AD 2007-19-14

We are adopting a new airworthiness directive (AD) for the products listed above that would supersede existing ADs. This AD results from mandatory continuing airworthiness information (MCAI) issued by the aviation authority of another country to identify and correct an unsafe condition on an aviation product. The MCAI describes the unsafe condition as:

Findings of corrosion, wear and cracks in the upper wing strut fittings on some PC-6 aircraft have been reported in the past.
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, wear and/or corrosion in this area could lead to failure on the upper attachment fitting. This could result in the failure of the wing structure with subsequent loss of control of the aircraft.

This AD requires actions that are intended to address the unsafe condition described in the MCAI.

Final rule; request for comments.

2007-19-14 Pilatus Aircraft Limited: Amendment 39-15205; Docket No. FAA-2007-29178; Directorate Identifier 2007-CE-074-AD.

Effective Date

(a) This airworthiness directive (AD) becomes effective September 26, 2007.

Affected ADs

(b) This AD supersedes the following ADs:
(1) AD 2007-03-08; Amendment 39-14919; and
(2) AD 2007-15-09; Amendment 39-15138.

Applicability

(c) This AD applies to:

(1) 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 (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);

(2) Manufacturer serial numbers (MSN) 101 through 999 and MSN 2001 through 2092;

(3) Airplanes that are equipped with left wing strut fitting part number (P/N) 6102.0041.00, P/N 111.35.06.055, P/N 111.35.06.184, or P/N 111.35.06.185; or equipped with right wing strut fitting P/N 6102.0041.00, P/N 111.35.06.056, P/N 111.35.06.184, or P/N 111.35.06.186, or FAA-approved equivalent part numbers; and
(4) Airplanes that are certificated in any category.

Subject

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

Reason

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

Findings of corrosion, wear and cracks in the upper wing strut fittings on some PC-6 aircraft have been reported in the past.

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, wear and/or corrosion in this area could lead to failure on the upper attachment fitting. This could result in the failure of the wingstructure with subsequent loss of control of the aircraft.

To address this problem the superseded FOCA Airworthiness Directives (AD) TM-L Nr. 80.627-6, HB-2006-400 and EASA AD 2007-0114 were issued to mandate specific inspections and to obtain a fleet status. Since the issuance of AD 2007-0114, the data reporting proved that it was necessary to establish repetitive inspections.

Thus, in addition to an extended applicability, the present AD mandates repetitive inspections of the upper wing strut fitting for cracks, wear and/or corrosion and examination of the spherical bearing and replacement of cracked fittings.

Actions and Compliance

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

(1) For airplanes that have not had both wing strut fittings replaced within the last 100 hours time-in-service (TIS) since September 26, 2007 (the effective date of this AD) or inspected using an eddy current inspection method following Pilatus Aircraft Ltd. Service Bulletin No. 57-004, dated April 16, 2007, within the last 100 hours TIS since September 26, 2007 (the effective date of this AD): Before further flight after September 26, 2007 (the effective date of this AD), visually inspect the upper wing strut fittings and examine the spherical bearings following Pilatus Aircraft Ltd. Service Bulletin No. 57-005, dated August 30, 2007.

(2) For all airplanes: Within 25 hours TIS after September 26, 2007 (the effective date of this AD) or within 30 days after September 26, 2007 (the effective date of this AD), whichever occurs first, visually and using eddy current methods, inspect the upper wing strut fittings and examine the spherical bearings following Pilatus Aircraft Ltd. Service Bulletin No. 57-005, dated August 30, 2007.

(3) For all airplanes: After doing the inspection specified in paragraph (f)(2) of this AD, repetitively at intervals not to exceed 100 hours TIS or 3 months, whichever occurs first, visually and using eddy current methods, inspect the upper wing strut fittings and examine the spherical bearings following Pilatus Aircraft Ltd. Service Bulletin No. 57-005, dated August 30, 2007.

(4) For all airplanes: If during any inspection required by paragraph (f)(1), (f)(2), or (f)(3) of this AD cracks are found in the upper wing strut fitting, before further flight, replace the wing strut fitting following the Accomplishment Instructions in Pilatus Aircraft Ltd. Service Bulletin No. 57-005, dated August 30, 2007. Replacement of one or both upper wing strut fitting(s) does not terminate the repetitive inspection specified in paragraph (f)(3) of this AD.
(5) For all airplanes: If during any inspection required by paragraph (f)(1), (f)(2), or (f)(3) of this AD the spherical bearing is found not in conformity, before further flight, replace the bearing following the Accomplishment Instructions in Pilatus Aircraft Ltd. Service Bulletin No. 57-005, dated August 30, 2007.

FAA AD Differences

Note: This AD differsfrom 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. 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: 2007-0241-E, dated September 05, 2007; Pilatus Aircraft Ltd. Service Bulletin No. 57-005, dated August 30, 2007; and Pilatus Aircraft Ltd. Service Bulletin No. 57-004, dated April 16, 2007, for related information.

Material Incorporated by Reference

(i) You must use Pilatus Aircraft Ltd. Service Bulletin No. 57- 005, dated August 30, 2007, to do the actions required by this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register approvedthe incorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) For service information identified in this AD, contact Pilatus Aircraft Ltd., Customer Liaison Manager, CH 6371 STANS, Switzerland; telephone: + 41 (0)41 619 6580; fax: + 41 (0)41 619 6576; e-mail: fodermatt@pilatus aircaft.com.

(3) You may review copies at the FAA, Central Region, Office of the Regional Counsel, 901 Locust, Room 506, Kansas City, Missouri 64106; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal-register/cfr/ibr-locations.html .

Discussion

On January 24, 2007, we issued AD 2007-03-08, Amendment 39-14919 (72 FR 4635; February 1, 2007), and on July 19, 2007, we issued AD 2007-15-09, Amendment 39-15138 (72 FR 41436; July 30, 2007). Those ADs required actions intended to address an unsafe condition on the products listed above.

Since we issued AD 2007-03-08 and AD 2007-15-09, Pilatus reported that the right hand (RH) wing strut fitting of aircraft serial number 903 was found with one lug shoulder completely broken. The aircraft had accumulated 297 hours time-in-service since the RH wing strut fitting had been replaced in May of 2007. Based on this report, the foreign airworthiness authority has issued a new MCAI.

The European Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Community, has issued AD No. 2007-0241-E, dated September 5, 2007 (referred to after this as "the MCAI''), to correct an unsafe condition for the specified products. The MCAI states:

Findings of corrosion, wear and cracks in the upper wing strut fittings on some PC-6 aircraft have been reported in the past.
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, wear and/or corrosion in this area could lead to failure on the upper attachment fitting. This could result in the failure of the wing structure with subsequent loss of control of the aircraft.

To address this problem the superseded FOCA Airworthiness Directives (AD) TM-L Nr. 80.627-6, HB-2006-400 and EASA AD 2007-0114 were issued to mandate specific inspections and to obtain a fleet status. Since the issuance of AD 2007-0114, the data reporting proved that it was necessary to establish repetitive inspections.

Thus, in addition to an extended applicability, the present AD mandates repetitive inspections of the upper wing strut fitting for cracks, wear and/or corrosion and examination of the spherical bearing and replacement of cracked 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. 57-005, dated August 30, 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 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 issuing this AD because we evaluated all information provided by the State of Design Authorityand determined the unsafe condition exists and is likely to exist or develop on other products of the same type design.

Differences Between This 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 have also required 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 AD. These requirements take precedence over those copied from the MCAI.

FAA's Determination of the Effective Date

An unsafe condition exists that requires the immediate adoption of this AD. The FAA has found that the riskto the flying public justifies waiving notice and comment prior to adoption of this rule because it is possible that fatigue cracks exist on the wing strut fittings installed on the wing that are not detected during the inspections published in the aircraft maintenance manual or required by any previous service bulletin. Undetected cracks in this area could lead to failure of the fitting and consequent loss of control. Therefore, we determined that notice and opportunity for public comment before issuing this AD are impracticable and that good cause exists for making this amendment effective in fewer than 30 days.

Comments Invited

This AD is a final rule that involves requirements affecting flight safety, and we did not precede it by notice and opportunity for public comment. We invite you to send any written relevant data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include "Docket No. FAA-2007-29178; Directorate Identifier 2007-CE-074-AD'' at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this 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 AD.

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 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); 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 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.

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.

Sec. 39.13 [Amended]

2. The FAA amends Sec. 39.13 by removing Amendment 39-14919 (72 FR 4635; February 1, 2007) and Amendment 39-15138 (72 FR 41436; July 30, 2007); and adding the following new AD: