[Federal Register Volume 86, Number 138 (Thursday, July 22, 2021)]
[Proposed Rules]
[Pages 38613-38615]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-15469]



[[Page 38613]]

-----------------------------------------------------------------------

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0573; Project Identifier 2018-CE-046-AD]
RIN 2120-AA64


Airworthiness Directives; Pilatus Aircraft Ltd. Airplanes

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for Pilatus Aircraft Ltd. (Pilatus) Models PC-12/45, PC-12/47, and PC-
12/47E airplanes with Supplemental Type Certificate (STC) SA00634DE 
installed. This proposed AD was prompted by a report of strake 
attachment brackets and the fuselage frame failing at the upper most 
bracket attachment location. This proposed AD would require inspecting 
the strake, attachment brackets, surrounding structure, and bolts and 
replacing components and repairing damage if necessary. 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 September 
7, 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: (202) 493-2251.
     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 
Business Aircraft Ltd., Customer Support Department, 12300 Pilatus Way, 
Broomfield, CO 80021; phone: (866) 721-2435; fax: (303) 465-9099; 
email: productsupport@pilbal.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.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0573; 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, any comments 
received, and other information. The street address for Docket 
Operations is listed above.

FOR FURTHER INFORMATION CONTACT: Richard R. Thomas, Aviation Safety 
Engineer, Denver ACO Branch, FAA, 26805 E 68th Avenue, Denver, CO 
80249; phone: (303) 342-1080; fax: (303) 342-1088; email: 9-Denver-Aircraft-Cert@faa.gov.

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-2021-0573; Project Identifier 
2018-CE-046-AD'' 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 
this 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 NPRM. Submissions containing CBI should be sent to 
Richard R. Thomas, Aviation Safety Engineer, Denver ACO Branch, FAA, 
26805 E 68th Avenue, Denver, CO 80249. 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 received a report that an operator found that one of the 
fuselage strakes was ``loose having excess play'' on two different 
Pilatus Model PC-12/47E airplanes. Further inspection found the 
fuselage main frame at frame station 40 and the strake attachment 
brackets had cracks extending from the attachment bolt hole at the 
upper most attachment location. Both airplanes had a SPECTRE Lift 
Platform System, STC SA00634DE, installed. The deployment of the lift 
platform causes buffeting of the strakes. This condition, if not 
addressed, could result in airplane flutter and reduced lateral 
stability, which may lead to loss of control of the airplane.

FAA's Determination

    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.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Pilatus Service Bulletin PC-12 Series, Report 
Number 12-1700-64-0000, Revision B, dated August 10, 2018 (Pilatus 
Report 12-1700-64-0000B), which contains procedures for inspection of 
all fuselage strake attachment bolts and the surrounding structure. 
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.

Proposed AD Requirements in This NPRM

    This proposed AD would require inspecting the strake, attachment 
brackets, and bolts for movement and damage, both internal and 
external, and replacing or repairing any damaged parts.

Differences Between This Proposed AD and the Service Information

    Pilatus Report 12-1700-64-0000B specifies a one-time inspection 
within 10 flight hours of issuance of the SB and recommends repeat 
inspections without specifying an inspection interval. This

[[Page 38614]]

proposed AD would require repeating the inspection every 150 flight 
hours. Pilatus Report 12-1700-64-0000B specifies contacting Pilatus for 
further instructions. This proposed AD would require using an FAA-
approved repair method. Pilatus Report 12-1700-64-0000B applies to 
Pilatus PC-12 aircraft serial numbers 190 to 1575. This proposed AD 
would apply to all Pilatus Aircraft Ltd. Models PC-12/45, PC-12/47, and 
PC-12/47E airplanes, regardless of serial number, if STC SA00634DE is 
installed.

Interim Action

    The FAA considers this AD an interim action. Pilatus is working on 
a modification with the intent of minimizing, if not eliminating, the 
buffeting of the strakes. Once this action is developed, approved, and 
available, the FAA may consider additional rulemaking.

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
----------------------------------------------------------------------------------------------------------------
                                                                                                  Cost on U.S.
            Action                  Labor cost            Parts cost          Cost per product      operators
----------------------------------------------------------------------------------------------------------------
Inspection of the strake        1 work-hour x $85  Not applicable..........  $85 per            $2,550 per
 assemblies.                     per hour = $85                               inspection cycle.  inspection
                                 per inspection                                                  cycle.
                                 cycle.
----------------------------------------------------------------------------------------------------------------

    The extent of damage found during the proposed inspections may vary 
considerably from airplane to airplane. The FAA has no way of knowing 
how many airplanes may have damage or the extent of damage each 
airplane may have.

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) 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

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

    Pilatus Aircraft Ltd.: Docket No. FAA-2021-0573; Project 
Identifier 2018-CE-046-AD.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by September 7, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Pilatus Aircraft Ltd. (Pilatus) Models PC-12/
45, PC-12/47, and PC-12/47E airplanes, all serial numbers, 
certificated in any category, with a Spectre Lift Platform System 
installed in accordance with Supplemental Type Certificate No. 
SA00634DE.

(d) Subject

    Joint Aircraft System Component (JASC) Code 5350, Aerodynamic 
Faring.

(e) Unsafe Condition

    This AD was prompted by a report of the strake attachment 
brackets and surrounding structure failing at the upper most bracket 
bolt hole. The FAA is issuing this AD to detect and address any 
looseness or damage to the strake, attachment brackets or 
surrounding structure, and missing fasteners or loose bolts, which 
could result in airplane flutter and reduced lateral stability, 
which may lead to loss of control of the airplane.

(f) Compliance

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

(g) Inspection and Corrective Actions

    Within 10 hours time-in-service (TIS) after the effective date 
of this AD and thereafter at intervals not to exceed 150 hours TIS, 
inspect the outside and inside fuselage strakes for movement, the 
strakes and their attachment brackets for loose and missing bolts 
and screws, and the strake attachment brackets and surrounding 
structure for discoloration, deformation, cracks, and other 
structural damage by following the Accomplishment Instructions--
Aircraft, steps A through B.(3) and C.(1) through C.(5), in Pilatus 
Service Bulletin PC-12 Series, Report Number 12-1700-64-0000, 
Revision B, dated August 10, 2018.
    (1) You must accomplish the inside fuselage inspection 
regardless of the results of the outside fuselage inspection.
    (2) If any movement of the strakes, a loose or missing bolt or 
screw, discoloration, deformation, a crack, or other structural 
damage is found during any of the inspections, before further 
flight, repair using FAA-approved procedures.

(h) Special Flight Permit

    A special flight permit may be issued to allow flying the 
airplane to a maintenance facility where repair of the strake 
assembly will be performed with the following operating limitations:

[[Page 38615]]

    (1) Flight must be conducted under visual flight rules, daytime 
only; and
    (2) The Spectre Lift Platform System, STC SA00634DE, must be 
retracted (not deployed) during the flight.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Denver ACO 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.
    (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.

(j) Related Information

    (1) For more information about this AD, contact Richard R. 
Thomas, Aviation Safety Engineer, Denver ACO Branch, FAA, 26805 E 
68th Avenue, Denver, CO 80249; phone: (303) 342-1080; fax: (303) 
342-1088; email: 9-Denver-Aircraft-Cert@faa.gov.
    (2) For service information identified in this AD, contact 
Pilatus Business Aircraft Ltd., Customer Support Department, 12300 
Pilatus Way, Broomfield, CO 80021; phone: (866) 721-2435; fax: (303) 
465-9099; email: productsupport@pilbal.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 (816) 329-4148.

    Issued on July 14, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-15469 Filed 7-21-21; 8:45 am]
BILLING CODE 4910-13-P


