[Federal Register Volume 85, Number 26 (Friday, February 7, 2020)]
[Rules and Regulations]
[Pages 7191-7192]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-02446]



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 Rules and Regulations
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  Federal Register / Vol. 85, No. 26 / Friday, February 7, 2020 / Rules 
and Regulations  

[[Page 7191]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-0663; Product Identifier 2018-SW-057-AD; Amendment 
39-21025; AD 2020-02-17]
RIN 2120-AA64


Airworthiness Directives; Sikorsky Aircraft Corporation 
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
certain Sikorsky Aircraft Corporation (Sikorsky) Model S-70, S-70A, S-
70C, S-70C(M), and S-70C(M1) helicopters. This AD was prompted by four 
incidents of disbonding between the tail rotor (T/R) blade pitch horn 
and the torque tube. This AD requires recurring visual and tap 
inspections of the T/R blade, and depending on the outcome, replacing 
the T/R blade. The FAA is issuing this AD to address the unsafe 
condition on these products.

DATES: This AD is effective March 13, 2020.

ADDRESSES: For service information related to 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-Winged-S or 203-416-4299; email 
[email protected]. Operators may also log on to the 
Sikorsky 360 website at https://www.sikorsky360.com. You may view the 
related 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-2019-
0663; 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, the regulatory evaluation, any comments received, and other 
information. The street address for Docket Operations is Docket 
Operations, 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, Aviation Safety 
Engineer, Boston ACO Branch, Compliance & Airworthiness Division, FAA, 
1200 District Avenue, Burlington, MA 01803; telephone 781-238-7799; 
email [email protected].

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 Sikorsky Model S-70, S-
70A, S-70C, S-70C(M), and S-70C(M1) helicopters with T/R blade part 
number 70101-31000 (all dash numbers) and with a serial number up to 
and including A009-08915. The NPRM published in the Federal Register on 
September 6, 2019 (84 FR 46903). The NPRM was prompted by four 
incidents of disbonding between the T/R blade pitch horn and the torque 
tube on military-operated Model UH-60L and SH-60F helicopters. The 
disbonding produced minor to severe vibrations due to the mass 
imbalance. This condition may also occur on Sikorsky Model S-70, S-70A, 
S-70C, S-70C(M), and S-70C(M1) helicopters due to design similarity.
    Disbonding between the T/R blade pitch horn and the torque tube, if 
not addressed, could result in the T/R blade pitch horn rocking in the 
torque tube, leading to increased T/R vibrations. These vibrations 
could lead to crushing of the torque tube and subsequent loss of 
control of the helicopter. While Sikorsky continues to test T/R blades 
returned from the field, investigation has revealed blades produced 
prior to manufacturing improvements implemented between 2006 and 2007 
are prone to this disbonding. To address this condition, Sikorsky is 
assessing design change options to retrofit the affected T/R blades.
    The NPRM proposed to require, before the first flight of each day, 
visually inspecting each T/R blade for any crack, leading edge erosion, 
and trailing edge skin disbonding and separation, paying particular 
attention to the area from the midspan to the pitch control horn; and 
tap inspecting for disbonding in the pitch horn to torque tube bond 
area. Depending on the outcome of these inspections, the NPRM proposed 
to require replacing the T/R blade. The FAA is issuing this AD to 
address the unsafe condition on these products.

Comments

    The FAA gave the public the opportunity to participate in 
developing this AD. The FAA received no comments on the NPRM or on the 
determination of the cost to the public.

FAA's Determination

    The FAA reviewed the relevant data and determined that air safety 
and the public interest require adopting this AD as proposed.

Related Service Information

    The FAA reviewed Sikorsky Aircraft Model S-70 Blackhawk Derivatives 
Maintenance Manual Temporary Revision No. 72, dated October 12, 2017. 
This service information specifies replacing a 10-hour/14-day T/R 
inspection with a before first flight of the day T/R inspection.
    The FAA also reviewed section 5-3-13.2 Coin-Tapping Inspection 
Method of Sikorsky Technical Manual TM 1-70-23-3, Change 12, dated July 
1, 2018. This service information specifies procedures for coin-tap 
inspecting T/R blades. This service information also specifies general 
repair limits and includes figures illustrating the different types of 
materials of the T/R blade skin and core regions.

Interim Action

    The FAA considers this AD an interim action. The design approval 
holder is currently developing a modification that will address the 
unsafe condition identified in this AD. Once this modification is 
developed, approved, and available, we might consider additional 
rulemaking.

[[Page 7192]]

Costs of Compliance

    The FAA estimates that this AD affects 13 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 T/R blades takes about 1 work-hour for an estimated 
cost of $85 per helicopter and $1,105 for the U.S. fleet, per 
inspection cycle.
    Replacing a set of two T/R blades takes about 6 work-hours and 
parts cost about $192,304 for an estimated replacement cost of $192,814 
per helicopter.

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 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.
    The FAA prepared an economic evaluation of the estimated costs to 
comply with this AD and placed it in the AD docket.

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

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 (AD):

2020-02-17 Sikorsky Aircraft Corporation: Amendment 39-21025; Docket 
No. FAA-2019-0663; Product Identifier 2018-SW-057-AD.

(a) Effective Date

    This AD is effective March 13, 2020.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Model S-70, S-70A, S-70C, S-70C(M), and S-
70C(M1) helicopters, certificated in any category, with a tail rotor 
(T/R) blade part number 70101-31000 (all dash numbers) with a serial 
number (S/N) up to and including A009-08915.
    Note 1 to paragraph (c) of this AD: Each T/R blade is marked 
with the S/N.

(d) Subject

    Joint Aircraft System Component (JASC): 6410, Tail Rotor Blades.

(e) Unsafe Condition

    This AD was prompted by four incidents of disbonding between the 
T/R blade pitch horn and the torque tube. The FAA is issuing this AD 
to detect disbonding. The unsafe condition, if not addressed, could 
result in increased T/R vibrations, physical failure of the torque 
tube, and subsequent loss of control of the helicopter.

(f) Compliance

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

(g) T/R Blade Inspection

    Before the first flight of each day:
    (1) Visually inspect each T/R blade for a crack, leading edge 
erosion, and trailing edge skin disbonding and separation, paying 
particular attention to the area from the midspan to the pitch 
control horn. If there is a crack, any leading edge erosion, 
trailing edge disbonding, or trailing edge separation, before 
further flight, replace the T/R blade with an airworthy part.
    (2) Tap test inspect each T/R blade for disbonding in the pitch 
horn to torque tube bond area. If there is any disbonding, before 
further flight, replace the T/R blade with an airworthy part.

(h) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Boston 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 paragraph (i)(1) of this AD.
    (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.

(i) Related Information

    (1) For more information about this AD, contact Kristopher 
Greer, Aviation Safety Engineer, Boston ACO Branch, Compliance & 
Airworthiness Division, FAA, 1200 District Avenue, Burlington, MA 
01803; telephone 781-238-7799; email [email protected].
    (2) For service information related to this AD, 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-Winged-S or 203-416-4299; email 
[email protected]. Operators may also log on to 
the Sikorsky 360 website at https://www.sikorsky360.com. You may 
view the related 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.

    Issued in Fort Worth, Texas, on January 26, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-02446 Filed 2-6-20; 8:45 am]
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