DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0625; Product Identifier 2016-SW-007-AD; Amendment
39-21315; AD 2020-22-19]
RIN 2120-AA64

Airworthiness Directives; Various Restricted Category Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
various restricted category helicopters, originally manufactured by
Sikorsky Aircraft Corporation (Sikorsky), Model EH-60A, HH-60L, S-70,
S-70A, S-70C, S-70C(M), S-70C(M1), and UH-60A. This AD requires initial
and recurring inspections of the main rotor (M/R) blade spindle cuff
for a crack. This AD was prompted by multiple reports of a cracked M/R
blade spindle cuff. These actions are intended to prevent an unsafe
condition on these products.

DATES: This AD is effective December 3, 2020.

ADDRESSES: For service information identified in this final rule,
contact your local Sikorsky Field Representative or Sikorsky's Service
Engineering Group at Sikorsky Aircraft Corporation, 124 Quarry Road,
Trumbull, CT 06611; telephone 1-800-946-4337 (1-800-Winged-S); email
wcs_cust_service_eng.gr-sik@lmco.com. Operators may also log on to the
Sikorsky 360 website at https://www.sikorsky360.com. You may view the
referenced service information at the FAA, Office of the Regional
Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort
Worth, TX 76177.

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-
0625; 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 AD, any comments received, and other information. The street
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: Kristopher Greer, Aerospace Engineer,
Boston ACO Branch, Compliance and Airworthiness Division, FAA, 1200
District Avenue, Burlington, Massachusetts 01803; telephone 781-238-
7799; email kristopher.greer@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to various restricted
category helicopters, originally manufactured by Sikorsky, Model EH-
60A, HH-60L, S-70, S-70A, S-70C, S-70C(M), S-70C(M1), and UH-60A, with
an M/R blade spindle cuff part number 70150-09109-041 installed. The
NPRM published in the Federal Register on July 9, 2020 (85 FR 41221).
The NPRM was prompted by multiple reports of a cracked M/R blade
spindle cuff. In 2008, Sikorsky reported an M/R blade spindle cuff on a
Model UH-60A helicopter that cracked across the lower inboard bolt
holes. Investigation determined the crack was caused by a non-
conforming hole edge break, specifically a burr, introduced during an
overhaul at a non-Sikorsky overhaul facility. Sikorsky issued Sikorsky
Safety Advisory No. SSA-S70-08-002, dated December 11, 2008 (SSA-S70-
08-002), for Black Hawk Model H-60- and S-70-series helicopters to
inform operators of the incident and recommend compliance with
Sikorsky's preventative maintenance inspections. The safety advisory
also recommended that operators with M/R blades
overhauled by a non-Sikorsky repair facility contact that facility to
verify whether the hole edge radius requirement was met during the
overhaul.
In 2015, the FAA received an additional report of an M/R blade
spindle cuff on a military model helicopter that cracked. Investigation
from this reporting has revealed no anomalies at the crack initiation
site. In each instance, a crack initiated at a bolt hole and spread to
either an adjacent bolt hole or to the free edge. Due to design
similarity, Model EH-60A, HH-60L, S-70, S-70A, S-70C, S-70C(M), S-
70C(M1), and UH-60A helicopters are all affected by this unsafe
condition.
Accordingly, the NPRM proposed to require initial and recurring
inspections of the M/R blade spindle cuff for a crack. The proposed
requirements were intended to detect a crack, prevent failure of an M/R
blade spindle cuff, loss of an M/R blade, and loss of control of the
helicopter.

Comments

The FAA gave the public the opportunity to participate in
developing this final rule, but the FAA did not receive any comments on
the NPRM or on the determination of the cost to the public.

FAA's Determination

The FAA is issuing this AD after evaluating all known relevant
information and determining that an unsafe condition exists and is
likely to exist or develop on other helicopters of these same type
designs and that air safety and the public interest require adopting
the AD requirements as proposed.

Related Service Information

The FAA reviewed SSA-S70-08-002. This service information
recommends, for helicopters with M/R blades overhauled by non-Sikorsky
M/R blade repair facilities, contacting the facilities to verify
whether the hole edge radius requirement was met during cuff
replacement. The safety advisory also recommends operators conduct 10
hour/14 day visual inspections and follow the inspection procedures
regarding sudden onset of low frequency vibration or an out of track
condition.
The FAA also reviewed Sikorsky Technical Manual Preventative
Maintenance Services 10 Hour/14 Day (30 Hour/42 Day) Inspection
Checklist TM 1-70-PMS-1, dated December 1, 2014, for Sikorsky Model S-
70 helicopters. This service information contains procedures for the 10
hour/14 day and 30 hour/42 day inspections.

Costs of Compliance

The FAA estimates that this AD affects 204 helicopters of U.S.
Registry. The FAA estimates that operators may incur the following
costs in order to comply with this AD. Labor costs are estimated at $85
per work-hour.
Inspecting the M/R blade spindle cuffs takes about 1 work-hour for
an estimated cost of $85 per helicopter and $17,340 for the U.S. fleet.
Replacing an M/R blade spindle cuff takes about 175 work-hours and
required parts cost about $10,000 for a total estimated replacement
cost of $24,875 per M/R blade spindle cuff.

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 helicopters 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.

Adoption of 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.

Sec. 39.13 [Amended]

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