E6-18574. Airworthiness Directives; Pilatus Aircraft Ltd., PC-6 Series Airplanes

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) issued 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 the discovery of exfoliation corrosion in the fittings of some PC-6 airplanes. These fittings are installed exterior to the bottom skin of the wing skin. If not corrected, undetected corrosion in this area could lead to failure of the fitting and subsequent loss of control of the airplane. 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 December 4, 2006.

ADDRESSES:

You may send comments by any of the following methods:

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Fax: [phone].
• Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC 20590-0001.
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.
• Federal eRulemaking Portal: http://www.regulations.gov. Follow the instructions for submitting comments.

Examining the AD Docket

You may examine the AD docket on the Internet at http://dms.dot.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 [phone]) 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 Street, Room 301, Kansas City, Missouri 64106; telephone: [phone]; fax: [phone].

SUPPLEMENTARY INFORMATION:

Streamlined Issuance of AD

The FAA is implementing a new process for streamlining the issuance of ADs related to MCAI. The streamlined process will allow us to adopt MCAI safety requirements in a more efficient manner and will reduce safety risks to the public. This process continues to follow all FAA AD issuance processes to meet legal, economic, Administrative Procedure Act, and Federal Register requirements. We also continue to meet our technical decision-making responsibilities to identify and correct unsafe conditions on U.S.-certificated products.

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-2006-25929; Directorate Identifier 2006-CE-54-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://dms.dot.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 for Civil Aviation (FOCA), which is the airworthiness authority for Switzerland, has issued FOCA AD HB-2006-400, effective date September 28, 2006 (referred to after this as “the MCAI”), to correct an unsafe condition for the specified products. The MCAI states the FOCA AD was prompted due to the discovery of exfoliation corrosion in the fittings of some PC-6 airplanes. These fittings are installed exterior to the bottom skin of the wing skin. If not corrected, undetected corrosion in this area could lead to failure of the fitting and subsequent loss of control of the airplane. In order to correct and control the situation, the MCAI requires a one time inspection of the wing strut fitting and the replacement of corroded wing strut fittings with new retrofit wing strut fittings. You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Pilatus Aircraft Ltd., has issued Service Bulletin No. 57-003, dated June 13, 2006. 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 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 described in a separate paragraph of the proposed AD. These requirements, if ultimately adopted, will take precedence over the actions copied from the MCAI.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 49 products of U.S. registry. We also estimate that it would take about 27 work-hours per product to comply with the proposed AD. The average labor rate is $80 per work-hour. Required parts would cost about $2,500 per wing, or $5,000 per product. Where the service information lists required parts costs that are covered under warranty, we have assumed that there will be no charge for these costs. As we do not control warranty coverage for affected parties, some parties may incur costs higher than estimated here. Based on these figures, we estimate the cost of the proposed AD on U.S. operators to be $350,840, or $7,160 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.

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
• 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

[Amended]

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

Pilatus Aircraft Ltd.: FAA-2006-25929; Directorate Identifier 2006-CE-54-AD

Comments Due Date

(a) We must receive comments by December 4, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Models PC-6, PC-6-H1, PC-6-H2, PC-6/350, PC-6/350-H1, PC-6/350-H2, PC-6/A, PC-6/A-H1, PC-6/A-H2, PC-6/B-H2, PC-6/B1-H2, PC-6/B2-H2, PC-6/B2-H4, PC-6/C-H2, and PC-6/C1-H2 airplanes; manufacturer serial numbers (MSN) 101 through 949, MSN 951, and MSN 2001 through 2092; that are certificated in any category. These airplanes are also identified as Fairchild Republic Company PC-6 airplanes, Fairchild Industries PC-6 airplanes, Fairchild Heli Porter PC-6 airplanes, or Fairchild-Hiller Corporation PC-6 airplanes.

Reason

(d) The Switzerland Federal Office for Civil Aviation (FOCA) Airworthiness Directive (AD) was prompted due to the discovery of exfoliation corrosion in the fittings of some PC-6 airplanes. These fittings are installed exterior to the bottom skin of the wing skin. If not corrected, undetected corrosion in this area could lead to failure of the fitting and subsequent loss of control of the airplane.

Actions and Compliance

(e) Unless already done, do the following actions.

(1) Within 12 months after the effective date of this AD and repetitively thereafter not to exceed 12 months, perform an inspection required by paragraph 3.B.(2) of PILATUS PC-6 Service Bulletin (SB) No. 57-003, dated June 13, 2006, of the fittings Part Number (P/N) 6102.0041.00, P/N 111.35.06.055 or P/N 111.35.06.056 for signs of corrosion. Minor surface corrosion is permitted according to the Repair and Overhaul Manual (ROM) (Report No. 1391), Chap. 2 and 4. Corrosion outside these limits is not permitted.

(2) If during any of the inspections required by paragraph (e)(1) of this AD, any minor surface corrosion is found, prior to further flight, remove the minor surface corrosion (Ref. ROM. Chap. 2 and 4).

(3) If during any of the inspections required by paragraph (e)(1) of this AD, any corrosion out of limits is found (Ref. ROM, Chap. 2 and 4), prior to further flight, replace the fittings in accordance with paragraph 4. of PILATUS PC-6 SB No. 57-003, dated June 13, 2006, with new (retrofit) fittings P/N 111.35.06.185 and/or P/N 111.35.06.186.

(4) Replacement of the fittings with new (improved) fittings P/N 111.35.06.185 (left hand side) and/or 111.35.06.186 (right hand side) terminates the repetitive inspection for that side.

FAA AD Differences

Note:

This AD differs from the MCAI and/or service information as follows:

(1) The FAA AD is requiring repetitive inspections, not just a one time inspection as required in the MCAI.

(2) The Service Bulletin specifies “subsequent inspection for corrosion will be included in chapter 5 of the Aircraft Maintenance Manual (AMM).” The only way we (FAA) can mandate these repetitive inspections is through an AD.

Other FAA AD Provisions

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

(1) Alternative Methods of Compliance (AMOCs): The Manager, Standards Staff, FAA, Attn: Doug Rudolph, Aerospace Engineer, FAA, Small Airplane Directorate, 901 Locust, Room 301, Kansas City, Missouri 64106; telephone: [phone]; facsimile: [phone], has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19.

(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

(g) This AD is related to FOCA AD HB-2006-400, effective date September 28, 2006, which references Pilatus Aircraft Ltd. SB No. 57-003, dated June 13, 2006.

Issued in Kansas City, Missouri, on October 27, 2006.

James E. Jackson,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.