2021-04395. Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Supplemental notice of proposed rulemaking (SNPRM).

SUMMARY:

The FAA is revising a notice of proposed rulemaking (NPRM) to supersede Airworthiness Directive (AD) 2014-25-04, which applies to all Pilatus Aircraft Ltd. (Pilatus) Model 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. This action revises the NPRM by adding an eddy current inspection of each fuselage wing fitting if an earlier version of the service information was accomplished. The FAA is proposing this AD to address the unsafe condition on these products. Since these actions would impose an additional burden over those in the NPRM, the FAA is requesting comments on this SNPRM.

DATES:

The FAA must receive comments on this SNPRM by April 22, 2021.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: [phone].
• 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, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this SNPRM, contact Pilatus Aircraft Ltd., Customer Support General Aviation, CH-6371 Stans, Switzerland; phone: [phone]; email: [e-mail]; website: https://www.pilatus-aircraft.com/​en. You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. For information on the availability of this material at the FAA, call [phone].

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-0857; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the NPRM, this SNPRM, any comments received, and other information. The street address for Docket Operations is listed above.

FOR FURTHER INFORMATION CONTACT:

Doug Rudolph, Aviation Safety Engineer, FAA, General Aviation & Rotorcraft Section, International Validation Branch, 901 Locust, Room 301, Kansas City, MO 64106; phone: [phone]; fax: [phone]; email: [e-mail].

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under ADDRESSES. Include “Docket No. FAA-2020-0857; Project Identifier MCAI-2020-00707-A” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend the proposal because of those comments.

Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to https://www.regulations.gov,, including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this proposed AD.

Confidential Business Information

CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this SNPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this SNPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this SNPRM. Submissions containing CBI should be sent to Doug Rudolph, Aviation Safety Engineer, FAA, General Aviation & Rotorcraft Section, International Validation Branch, 901 Locust, Room 301, Kansas City, MO 64106. Any commentary that the FAA receives which is not specifically designated as CBI will be placed in the public docket for this rulemaking.

Background

The FAA issued an NPRM to amend 14 CFR part 39 to supersede AD 2014-25-04, Amendment 39-18045 (79 FR 73803, December 12, 2014) (AD 2014-25-04). AD 2014-25-04 applies to all Pilatus Model 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 and resulted 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. AD 2014-25-04 requires incorporating revised airworthiness limitations into the aircraft maintenance manual (AMM) for your FAA-approved maintenance program.

The NPRM published in the Federal Register on October 2, 2020 (85 FR 62266). The NPRM was prompted by MCAI issued by the European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union. EASA superseded its previous MCAIs on this unsafe condition with EASA AD No. 2020-0120, dated May 27, 2020 (EASA AD 2020-0120). EASA AD 2020-0120 states that revised airworthiness limitations for the subject airplanes introduce new data modules that require non-destructive visual and eddy current inspections instead of a previous requirement for the fluorescent dye-penetrant method. In the NPRM, the FAA proposed to require incorporating the new airworthiness limitations (revision 29) and performing an eddy current inspection of the fuselage wing fittings and wing-to-fuselage fittings.

Actions Since the NPRM Was Issued

Since the FAA issued the NPRM, EASA superseded EASA AD 2020-0120 and issued EASA AD No. 2020-0278, dated December 14, 2020 (EASA AD 2020-0278) (also referred to after this as “the MCAI”). According to EASA AD 2020-0278, an installation procedure specified in the service information identified in the NPRM contained an error and, therefore, did not adequately address the identified unsafe condition. Pilatus has revised the airworthiness limitations (revision 30) and issued corrected service information, which includes installing certain bushes using grease instead of a bonding agent and an additional one-time eddy current inspection of the fuselage wing fittings and wing-to-fuselage fittings if the last inspection was performed using an earlier version of the service information. You may examine the MCAI in the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-0857.

This SNPRM was prompted by the FAA's determination that the revised airworthiness limitations and new inspection procedures are necessary, in addition to the new life limits proposed in the NPRM. The FAA is proposing this AD to address reduced airplane controllability due to possible loss of structural integrity of certain parts.

Comments

The FAA received a comment from Pilatus. The following presents the comment received on the NPRM and the FAA's response to that comment.

Request to Reference Latest Service Information

Pilatus requested that FAA revise the NPRM to require using Pilatus PC-6 Aircraft Maintenance Manual Document Number 01975, Revision 30, dated October 30, 2020; and Pilatus PC-6 Airworthiness Limitations Document Number 02334, Revision 10, dated October 30, 2020. In support of its request, Pilatus stated the installation procedure in the service information specified in the NPRM is incorrect. Pilatus also stated that it has added a note to the airworthiness limitations section indicating the data module procedure has been corrected and specifying a repeat of the action if it was last done in accordance with the prior service information.

The FAA agrees. After Pilatus submitted its comment, EASA issued the MCAI to require the revised service information, as described previously. In this SNPRM, the FAA proposes to require the latest service information.

Related Service Information Under 1 CFR Part 51

Pilatus issued PC-6 Airworthiness Limitations Document No. 02334, Revision 10, dated October 30, 2020; and Section 04-00-00, Airworthiness Limitations of Chapter 04, Airworthiness Limitations, of the Pilatus PC-6 Aircraft Maintenance Manual Document No. 01975, Revision 30, dated October 30, 2020. This service information contains airworthiness limitations for the stabilizer trim actuator, fuselage wing fittings, and wing-to-fuselage fittings. These documents are distinct since they apply to different airplane models.

Pilatus also issued Section 53-00-01, Fuselage Wing Fittings—Inspection/Check, of the Pilatus PC-6 Aircraft Maintenance Manual Document No. 01975, Revision 30, dated October 30, 2020; Section 57-00-03, Wing to Fuselage Fittings—Inspection/Check, of the PC-6 Aircraft Maintenance Manual Document No. 01975, Revision 29, dated February 28, 2020; Appendix K, Fuselage Wing Fittings—Inspection/Check, of the PC-6 Airworthiness Limitations Document No. 02334, Revision 10, dated October 30, 2020; and Appendix L, Wing to Fuselage Fittings—Inspection/Check, of the PC-6 Airworthiness Limitations Document No. 02334, Revision 9, dated March 6, 2020. This service information specifies procedures for repetitive eddy current inspections of the fuselage wing fittings and wing-to-fuselage fittings and, if necessary, installing the bush on the fuselage wing fittings using grease.

This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

FAA's Determination

This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to the FAA's bilateral agreement with the State of Design Authority, the FAA has been notified of the unsafe condition described in the MCAI and service information referenced above. The FAA is proposing this AD because the FAA evaluated all pertinent information and determined an unsafe condition exists and is likely to exist or develop on other products of the same type design.

Certain changes described above expand the scope of the NPRM. As a result, it is necessary to reopen the comment period to provide additional opportunity for the public to comment on this SNPRM.

Proposed Requirements of This SNPRM

This proposed AD would retain none of the requirements of AD 2014-25-04. This proposed AD would require revising the airworthiness limitation section of the existing AMM or instructions for continued airworthiness to incorporate new airworthiness limitations. The revised limitations include an eddy current inspection of the fuselage wing fittings and wing-to-fuselage fittings. This proposed AD would also require, within 50 hours time-in-service (TIS) for certain bushes, performing an eddy current inspection of the fuselage wing fittings and wing-to-fuselage fittings and replacing the bush on the fuselage wing fittings using grease. Lastly, this proposed AD would require performing the eddy current inspection of the fuselage wing fittings and wing-to-fuselage fittings first within 1,100 hours TIS or 12 months (whichever occurs first), and thereafter at the intervals specified in the revised limitations.

This proposed AD would require revisions to the airworthiness limitations section (ALS) of an operator's maintenance documents to include new inspections. Compliance with the airworthiness limitations section is required by 14 CFR 91.403(c).

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 30 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD:

Estimated Costs

Action	Labor cost	Parts cost	Cost per product	Cost on U.S. operators
ALS revision	1 work-hour × $85 per hour = $85	$0	$85	$2,550.
Eddy current inspection of the fuselage wing fittings and wing-to-fuselage fittings	7 work-hours × $85 per hour = $595	$1,860	$2,455 per inspection cycle	$73,650 per inspection cycle.

The FAA estimates the following costs to do the inspections and installation that would be required if an earlier version of the service information has been accomplished. The agency has no way of determining the number of aircraft that might need these inspections and installation:

On-Condition Costs

Action	Labor cost	Parts cost	Cost per product
Visual and eddy current inspection and installation for certain bushes	7 work-hours × $85 per hour = $595	$1,860	$2,455

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.

The FAA is 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

The FAA 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) Will not affect intrastate aviation in Alaska, 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.

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

[Amended]

2. The FAA amends § 39.13 by:

a. Removing Airworthiness Directive (AD) 2014-25-04, Amendment 39-18045 ( 79 FR 73803, December 12, 2014); and

b. Adding the following new AD:

Pilatus Aircraft Limited: Docket No. FAA-2020-0857; Project Identifier MCAI-2020-00707-A.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by April 22, 2021.

(b) Affected Airworthiness Directives (ADs)

This AD replaces AD 2014-25-04, Amendment 39-18045 (79 FR 73803, December 12, 2014) (AD 2014-25-04).

(c) Applicability

This AD applies to Pilatus Aircraft Limited Model 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, all serial numbers, certificated in any category.

Note 1 to paragraph (c):

These airplanes may also be identified as Fairchild Republic Company airplanes, Fairchild Industries airplanes, Fairchild Heli Porter airplanes, or Fairchild-Hiller Corporation airplanes.

(d) Subject

Air Transport Association (ATA) of America Code 05, Time Limits/Maintenance Checks.

(e) Reason

This AD was prompted by a determination that new and more restrictive airworthiness limitations, new life limits, and new inspection procedures are necessary. The FAA is issuing this AD to address reduced airplane controllability due to possible loss of structural integrity of certain parts.

(f) Airworthiness Limitations Revision

Unless already done, before further flight, comply with the actions specified in paragraphs (f)(1) through (3) of this AD.

(1) For Models PC-6/B2-H2 and PC-6/B2-H4 airplanes, revise the airworthiness limitations section (ALS) of the existing maintenance manual or instructions for continued airworthiness (ICA) for your airplane as follows:

(i) Replace Section 04-00-00 with Section 04-00-00, Airworthiness Limitations, of Chapter 04, Airworthiness Limitations, of the Pilatus PC-6 Aircraft Maintenance Manual Document No. 01975, Revision 30, dated October 30, 2020.

(ii) Add (or replace, if applicable) Section 53-00-01, Fuselage Wing Fittings—Inspection/Check, of the Pilatus PC-6 Aircraft Maintenance Manual Document No. 01975, Revision 30, dated October 30, 2020.

(iii) Add Section 57-00-03, Wing to Fuselage Fittings—Inspection/Check, of the Pilatus PC-6 Aircraft Maintenance Manual Document No. 01975, Revision 29, dated February 28, 2020.

(2) For all airplanes specified in paragraph (c) of this AD except Models PC-6/B2-H2 and PC-6/B2-H4 airplanes, revise the ALS of the existing maintenance manual or ICA for your airplane as follows:

(i) Replace the ALS with the Airworthiness Limitations Section of Pilatus PC-6 Airworthiness Limitations Document No. 02334, Revision 10, dated October 30, 2020.

(ii) Add (or replace, if applicable) Appendix K, Fuselage Wing Fittings—Inspection/Check, of Pilatus PC 6 Airworthiness Limitations Document No. 02334, Revision 10, dated October 30, 2020.

(iii) Add Appendix L, Wing to Fuselage Fittings—Inspection/Check, of Pilatus PC 6 Airworthiness Limitations Document No. 02334, Revision 9, dated March 6, 2020.

(3) For all airplanes specified in paragraph (c) of this AD, after revising the ALS as required by paragraphs (f)(1) and (2) of this AD, remove from service each part that has reached or exceeded its new life limit.

(g) Inspections and Replacement

(1) For airplanes with a bush part number (P/N) 6100.0020.01 that has been bonded as specified in Section 53-00-01, Fuselage Wing Fittings—Inspection/Check, of Pilatus PC-6 Aircraft Maintenance Manual Document No. 01975, Revision 29, dated February 28, 2020; or Appendix K, Fuselage Wing Fittings—Inspection/Check, of Pilatus PC-6 Airworthiness Limitations Document No. 02334, Revision 9, dated March 6, 2020: Within 50 hours time-in-service (TIS) after the effective date of this AD, perform a visual and eddy current inspection of each fuselage wing fitting on fuselage Frame 3, remove bush P/N 6100.0020.01 from service, and install a new (zero hours TIS) bush P/N 6100.0020.01 into Frame 3 with grease by using the procedures specified in paragraph (f)(1)(ii) or (f)(2)(ii) of this AD, as applicable to your airplane.

(2) Unless already done, within 1,100 hours TIS after the effective date of this AD or within 12 months after the effective date of this AD, whichever occurs first, perform an eddy current inspection of each fuselage wing fitting and each wing-to-fuselage fitting using the procedures specified in paragraphs (f)(1)(ii) and (iii) of this AD, or paragraphs (f)(2)(ii) and (iii) of this AD, as applicable to your airplane. Thereafter, repeat the eddy current inspection of each fuselage wing fitting and each wing-to-fuselage fitting at the intervals specified in the ALS identified in paragraph (f)(1)(i) or (f)(2)(i), as applicable to your airplane.

(h) No Alternative Actions or Intervals

After the ALS has been revised as required by paragraph (f) of this AD, no alternative inspection intervals or procedures may be approved, except as provided in paragraph (i) of this AD.

(i) Other FAA AD Provisions

Alternative Methods of Compliance (AMOCs): The Manager, International Validation Branch, FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send your request to the person identified in Related Information. Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspection, the manager of the local Flight Standards District Office.

(j) Related Information

(1) Refer to Mandatory Continuing Airworthiness Information (MCAI) European Union Aviation Safety Agency (EASA) AD No. 2020-0120, dated May 27, 2020, and EASA AD No. 2020-0278, dated December 14, 2020, for related information. This MCAI may be found in the AD docket on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-0857.

(2) For more information about this AD, contact Doug Rudolph, Aviation Safety Engineer, FAA, General Aviation & Rotorcraft Section, International Validation Branch, 901 Locust, Room 301, Kansas City, MO 64106; telephone: [phone]; fax: [phone]; email: [e-mail].

(3) For service information identified in this AD, contact Pilatus Aircraft Ltd., Customer Support General Aviation, CH-6371 Stans, Switzerland; telephone: [phone]; email: [e-mail]; internet: https://www.pilatusaircraft.com/​en. You may view this service information at the FAA, Airworthiness Products Section, Operational Safety Branch, 901 Locust, Kansas City, MO 64106. For information on the availability of this material at the FAA, call [phone].

Issued on February 25, 2021.

Gaetano A. Sciortino,

Deputy Director for Strategic Initiatives, Compliance & Airworthiness Division, Aircraft Certification Service.