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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2010-1107; Directorate Identifier 2009-NM-263-AD]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Notice of proposed rulemaking (NPRM).

# SUMMARY:

We propose to adopt a new airworthiness directive (AD) for certain Model 750 airplanes. This proposed AD would require an inspection to determine the serial numbers of the auxiliary power unit (APU) generator and the left and right engine direct current (DC) generators, and related corrective actions if necessary. This proposed AD would also require revising the airplane flight manual. This proposed AD results from a report of a DC generator overvoltage event which caused smoke in the cockpit and damage to numerous avionics and electrical components. We are proposing this AD to detect and correct an overvoltage condition on the DC electrical busses caused by exciter stator winding failures, and subsequent failure of the generator control unit (GCU) overvoltage protection circuitry, which could result in damage to critical electrical and avionics components.

# DATES:

We must receive comments on this proposed AD by December 27, 2010.

# ADDRESSES:

You may send comments by any of the following methods:
      -  Federal eRulemaking Portal:                          Go to                          http://www.regulations.gov.                          Follow the instructions for submitting comments.                    
      -  Fax:                          202-493-2251.                    
      -  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:                          U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.                    

                        For service information identified in this proposed AD, contact Cessna Aircraft Co., P.O. Box 7706, Wichita, Kansas 67277; telephone 316-517-6215; fax 316-517-5802; e-mail                         *citationpubs@cessna.textron.com;*                         Internet                         *https://www.cessnasupport.com/​newlogin.html.*                         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                           ( print page 68732)                        street address for the Docket Office (telephone 800-647-5527) is in the                     **ADDRESSES**                     section. Comments will be available in the AD docket shortly after receipt.                

# FOR FURTHER INFORMATION CONTACT:

Raymond Johnston, Aerospace Engineer, Electrical Systems and Avionics, ACE-119W, FAA, Wichita Aircraft Certification Office (ACO), 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4197; fax (316) 946-4107.

# 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-2010-1107; Directorate Identifier 2009-NM-263-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

We have received a report of a DC generator overvoltage event which caused smoke in the cockpit and damage to numerous avionics and electrical components. This event occurred on the ground before an engine was started. This event was determined to be the result of a short in the APU generator windings and subsequent damage to the overvoltage protection circuit in the GCU due to prolonged holding of the generator reset switch in the cockpit. This condition, if not corrected, could result in an overvoltage condition on the DC electrical busses caused by exciter stator winding failures, and subsequent failure of the GCU overvoltage protection circuitry associated with the engine and APU DC generators.

## Relevant Service Information

We have reviewed Cessna Service Letter SL750-24-08, dated August 13, 2009, which describes procedures for an inspection to determine the serial number of the APU generator and the left and right engine 400 amp DC generators. For any airplane having any generator with a serial number from 060 through 297 without suffix “C,” the service letter specifies to replace the affected generator(s) before further flight. We also reviewed Cessna Airplane Flight Manual Temporary Changes 75EUMA TC-R01-35, dated May 8, 2009; 75EUA TC-R01-35, dated May 8, 2009; and 75FMA TC-R01-46, dated April 23, 2009; which provide instructions not to hold the main or APU generator reset switches in the reset position for more than one second and to make no more than two attempts to reset a generator.

## FAA's Determination and Requirements of This Proposed AD

We are proposing this AD because we evaluated all relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. This proposed AD would require accomplishing the actions specified in the service information described previously.

## Interim Action

We consider this proposed AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, we might consider additional rulemaking.

## Costs of Compliance

We estimate that this proposed AD would affect 67 airplanes of U.S. registry. We also estimate that it would take up to 10 work-hours per product to comply with this proposed AD. The average labor rate is $85 per work-hour. Based on these figures, we estimate the cost of this proposed AD to the U.S. operators to be up to $56,950, or $850 per product.

## 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 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 this 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), and

3. 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.

You can find our regulatory evaluation and the estimated costs of compliance in the AD Docket.

# 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 

2. The FAA amends § 39.13 by adding the following new AD:

**The Cessna Aircraft Company:**                                 Docket No. FAA-2010-1107; Directorate Identifier 2009-NM-263-AD.                            

## Comments Due Date

(a) We must receive comments by December 27, 2010.

## Affected ADs

(b) None.

## Applicability

                                (c) This AD applies to The Cessna Aircraft Company Model 750 airplanes, certificated in any category, having serial numbers -0222, and -0225 and subsequent.                                      ( print page 68733)    

## Subject

(d) Air Transport Association (ATA) of America Code 24: Electrical power.

## Unsafe Condition

(e) This AD results from a report of a direct current (DC) generator overvoltage event which caused smoke in the cockpit and damage to numerous avionics and electrical components. The Federal Aviation Administration is issuing this AD to detect and correct an overvoltage condition on the DC electrical busses caused by exciter stator winding failures, and subsequent failure of the generator control unit overvoltage protection circuitry, which could result in damage to critical electrical and avionics components.

## Compliance

(f) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

## Inspection

(g) For airplanes having serial numbers -0222, -0225 through -0293 inclusive, -0295, -0296, and -0298: Within 6 months or 600 flight hours after the effective date of this AD, whichever occurs later, inspect to determine the serial number of the auxiliary power unit (APU) generator and the left and right engine 400 amp DC generators, in accordance with the Accomplishment Instructions of Cessna Service Letter SL750-24-08, dated August 13, 2009. For airplanes that have one or more generators having a serial number 060 through 297 inclusive without suffix “C,” before further flight, replace the affected generator(s) with a new or serviceable generator, in accordance with the Accomplishment Instructions of Cessna Service Letter SL750-24-08, dated August 13, 2009.

## Revision of the Airplane Flight Manual (AFM)

(h) For airplanes having serial numbers -0222, and -0225 and subsequent: Within 30 days after the effective date of this AD, revise Section II, Operating Limitations, Generator Limitations, page 2-12, of the applicable airplane flight manual (AFM) to include the information in the applicable Temporary Change (TC) required by paragraph (h)(1), (h)(2), or (h)(3) of this AD. These TCs introduce procedures for resetting the APU generator. Operate the airplane according to the limitations and procedures in the TCs.

(1) For Model 750 Citation X (750-0173 and on and airplanes incorporating SB750-71-10 AFM 75FMA, Revision 1, dated June 13, 2002): Insert Cessna Temporary Change (TC) 75FMA TC-R01-46, dated April 23, 2009.

(2) For Model 750 Citation X (750-0173 and on and airplanes incorporating SB750-71-10) AFM 75EUA, Revision 1, dated June 19, 2002: Insert Cessna TC 75EUA TC-R01-35, dated May 8, 2009.

(3) For Model 750 Citation X (750-0173 and on and airplanes incorporating SB750-71-10) AFM 75EUMA, Revision 1, dated June 30, 2002: Insert Cessna TC 75EUMA TC-R01-35, dated May 8, 2009.

# Note 1: 

The AFM revisions required by paragraph (g) of this AD may be done by inserting copies of TCs 75FMA TC-R01-46, dated April 23, 2009; 75EUA TC-R01-35, dated May 8, 2009; or 75EUMA TC-R01-35, dated May 8, 2009; into the applicable AFM. When these TCs have been included in general revisions of the AFM, the general revisions may be inserted into the AFM, provided the relevant information in the general revision is identical to that in TCs.

## Parts Installation

(i) As of the effective date of this AD, no person may install any Pacific Scientific generators having part number 92841-1 (9914752-1) that has serial numbers 060 through 297 without the suffix “C” on any airplane.

## Alternative Methods of Compliance (AMOCs)

                                (j)(1) The Manager, Wichita Aircraft Certification Office, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to                                 *ATTN:*                                 Raymond Johnston, Aerospace Engineer, Electrical Systems and Avionics, ACE-119W, FAA, Wichita Aircraft Certification Office (ACO), 1801 Airport Road, Room 100, Mid-Continent Airport, Wichita, Kansas 67209; telephone (316) 946-4197; fax (316) 946-4107.                            

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD.

Issued in Renton, Washington, on November 2, 2010.

Dionne Palermo,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

[FR Doc. 2010-28274 Filed 11-8-10; 8:45 am]

BILLING CODE 4910-13-P