E7-10315. Airworthiness Directives; Pilatus Aircraft Ltd. Model 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) 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 in the upper wing strut fittings of some PC-6 aircraft.

It is possible that the spherical bearing of the wing strut fittings installed in the underwing can be loose in the fitting or cannot rotate because of corrosion. In this condition, the joint cannot function as designed and fatigue cracks may then develop. Undetected cracks in this area could lead to failure of upper attachment fitting. This could result in the failure of the wing structure with 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 June 29, 2007.

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: Go to 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, 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. This 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.

This proposed AD references the MCAI and related service information that we considered in forming the engineering basis to correct the unsafe condition. The proposed AD contains text copied from the MCAI and for this reason might not follow our plain language principles.

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-2007-28157; Directorate Identifier 2007-CE-046-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 European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued AD No: 2007-0114, dated May 2, 2007 (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 in the upper wing strut fittings of some PC-6 aircraft.

It is possible that the spherical bearing of the wing strut fittings installed in the underwing can be loose in the fitting or cannot rotate because of corrosion. In this condition, the joint cannot function as designed and fatigue cracks may then develop. Undetected cracks in this area could lead to failure of upper attachment fitting. This could result in the failure of the wing structure with subsequent loss of control of the airplane. In order to correct and monitor this situation, the present AD mandates a one-time inspection of the wing strut fittings and replacement of damaged wing strut fittings with new ones. This AD also requires examination of the spherical bearings installed in the wing strut fittings and their replacement for bearings that do not pass the examination criteria.

You may obtain further information by examining the MCAI in the AD docket.

Relevant Service Information

Pilatus Aircraft Ltd. has issued Service Bulletin No. 57-004, dated April 16, 2007. 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 highlighted in a NOTE within the proposed AD.

Costs of Compliance

Based on the service information, we estimate that this proposed AD would affect about 50 products of U.S. registry. We also estimate that it would take about 7 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 $28,000, or $560 per product.

In addition, we estimate that any necessary follow-on actions would take about 15 work-hours and require parts costing $2,500 for a cost of $3,700 per fitting or $7,400 per product if both fittings are replaced. 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
• 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.: Docket No. FAA-2007-28157; Directorate Identifier 2007-CE-046-AD.

Comments Due Date

(a) We must receive comments by June 29, 2007.

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 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.

Subject

(d) Air Transport Association of America (ATA) Code 57: Wings.

Reason

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

This Airworthiness Directive (AD) is prompted due to the discovery of cracks in the upper wing strut fittings of some PC-6 aircraft.

It is possible that the spherical bearing of the wing strut fittings installed in the underwing can be loose in the fitting or cannot rotate because of corrosion. In this condition, the joint cannot function as designed and fatigue cracks may then develop. Undetected cracks in this area could lead to failure of upper attachment fitting. This could result in the failure of the wing structure with subsequent loss of control of the airplane.

In order to correct and monitor this situation, the present AD mandates a one time inspection of the wing strut fittings and replacement of damaged wing strut fittings with new ones. This AD also requires examination of the spherical bearings installed in the wing strut fittings and their replacement for bearings that do not pass the examination criteria.

Actions and Compliance

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

(1) For MSN 2001 through MSN 2092: Within the next 100 hours time-in-service (TIS) on the upper wing strut fitting after the effective date of this AD or within 3 months after the effective date of this AD, whichever occurs first, and repetitively thereafter at intervals not to exceed 12 months, do the actions specified in paragraph (f)(3) of this AD.

(2) For MSN 101 through MSN 951 do the following actions, as applicable:

(i) If the upper wing strut fitting has less than 3,500 hours TIS or has been installed for less than 84 months (7 years): Within the next 1,000 hours TIS on the upper wing strut fitting after the effective date of this AD or within 24 months after the effective date of this AD without exceeding 3,600 hours TIS or 87 months (7 years, 3 months), whichever occurs first, and repetitively thereafter at intervals not to exceed 12 months, do the actions specified in paragraph (f)(3) of this AD, or;

(ii) If the upper wing strut fitting has 3,500 or more hours TIS or has been installed for 84 months (7 years) or longer: Within the next 100 hours TIS on the upper wing strut fitting after the effective date of this AD or within 3 months after the effective date of this AD, whichever occurs first, and repetitively thereafter at intervals not to exceed 12 months, do the actions specified in paragraph (f)(3) of this AD.

Note 1:

If the TIS of the upper wing strut fittings cannot be positively determined by a review in the airplane maintenance records, then by default the upper wing strut fittings were installed from the date of original Certificate of Airworthiness.

(3) Do the following at the times specified in paragraph (f)(1) or (f)(2) of this AD:

(i) Perform a visual and non-destructive inspection of the upper wing strut fittings for cracks following the Accomplishment Instructions in Pilatus Aircraft Ltd. Service Bulletin No. 57-004, dated April 16, 2007.

(ii) Examine for conformity the spherical bearings following the Accomplishment Instructions in Pilatus Aircraft Ltd. Service Bulletin No. 57-004, dated April 16, 2007.

(4) If during any inspection required by paragraph (f)(3)(i) of this AD, cracks are found in the upper wing strut fitting, before further flight replace the wing strut fitting with a new part number (P/N) 111.35.06.185 (left side) or P/N 111.35.06.186 (right side) following the Accomplishment Instructions in Pilatus Aircraft Ltd. Service Bulletin No. 57-004, dated April 16, 2007. Replacement of the upper wing strut fitting does not terminate the repetitive inspection specified in paragraph (f)(3) of this AD.

(5) If during any inspection required by paragraph (f)(3)(ii) of this AD, the spherical bearing is found not in conformity, replace the bearing with a new P/N 944.61.00.109 following the Accomplishment Instructions in Pilatus Aircraft Ltd. Service Bulletin No. 57-004, dated April 16, 2007. Replacement of the spherical bearing does not terminate the repetitive inspection specified in paragraph (f)(3) of this AD.

(6) Report to Pilatus Aircraft Ltd. Customer Liaison Manager results of the inspection/examination using Table 1 of Pilatus Aircraft Ltd. Service Bulletin No. 57-004, dated April 16, 2007.

FAA AD Differences

Note 2:

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

(1) The FAA AD is requiring repetitive inspections and reporting results to the manufacturer, not just a one-time inspection and report as required in the MCAI.

(2) The Service Bulletin specifies “subsequent inspections for cracks 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

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

(1) Alternative Methods of Compliance (AMOCs): The Manager, Standards Staff, 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: [phone]; fax: [phone]. 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 European Aviation Safety Agency (EASA) AD No: 2007-0114, dated May 02, 2007; and Pilatus Aircraft Ltd. Service Bulletin No. 57-004, dated April 16, 2007, for related information.

Issued in Kansas City, Missouri, on May 23, 2007.

David R. Showers,

Acting Manager, Small Airplane Directorate, Aircraft Certification Service.