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###### Department of Transportation

###### Federal Aviation Administration

          - 14 CFR Part 39
          - [Docket No. FAA-2020-1074; Project Identifier MCAI-2020-01257-A; Amendment 39-21574; AD 2021-11-12]
          - RIN 2120-AA64

# AGENCY:

Federal Aviation Administration (FAA), DOT.

# ACTION:

Final rule.

# SUMMARY:

                        The FAA is adopting a new airworthiness directive (AD) for certain Pilatus Aircraft Ltd. (Pilatus) Model PC-24 airplanes. This 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 identifies the unsafe condition as the engine attachment hardware not                               ( print page 30762)                            conforming to the approved design, which could affect the structural integrity of the airplane. This AD requires inspecting the engine attachment hardware for missing washers and loose nuts and taking corrective actions as necessary. The FAA is issuing this AD to address the unsafe condition on these products.                    

# DATES:

This AD is effective July 15, 2021.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of July 15, 2021.

# ADDRESSES:

                        For service information identified in this final rule, contact Pilatus Aircraft Ltd., CH-6371, Stans, Switzerland; phone: +41 848 24 7 365; email:                         *techsupport.ch@pilatus-aircraft.com;*                         website:                         *https://www.pilatus-aircraft.com/​.*                         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 (816) 329-4148. It is also available at                         *https://www.regulations.gov*                         by searching for and locating Docket No. FAA-2020-1074.                    

## Examining the AD Docket

                    You may examine the AD docket at                     *https://www.regulations.gov*                     by searching for and locating Docket No. FAA-2020-1074; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this final rule, any comments received, and other information. The address for Docket Operations is U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE, Washington, DC 20590.                

# 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: (816) 329-4059; fax: (816) 329-4090; email:                         *doug.rudolph@faa.gov.*

# SUPPLEMENTARY INFORMATION:

## Background

                    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain serial-numbered Pilatus Model PC-24 airplanes. The NPRM published in the                     **Federal Register**                     on March 26, 2021 (86 FR 16124). The NPRM was prompted by MCAI originated by the European Union Aviation Safety Agency (EASA), which is the Technical Agent for the Member States of the European Union. EASA has issued EASA AD 2020-0194, dated September 8, 2020 (referred to after this as “the MCAI”), to address an unsafe condition on certain serial-numbered Pilatus Model PC-24 airplanes. The MCAI states:                

During a scheduled maintenance inspection, the engine attachment hardware of a PC-24 airplane was found not to conform to the approved design. A washer was missing beneath each of the four mating bolt heads on the rear engine beam. In addition, some of the keeper fitting attachment bolts on the LH/RH middle inner nacelle were found with loose nuts. It was also determined that other aeroplanes may have the same non-conformities.

This condition, if not detected and corrected, could damage the engine attachment hardware, possibly affecting the structural integrity of the aeroplane.

To address this potential unsafe condition, Pilatus issued the [service bulletin] SB, providing instructions for inspection and corrective action.

For the reason described above, this [EASA] AD requires a one-time inspection for missing washers and loose nuts on the engine attachment hardware and, depending on findings, the accomplishment of applicable corrective action(s).

                    You may examine the MCAI in the AD docket at                     *https://www.regulations.gov*                     by searching for and locating Docket No. FAA-2020-1074.                

In the NPRM, the FAA proposed to require inspecting the engine attachment hardware for missing washers and loose nuts and taking corrective actions as necessary. The FAA is issuing this AD to address the unsafe condition on this product.

## Discussion of Final Airworthiness Directive

### Comments

The FAA received no comments on the NPRM or on the determination of the costs.

### Conclusion

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, it has notified the FAA of the unsafe condition described in the MCAI and service information referenced above. The FAA reviewed the relevant data and determined that air safety and the public interest require adopting this AD as proposed. Accordingly, the FAA is issuing this AD to address the unsafe condition on these products. This AD is adopted as proposed in the NPRM.

## Related Service Information Under 1 CFR Part 51

                    The FAA reviewed Pilatus PC-24 Service Bulletin No. 71-001, dated June 30, 2020. This service information specifies procedures for inspecting the engine attachment hardware for loose nuts and missing washers and taking corrective actions depending on findings. 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                     **ADDRESSES**                    .                

## Costs of Compliance

The FAA estimates that this AD affects 34 airplanes of U.S. registry.

The FAA estimates that it would take 2.5 work-hours to do the one-time inspections. The average labor rate is $85 per work-hour.

Based on these figures, the FAA estimates the cost of this AD on U.S. operators would be $7,225 or $212.50 per airplane.

The FAA also estimates that, as on-condition costs, installing missing washers, replacing bolts, and doing an eddy current inspection of the bolt holes would take 4.5 work-hours and require parts costing $200 for a cost of $582.50 per airplane. This estimate assumes replacing all of the rear engine beam attachment bolts and washers and doing an eddy current inspection of all the attachment bolt holes. If the bolt holes are found damaged during the eddy current inspection, the damage will vary considerably from airplane to airplane, and the FAA has no way of estimating a repair cost. In addition, the FAA has no way of determining the number of airplanes that might need these actions.

The FAA has included all known costs in this cost estimate. According to the manufacturer, however, some of the costs of this AD may be covered under warranty, thereby reducing the cost impact on affected operators.

## 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                           ( print page 30763)                        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

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) 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 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.

§ 39.13

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

**2021-11-12 Pilatus Aircraft Ltd.:**                             Amendment 39-21574; Docket No. FAA-2020-1074; Project Identifier MCAI-2020-01257-A.                        

## (a) Effective Date

This airworthiness directive (AD) is effective July 15, 2021.

## (b) Affected ADs

None.

## (c) Applicability

This AD applies to Pilatus Aircraft Ltd. Model PC-24 airplanes, serial numbers (S/Ns) 101 through 162, S/N 164, S/N 165, S/N 167, and S/N 168, certificated in any category.

## (d) Subject

Joint Aircraft System Component (JASC) Code 7120, Engine Mount Section.

## (e) Unsafe Condition

This AD was prompted by 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 identifies the unsafe condition as engine attachment hardware not conforming to the approved design. The FAA is issuing this AD to detect and address incorrectly installed attachment hardware in the engine and nacelle area. The unsafe condition, if not addressed, could result in damage to the engine attachment hardware, which may affect the structural integrity of the airplane.

## (f) Actions and Compliance

Unless already done, do the actions in paragraphs (f)(1) and (2) of this AD at the next annual inspection after the effective date of this AD or within 11 months after the effective date of this AD, whichever occurs later.

(1) Inspect the left hand (LH) and right hand (RH) middle inner nacelles for loose nuts and correctly install any loose nut before further flight by following section 3.B(1) of the Accomplishment Instructions in Pilatus PC-24 Service Bulletin No. 71-001, dated June 30, 2020 (Pilatus SB 71-001).

(2) Inspect the LH and RH front and rear engine beams for missing washers by following section 3.B(2)(a) through (b) of the Accomplishment Instructions in Pilatus SB 71-001. If there are any missing washers, before further flight, do an eddy current inspection of the bolt holes for damage by following section 3.C of the Accomplishment Instructions in Pilatus SB 71-001. Where Pilatus SB 71-001 specifies obtaining repair instructions from Pilatus, the instructions must be accomplished using a method approved by the Manager, International Validation Branch, FAA; or the European Union Aviation Safety Agency (EASA); or Pilatus's EASA Design Organization Approval (DOA). If approved by the DOA, the approval must include the DOA-authorized signature.

## (g) Alternative Methods of Compliance (AMOCs)

(1) 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. If sending information directly to the manager of the International Validation Branch, send it to the attention of the person identified in Related Information.

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.

## (h) Related Information

                            (1) 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; phone: (816) 329-4059; fax: (816) 329-4090; email:                             *doug.rudolph@faa.gov.*

                            (2) Refer to EASA AD 2020-0194, dated September 8, 2020, for more information. You may examine the EASA AD at                             *https://www.regulations.gov*                             by searching for and locating Docket No. FAA-2020-1074.                        

## (i) Material Incorporated by Reference

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

(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise.

(i) Pilatus PC-24 Service Bulletin No. 71-001, dated June 30, 2020.

(ii) [Reserved]

                            (3) For Pilatus Aircraft Ltd. service information identified in this AD, contact CH-6371, Stans, Switzerland; phone: +41 848 24 7 365; email:                             *techsupport.ch@pilatus-aircraft.com;*                             website:                             *https://www.pilatus-aircraft.com/​.*

(4) You may view this service information at 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 (816) 329-4148.

                            (5) You may view this service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, email:                             *fedreg.legal@nara.gov,*                             or go to:                             *https://www.archives.gov/​federal-register/​cfr/​ibr-locations.html.*

Issued on May 17, 2021.

Lance T. Gant,

Director, Compliance & Airworthiness Division, Aircraft Certification Service.

[FR Doc. 2021-12044 Filed 6-9-21; 8:45 am]

BILLING CODE 4910-13-P