 2011; as applicable.

Model 40, 45 ............... Q5510091 ................... Within 600 flight hours after the most recent inspection done in accordance with IRN # Q5510091. Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10,2011; or Bombardier Learjet 40 Maintenance Manual MM–105, Revision 21, dated January 10, 2011; as applicable. Model 40, 45 ............... Q5530011 ................... Before the accumulation of 9,600 total flight hours. Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10,2011; or Bombardier Learjet 40 Maintenance Manual MM–105, Revision 21, dated January 10, 2011; as applicable.Model 40, 45 ............... P3220007 ................... Within 48 months after the most recent inspection done in accordance with IRN # P3220007. Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10,2011; or Bombardier Learjet 40 Maintenance Manual MM–105, Revision 21, dated January 10, 2011; as applicable.


## 24347 Federal Register / Vol. 77, No. 79 / Tuesday, April 24, 2012 / Rules and Regulations

T ABLE 

### 1—IRN T ASK 

### R EVISION 

### —Continued

Model— IRN #— Initial compliance time— Chapter 04 of these documents—

Model 40, 45 ............... P3220146 ................... Before the accumulation of 4,800 total landings. Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10,2011; or Bombardier Learjet 40 Maintenance Manual MM–105, Revision 21, dated January 10, 2011; as applicable. Model 40, 45 ............... N3220012, N3220023, N3220035, N3220036, and N3220037. Before the accumulation of 10,000 total landings on the component. Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10,2011; or Bombardier Learjet 40 Maintenance Manual MM–105, Revision 21, dated January 10, 2011; as applicable. Model 40, 45 ............... N3220103, N3220104, and N3220106. Before the accumulation of 17,000 total landings on the component. Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10,2011; or Bombardier Learjet 40 Maintenance Manual MM–105, Revision 21, dated January 10, 2011; as applicable. Model 45 ...................... N5710147, N5710171, and N5710173. Before the accumulation of 6,500 total flight hours. Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10, 2011. Model 45 ...................... N5710175 ................... Before the accumulation of 6,900 total flight hours. Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10, 2011. Model 45 ...................... N5710177 ................... Before the accumulation of 7,000 total flight hours. Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10, 2011.

(h) No Alternative Intervals

After accomplishing the revisions required by paragraph (g) of this AD, no alternative IRN task or IRN task interval may be used unless the IRN task or IRN task interval is approved as an AMOC in accordance with the procedures specified in paragraph (i)(1) of this AD.
(i) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Wichita 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 the Related Information section 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.
(j) Related Information

For more information about this AD, William Griffith, Aerospace Engineer, Airframe Branch, ACE–118W, FAA, Wichita Aircraft Certification Office, 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; phone: 316–946– 4116; fax: 316–946–4107; email: William.E. Griffith@faa.gov.
(k) Material Incorporated by Reference

(1) You must use the following service information to do the actions required by this AD, unless the AD specifies otherwise. The Director of the Federal Register approved the incorporation by reference (IBR) of the following service information under 5 U.S.C. 552(a) and 1 CFR part 51:

(i) Chapter 04, Airworthiness Limitations, of the Bombardier Learjet 45 Maintenance Manual MM–104, Revision 53, dated January 10, 2011. Only the title page and record of revisions pages of this document specify the revision level of the document.

(ii) Chapter 04, Airworthiness Limitations, of the Bombardier Learjet 40 Maintenance Manual MM–105, Revision 21, dated January 10, 2011. Only the title page and record of revisions pages of this document specify the revision level of the document.

(2) For service information identified in this AD, contact Learjet, Inc., One Learjet Way, Wichita, Kansas 67209–2942; telephone 316–946–2000; fax 316–946–2220; email ac. ict@aero.bombardier.com; Internet http:// www.bombardier.com.

(3) 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.

(4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at an NARA facility, call 202–741– 6030, or go to http://www.archives.gov/ federal

_ register/code

_ of

_ federal

_regulations/ ibr

_ locations.html. Issued in Renton, Washington, on April 9,

2012. John Piccola, Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.
[FR Doc. 2012–9393 Filed 4–23–12; 8:45 am]

**BILLING CODE 4910–13–P** 

### DEPARTMENT OF TRANSPORTATION

**Federal Aviation Administration**

**14 CFR Part 39**

**[Docket No. FAA–2011–1223; Directorate Identifier 2011–NM–173–AD; Amendment**  **39–17027; AD 2012–08–10]**

**RIN 2120–AA64**



### Airworthiness Directives; Bombardier, **Inc. Airplanes**

**AGENCY** 

### : Federal Aviation Administration (FAA), Department of Transportation (DOT).

**ACTION** 

### : Final rule.

**SUMMARY** 

### : We are adopting a new airworthiness directive (AD) for certain Bombardier, Inc. Model CL–600–2B16 (CL–604 Variant) airplanes. This AD was prompted by reports of the air driven generator (ADG) failing to power essential buses during functional tests, due to the low threshold setting of the circuit protection on the ADG’s generator control unit (GCU) preventing the ADG from supplying power to the essential buses. This AD requires installing a new or serviceable ADG GCU. We are issuing this AD to prevent loss of power from the ADG to the essential buses which, in the event of an emergency, could prevent continued safe flight.

**DATES** 

### : This AD becomes effective May 29, 2012.

The Director of the Federal Register approved the incorporation by reference