DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0189; Project Identifier AD-2020-00645-R]
RIN 2120-AA64

Airworthiness Directives; Various Restricted Category Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for type certificated Model UH-1H restricted category helicopters. This
proposed AD was prompted by multiple reports of failure of the main
driveshaft. This proposed AD would require establishing a life limit
for certain main driveshafts, and a one-time and repetitive inspections
of the main driveshafts. 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 May 10,
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 Army
Publishing Directorate, 9301 Chapek Rd., Bldg 1458, Fort Belvoir, VA
22060-5447; telephone (703) 614-3727; email usarmy.pentagon.hqda-apd.mbx.
customer-service@mail.mil; or at https://armypubs.army.mil/.

You may also contact the following as applicable:

Arrow Falcon Exporters Inc., 2081 S Wildcat Way, Porterville, CA
93257; telephone (559) 781-8604; fax (559) 781-9271; email
afe@arrowfalcon.com.

Global Helicopter Technology, Inc., P.O. Box 180681, Arlington,
Texas 76096; telephone (817) 557-3391; email ghti@ghti.net.

Hagglund Helicopters, LLC, 5101 NW A Avenue, Pendleton, OR 97801;
telephone (800) 882-3554 or (541) 276-3554; fax (541) 276-1597.

JASPP Engineering Services, LLC., 511 Harmon Terrace, Arlington, TX
76010; telephone (817) 465-4495; or at www.jjaspp.com.

Northwest Rotorcraft, LLC, 1000 85th Ave. SE, Olympia, WA 98501;
telephone (360) 754-7200; or at www.nwhelicopters.com.

Overseas Aircraft Support, Inc., P.O. Box 898, Lakeside, AZ 85929;
telephone (928) 368-6965; fax (928) 368-6962.

Richards Heavylift Helo, Inc., 1181 Osprey Nest Point, Orange Park,
FL 32073; (904) 472-1481; email Glenn7444@msn.com.

Rotorcraft Development Corporation, P.O. Box 430, Corvallis, MT
59828; telephone (207) 329-2518; email
administration@rotorcraftdevelopment.com.

Southwest Florida Aviation International, Inc., 28000-A9 Airport
Road, Bldg. 101, Punta Gorda, FL 33982-9587; telephone (941) 637-1161;
fax (941) 637-6264; email info@swfateam.org.

Tamarack Helicopters, Inc., 2849 McIntyre Rd., Stevensville, MT
59870; telephone (406) 777-0144; or at www.tamarackhelicopters.com.

You may view this service information at the FAA, Office of the
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321,
Fort Worth, TX 76177. For information on the availability of this
material at the FAA, call (817) 222-5110.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0189; 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: Matthew L. Thompson, Aerospace
Engineer, DSCO Branch, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177;
telephone (817) 222-5251; email matthew.l.thompson@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-2021-0189; Project Identifier
AD-2020-00645-R" 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 Matthew
L. Thompson, Aerospace Engineer, DSCO Branch, FAA, 10101 Hillwood Pkwy.,
Fort Worth, TX 76177; telephone (817) 222-5251; email matthew.l.thompson@
faa.gov. 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 proposes to adopt a new AD for type certificated Model UH-
1H restricted category helicopters. The type certificate holders for
these helicopters include but are not limited to Arrow Falcon Exporters
Inc.; Global Helicopter Technology, Inc.; Hagglund Helicopters, LLC;
JJASPP Engineering Services, LLC.; Northwest Rotorcraft, LLC; Overseas
Aircraft Support, Inc.; Richards Heavylift Helo, Inc.; Rotorcraft
Development Corporation; Southwest Florida Aviation International,
Inc.; and Tamarack Helicopters, Inc.

This proposed AD was prompted by multiple reports of failure of a
main driveshaft. This proposed AD would require establishing a life
limit for certain part-numbered main driveshafts, removing and
inspecting the main driveshaft, inspecting the alignment of the main
driveshaft installation, and repetitive inspections of the main
driveshaft. As an optional terminating action, this AD allows the
installation of a certain part-numbered main driveshaft not affected by
this unsafe condition. This condition, if not addressed, could result
in loss of engine power to the transmission and subsequent loss of
control of the helicopter.

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 Headquarters, Department of the Army, Aviation
Unit and Intermediate Maintenance Instructions Army Model UH-1H/V/EH-
1H/X Helicopters, Technical Manual TM 55-1520-210-23-1, Change No. 42,
dated April 14, 2003. This service information contains main driveshaft
assembly figures and specifies procedures for the main driveshaft
disassembly, cleaning, inspecting, repairing, lubricating and assembly,
installing, and inspecting and correction of its alignment.

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, before further flight after the
effective date of this AD, establishing a life limit of 5,000 hours
time-in-service (TIS) for KAflex main driveshaft part number (P/N)
SKCP2180-1, SKCP2281-1, SKCP2281-1R, and SKCP2281-103. This proposed AD
would also require, within 25 hours TIS after the effective date of
this AD, removing the main driveshaft and inspecting the main
driveshaft for any broken, loose, or missing hardware; each flex frame
and mount bolt torque stripe for movement; each joint for fretting
corrosion; the main driveshaft for damage; and the alignment of the
main driveshaft, and if required, adjusting the alignment. This
proposed AD would then require, at intervals not to exceed 300 hours
TIS, repeating the inspections with the main driveshaft installed.

As an optional terminating action, this proposed AD would allow
installing KAflex main driveshaft P/N SKCP3303-1.

Costs of Compliance

The FAA estimates that this AD, if adopted as proposed, would
affect 384 helicopters of U.S. registry. Labor rates are estimated at
$85 per work-hour. Based on these numbers, the FAA estimates that
operators may incur the following costs in order to comply with this
proposed AD.

Determining the total hours TIS of the main driveshaft would take
about 0.5 work-hour for an estimated cost of about $43 per helicopter
and $16,512 for the U.S. fleet. Removing and inspecting the main
driveshaft would take about 4 work-hours for an estimated cost of $340
per helicopter and $130,560 for the U.S. fleet. Inspecting the
installed main driveshaft would take about 1 work-hour for an estimated
cost of about $85 per helicopter and $32,640 for the U.S. fleet, per
inspection cycle. Inspecting the alignment of the main driveshaft
installation would take about 2 work-hours for an estimated cost of
$170 per helicopter and $65,280 for the U.S. fleet. If required,
adjusting the alignment would take about 0.5 work-hour for an estimated
cost of $43 per instance. Replacing a main driveshaft would take about
1 work-hour and parts would cost about $54,000, for an estimated cost
of $54,085 per replacement.

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

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 adding the following new airworthiness
directive: