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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2009-0938; Directorate Identifier 2009-CE-052-AD]
          - RIN 2120-AA64

# AGENCY:

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

# ACTION:

Notice of proposed rulemaking (NPRM).

# SUMMARY:

We propose to adopt a new airworthiness directive (AD) for the products listed above. This proposed AD results from mandatory continuing airworthiness information (MCAI) originated by an aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

This Airworthiness Directive (AD) is prompted due to the discovery of cracks caused by stress corrosion in the main-gear support struts. All the main-gear support struts that had cracks were made from material AA2024-T351 which has a lower resistance to stress corrosion cracking.

Such cracks, if undetected, could lead to the failure of the strut during landing which could then cause the Main Landing Gear (MLG) to collapse.

The proposed AD would require actions that are intended to address the unsafe condition described in the MCAI.

# DATES:

We must receive comments on this proposed AD by November 23, 2009.

# 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.                    

## Examining the AD Docket

                    You may examine the AD docket on the Internet at                     *http://www.regulations.gov;*                     or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this proposed AD, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (telephone (800) 647-5527) is in the                     **ADDRESSES**                     section. Comments will be available in the AD docket shortly after receipt.                

# FOR FURTHER INFORMATION CONTACT:

                        Doug Rudolph, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106;                         *telephone:*                         (816) 329-4059;                         *fax:*                         (816) 329-4090;                         *e-mail: doug.rudolph@faa.gov.*

# 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-2009-0938; Directorate Identifier 2009-CE-052-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

The Federal Office of Civil Aviation (FOCA), which is the aviation authority for Switzerland, has issued FOCA AD HB-2009-011, dated September 10, 2009 (referred to after this as “the MCAI”), to correct an unsafe condition for the specified products. The MCAI states:

This Airworthiness Directive (AD) is prompted due to the discovery of cracks caused by stress corrosion in the main-gear support struts. All the main-gear support struts that had cracks were made from material AA2024-T351 which has a lower resistance to stress corrosion cracking.

Such cracks, if undetected, could lead to the failure of the strut during landing which could then cause the Main Landing Gear (MLG) to collapse.

In order to correct and control the situation, this AD mandates the identification of the main-gear support struts to check if they have rounded clevis lugs and a Non-Destructive Inspection (NDI) procedure on the main-gear support struts if they have chamfered clevis lugs.

For main-gear support struts with chamfered clevis lugs that show cracks during the NDI, the MCAI also requires replacing any cracked main-gear support struts with parts of improved design. You may obtain further information by examining the MCAI in the AD docket.

## Relevant Service Information

PILATUS Aircraft Ltd. has issued PILATUS PC-7 Service Bulletin No. 32-024, Rev. No. 1, dated November 17, 2008; and PILATUS PC-7 Service Bulletin No. 32-025, Rev. No. 1, dated November 17, 2008. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.

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

                    This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to our bilateral agreement with this State of                           ( print page 52157)                        Design Authority, they have notified us of the unsafe condition described in the MCAI and service information referenced above. We are proposing this AD because we evaluated all information and determined the unsafe condition exists and is likely to exist or develop on other products of the same type design.                

## Differences Between This Proposed AD and the MCAI or Service Information

We have reviewed the MCAI and related service information and, in general, agree with their substance. But we might have found it necessary to use different words from those in the MCAI to ensure the AD is clear for U.S. operators and is enforceable. In making these changes, we do not intend to differ substantively from the information provided in the MCAI and related service information.

We might also have proposed different actions in this AD from those in the MCAI in order to follow FAA policies. Any such differences are highlighted in a NOTE within the proposed AD.

## Costs of Compliance

We estimate that this proposed AD will affect 10 products of U.S. registry. We also estimate that it would take about 4 work-hours per product to comply with the basic requirements of this proposed AD. The average labor rate is $80 per work-hour.

Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $3,200, or $320 per product.

In addition, we estimate that any necessary follow-on actions would take about 20 work-hours and require parts costing $20,000, for a cost of $21,600 per product. We have no way of determining the number of products that may need these actions.

## 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it 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:

**PILATUS Aircraft Ltd:**                                 Docket No. FAA-2009-0938; Directorate Identifier  2009-CE-052-AD.                            

## Comments Due Date

(a) We must receive comments by November 23, 2009.

## Affected ADs

(b) None.

## Applicability

(c) This AD applies to Model PC-7 airplanes, manufacturer serial numbers 101 through 618 that are:

(1) Equipped with main-gear support struts part number (P/N) 532.10.09.039 or P/N 114.48.07.172; and

(2) Certificated in any category.

## Subject

(d) Air Transport Association of America (ATA) Code 32: Landing Gear.

## Reason

(e) The mandatory continuing airworthiness information (MCAI) states:

This Airworthiness Directive (AD) is prompted due to the discovery of cracks caused by stress corrosion in the main-gear support struts. All the main-gear support struts that had cracks were made from material AA2024-T351 which has a lower resistance to stress corrosion cracking.

Such cracks, if undetected, could lead to the failure of the strut during landing which could then cause the Main Landing Gear (MLG) to collapse.

In order to correct and control the situation, this AD mandates the identification of the main-gear support struts to check if they have rounded clevis lugs and a Non-Destructive Inspection (NDI) procedure on the main-gear support struts if they have chamfered clevis lugs.

For main-gear support struts with chamfered clevis lugs that show cracks during the NDI, the MCAI also requires replacing any cracked main-gear support struts with parts of improved design. You may obtain further information by examining the MCAI in the AD docket.

## Actions and Compliance

(f) Unless already done, do the following actions:

(1) Within the next 30 hours time-in-service (TIS) after the effective date of this AD or within the next 30 days after the effective date of this AD, whichever occurs first, visually inspect the left and right main-gear support struts to determine if they have rounded or chamfered clevis lugs. Do the inspection following paragraph 3.A. of PILATUS PC-7 Service Bulletin No. 32-024, Rev. No. 1, dated November 17, 2008.

(2) Based on the results of the inspection required in paragraph (f)(1) of this AD, if the main-gear support strut has rounded clevis lugs, no further action is required except the requirement specified in paragraph (f)(4) of this AD still applies. Make an entry in the airplane logbook to show compliance with this AD.

(3) Based on the results of the inspection required in paragraph (f)(1) of this AD, if the main-gear support strut has chamfered clevis lugs, before further flight do a  Non-Destructive Inspection (NDI). Do the NDI following paragraphs 3.B. through 3.E. of PILATUS PC-7 Service Bulletin No. 32-024, Rev. No. 1, dated November 17, 2008.

(i) If cracks are found during the inspection required in paragraph (f)(3) of this AD:

                                (A) Before further flight after the inspection, replace any cracked main-gear support struts with new main-gear support struts, P/N 532.10.09.128. Do the replacement following PILATUS PC-7 Service Bulletin No. 32-025, Rev. No. 1, dated November 17, 2008.                                      ( print page 52158)    

(B) Within the next 10 days after the inspection, report the cracks to PILATUS AIRCRAFT LTD., Customer Liaison Manager, CH-6371 STANS, Switzerland, using the Crack Report Form (Figure 4) in PILATUS PC-7 Service Bulletin No. 32-024, Rev. No. 1, dated November 17, 2008. The Office of Management and Budget (OMB) approved the information collection requirements contained in this regulation under the provisions of the Paperwork Reduction Act and assigned OMB Control Number 2120-0056.

(ii) If no cracks are found during the inspection required in paragraph (f)(3) of this AD, no further action is required. Make an entry in the airplane logbook to show compliance with this AD.

(4) As of 30 days after the effective date of this AD, do not install any main-gear support struts, P/N 532.10.09.039 or P/N 114.48.07.172, with chamfered clevis lugs.

# Note 1: 

If you have any main-gear support struts, P/N 532.10.09.039 or P/N 114.48.07.172, with chamfered clevis lugs held as spares, you may return them to PILATUS AIRCRAFT LTD., Customer Liaison Manager, CH-6371 STANS, Switzerland, for replacement with a new main-gear support strut, P/N 532.10.09.128.

## FAA AD Differences

# Note 2: 

This AD differs from the MCAI and/or service information as follows: No differences.

## Other FAA AD Provisions

(g) The following provisions also apply to this AD:

                                (1)                                 *Alternative Methods of Compliance (AMOCs):*                                 The Manager, Standards 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: Doug Rudolph, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: (816) 329-4059; fax: (816) 329-4090; e-mail:                                 *doug.rudolph@faa.gov.*                                 Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.                            

                                (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.                            

                                (3)                                 *Reporting Requirements:*                                 For any reporting requirement in this AD, under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501*et seq.*), the Office of Management and Budget (OMB) has approved the information collection requirements and has assigned OMB Control Number 2120-0056.                            

## Related Information

(h) Refer to MCAI FOCA AD HB-2009-011, dated September 10, 2009; and PILATUS PC-7 Service Bulletin No. 32-024, Rev. No. 1, dated November 17, 2008; and PILATUS PC-7 Service Bulletin No. 32-025, Rev. No. 1, dated November 17, 2008, for related information.

Issued in Kansas City, Missouri, on October 5, 2009.

John Colomy,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.

[FR Doc. E9-24450 Filed 10-8-09; 8:45 am]

BILLING CODE 4910-13-P