2021-19961. Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to supersede Airworthiness Directive (AD) 2012-06-16, which applies to all Pilatus Aircraft Ltd. (Pilatus) 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. AD 2012-06-16 requires installing a new rudder and elevator locking screw and modifying the installation of the rudder and elevator hinge bolt. Since the FAA issued AD 2012-06-16, the European Union Aviation Safety Agency (EASA) superseded its mandatory continuing airworthiness information (MCAI) to correct an unsafe condition on these products. This proposed AD would not retain any actions required by AD 2012-06-16 and would require inspecting and modifying the rudder, elevator, and right-hand (RH) aileron hinge bolt installations. The FAA is proposing this AD to address the unsafe condition on these products.

DATES:

The FAA must receive comments on this proposed AD by November 1, 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: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this NPRM, contact Pilatus Aircraft Ltd., Customer Support General Aviation, CH-6371 Stans, Switzerland; phone: [phone]; email: [e-mail]; 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 [phone].

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0786; 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 NPRM, the MCAI, 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 proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2021-0786; Project Identifier MCAI-2021-00429-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 NPRM.

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 NPRM 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 NPRM, 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 AD. 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 AD 2012-06-16, Amendment 39-16997 (77 FR 19061, March 30, 2012) (AD 2012-06-16) for Pilatus 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. AD 2012-06-16 was prompted by MCAI originated by EASA, which is the Technical Agent for the Member States of the European Union. EASA issued EASA AD 2011-0230, dated December 9, 2011, to identify and correct an unsafe condition identified as loose elevator and rudder hinge bolts caused by incorrect torqueing and locking of the bolts.

AD 2012-06-16 requires installing a new elevator and rudder locking screw and modifying the installation of the elevator and rudder hinge bolt. The FAA issued AD 2012-06-16 to prevent in-flight failure of the elevator or rudder attachment, which could result in loss of control of the airplane.

Actions Since AD 2012-06-16 Was Issued

Since the FAA issued AD 2012-06-16, EASA superseded EASA AD 2011-0230, dated December 9, 2011, and issued EASA AD 2021-0098, dated April 9, 2021 (referred to after this as “the MCAI”). The MCAI states:

Occurrences were reported where, on certain PC-6 aeroplanes, the elevator or the rudders was lost or partially detached during flight. All the occurrences happened on PC-6 aeroplanes in CONFIG 1.

This condition, if not corrected, could lead to in-flight failure of the elevator or rudder attachment, possibly resulting in reduced control of the aeroplane.

To address this potential unsafe condition, Pilatus issued SB 55-001 (original issue and Revision 1) to provide rework instructions for the elevator and rudder hinge bolt locking. Consequently, EASA published AD 2011-0230 to require this rework. Subsequently, Pilatus issued recommended SB 55-003 (later revised) to provide instructions to modify the hinge bolt installation of the elevator and rudder. This [service bulletin] SB, being recommended only, had no impact on the existing EASA AD.

Since that [EASA] AD and the recommended Pilatus SB 55-003 were published, the latest risk assessment determined that the modification of the hinge bolt installation of the elevator, rudder and right-hand (RH) aileron installation must be required to reach an acceptable level of safety for the affected aeroplanes. Consequently, Pilatus issued the SB, as defined in this [EASA] AD, to provide instructions to modify the affected aeroplanes into CONFIG 2 standard.

For the reasons described above, this [EASA] AD supersedes EASA AD 2011-0230 and requires, for certain aeroplanes, a one-time inspection of the elevator and rudder installation, followed by repetitive inspections of the elevator and rudder, and, depending on findings, accomplishment of applicable corrective action(s). This [EASA] AD also requires modification of the elevator, rudder and RH aileron hinge bolt installations into CONFIG 2, which is the terminating action for the repetitive inspections required by this [EASA] AD. Finally, this [EASA] AD prohibits (re)installation of affected parts.

You may examine the MCAI in the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0786.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Pilatus PC-6 Service Bulletin (SB) No. 55-005, dated February 25, 2021 (Pilatus SB 55-005). The service information specifies procedures for repetitively inspecting the hinge bolt installations and taking any necessary corrective actions until the hinge bolt is modified. Modifying the hinge bolt installation in accordance with Pilatus SB 55-005 makes the airplane a CONFIG 2 design. 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.

Other Related Service Information

Pilatus also issued Pilatus PC-6 SB No. 55-003, dated November 29, 2013; Pilatus PC-6 SB No. 55-003, Revision 1, dated December 9, 2014; Pilatus PC-6 SB No. 55-003, Revision 2, dated January 19, 2017; and Pilatus PC-6 SB No. 55-003, Revision 3, dated November 6, 2017. This service information specifies procedures for modifying the hinge bolt installations, which makes the airplane a CONFIG 2 design. This service information was superseded by Pilatus SB 55-005.

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 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 is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design.

Proposed AD Requirements in This NPRM

This proposed AD would require accomplishing the actions specified in the service information described previously. This proposed AD would not retain any actions of AD 2012-06-06.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would affect 50 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
Inspecting CONFIG 1 airplanes	4.5 work-hours × $85 per hour = $382.50	Not applicable	$382.50 per inspection cycle	$19,125 per inspection cycle.
Modifying from CONFIG 1 to CONFIG 2	14 work-hours × $85 per hour = $1,190	$1,200	$2,390	$119,500.

The FAA estimates the following costs to do any necessary corrective actions that would be required based on the results of the proposed inspection. The FAA has no way of determining the number of airplanes that might need these actions:

On-Condition Costs

Action	Labor cost	Parts cost	Cost per product
Accomplishing corrective actions	.5 work-hours × $85 per hour = $42.50	$200	$242.50

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 has 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 that the proposed regulation:

(1) Is not a “significant regulatory action” under Executive Order 12866,

(2) Would not affect intrastate aviation in Alaska, and

(3) Would 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 2012-06-16, Amendment 39-16997 ( 77 FR 19061, March 30, 2012); and

b. Adding the following new airworthiness directive:

Pilatus Aircraft Ltd.: Docket No. FAA-2021-0786; Project Identifier MCAI-2021-00429-A.

(a) Comments Due Date

The FAA must receive comments on this airworthiness directive (AD) by November 1, 2021.

(b) Affected ADs

This AD replaces AD 2012-06-16, Amendment 39-16997 (77 FR 19061, March 30, 2012).

(c) Applicability

This AD applies to Pilatus Aircraft Ltd. 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, 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

Joint Aircraft System Component (JASC) Codes 2700, Flight Control System; 2710, Aileron Control System; 2720, Rudder Control System; and 2730, Elevator Control System.

(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 describes the unsafe condition as detachment or partial detachment of the elevator or rudder in flight. The FAA is issuing this AD to prevent failure of the elevator or rudder attachment. The unsafe condition, if not addressed, could result in loss of control of the airplane.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Definitions

The following definitions apply for purposes of this AD.

(1) Group 1 airplanes: Airplanes that have not been modified in accordance with Pilatus PC-6 Service Bulletin (SB) No. 55-003, dated November 29, 2013 (Pilatus SB 55-003); Pilatus PC-6 SB No. 55-003, Revision 1, dated December 9, 2014 (Pilatus SB 55-003R1); Pilatus PC-6 SB No. 55-003, Revision 2, dated January 19, 2017 (Pilatus 55-003R2); Pilatus PC-6 SB No. 55-003, Revision 3, dated November 6, 2017 (Pilatus 55-003R3); or Pilatus PC-6 SB No. 55-005, dated February 25, 2021 (Pilatus SB 55-005).

(2) Group 2 airplanes: Airplanes that have been modified in accordance with Pilatus SB 55-003, SB 55-003R1, SB 55-003R2, Pilatus SB 55-003R3; or Pilatus SB 55-005.

(h) Inspect Elevator, Rudder, and RH Aileron Hinge Bolt Installations

(1) For Group 1 airplanes: Within 14 days after the effective date of this AD, inspect the elevator, rudder, and RH aileron hinge bolt installations and take any corrective actions before further flight by following the Accomplishment Instructions-Part 1-On Aircraft-Inspection in Pilatus SB 55-005.

(2) For Group 1 airplanes: Within 100 hours time-in-service (TIS) after the inspection required by paragraph (h)(1) of this AD and thereafter at intervals not to exceed 100 hours TIS until the modification required by paragraph (i) of this AD is done, inspect the elevator, rudder, and RH aileron hinge bolt installations and take any corrective actions before further flight by following the Accomplishment Instructions-Part 2-On Aircraft-CONFIG 1-Repeat Inspections in Pilatus SB 55-005.

(i) Modify Group 1 Airplanes

Within 11 months after the effective date of this AD, modify the hinge bolt installations on the elevator, rudder, and RH aileron assemblies by following the Accomplishment Instructions-Part 3-On Aircraft-Modification from CONFIG 1 to CONFIG 2 in Pilatus SB 55-005. Modifying the elevator, rudder, and RH aileron hinge bolt installations terminates the repetitive inspections required by paragraph (h)(2) of this AD.

(j) Installation Prohibition

As of the following applicable compliance time, do not install on any airplane an elevator assembly part number (P/N) 113.50.06.011, 113.50.06.012, 6305.0010.00, 6305.0010.52, 6305.0010.53, 6305.0010.54, or 6305.0010.55, or a rudder assembly P/N 113.40.06.018, 6302.0010.51, or 6302.0010.52.

(1) For Group 1 airplanes: As of the modification required by paragraph (i) of this AD.

(2) For Group 2 airplanes: As of the effective date of this AD.

(k) 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. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the certification office, send it to the attention of the person identified in Related Information or email: [e-mail].

(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.

(l) 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: [phone]; fax: [phone]; email: [e-mail].

(2) Refer to European Union Aviation Safety Agency (EASA) AD 2021-0098, dated April 9, 2021, for more information. You may examine the EASA AD in the AD docket at https://www.regulations.gov by searching for and locating it in Docket No. FAA-2021-0786.

(3) For service information identified in this AD, contact Pilatus Aircraft Ltd., Customer Support General Aviation, CH-6371 Stans, Switzerland; phone: [phone]; email: [e-mail]; website: https://www.pilatus-aircraft.com. You may view this referenced 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 September 9, 2021.

Lance T. Gant,

Director, Compliance & Airworthiness Division, Aircraft Certification Service.