Document ID: FAA-2020-0792-0003
Agency: faa
Document Type: Rule
Title: Airworthiness Directives: Sikorsky Aircraft Corporation Helicopters
Posted Date: 2020-12-28T05:00Z

[Federal Register Volume 85, Number 248 (Monday, December 28, 2020)]
[Rules and Regulations]
[Pages 84201-84204]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-28385]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0792; Project Identifier 2018-SW-049-AD; Amendment 
39-21368; AD 2020-26-13]
RIN 2120-AA64

Airworthiness Directives; Sikorsky Aircraft Corporation 
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 
Sikorsky Aircraft Corporation (Sikorsky) Model S-92A helicopters. This 
AD was prompted by seven incidents of fatigue cracks in the horizontal 
stabilizer root fitting FWD (forward root fitting). This AD requires 
establishing the life limit of certain part-numbered forward root 
fittings, establishing the life limit of certain part-numbered 
stabilizer strut fittings, repetitively inspecting certain parts, and 
depending on the inspection results, removing parts from service. The 
FAA is issuing this AD to address the unsafe condition on these 
products.

DATES: This AD is effective February 1, 2021.
    The Director of the Federal Register approved the incorporation by 
reference of a certain publication listed in this AD as of February 1, 
2021.

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 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. It is also available on the internet at https://www.regulations.gov by searching for and locating Docket No. FAA-2020-
0792.

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-
0792; 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 final rule, any comments received, and other information. The 
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: Dorie Resnik, Aerospace Engineer, 
Boston ACO Branch, 1200 District Avenue, Burlington, Massachusetts 
01803; telephone 781-238-7693; email dorie.resnik@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 Sikorsky Model S-92A 
helicopters with certain part-numbered horizontal stabilizer assemblies 
(stabilizer assembly), certain part-numbered forward root fittings, or 
certain part-numbered stabilizer strut fittings installed. The NPRM 
published in the Federal Register on September 17, 2020 (85 FR 58007). 
The NPRM was prompted by seven incidents of fatigue cracks in forward 
root fittings. Fatigue cracking in a forward root fitting degrades the 
load path and increases the load on other assembly parts, particularly 
at the aft horizontal stabilizer attachment points.
    The NPRM proposed to require establishing the life limit of certain 
part-numbered forward root fittings and certain part-numbered 
stabilizer strut fittings. The NPRM also proposed to require 
repetitively inspecting each stabilizer assembly attachment bolt and 
barrel nut set, each forward root fitting, each attachment fitting 
including the bolt holes and fastener holes, condition of the 
fasteners, and each attachment fitting mating surface. Depending on the 
inspection results, the NPRM proposed to require removing parts from 
service. Finally, the NPRM proposed to prohibit installing certain 
stabilizer assemblies on any helicopter. 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 final rule, but the FAA did not receive any comments on 
the NPRM or on the determination of the cost to the public.

Conclusion

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

Related Service Information under 1 CFR Part 51

    The FAA reviewed S-92 Maintenance Manual, SA S92A-AMM-000, 
Temporary Revision (TR) 55-33, dated March 24, 2020 (TR 55-33), which 
adds additional part numbers (P/Ns) to the Horizontal Stabilizer--
Maintenance Practices and specifies procedures for inspecting each 
forward root fitting and aft root fitting bolt holes and fasteners, 
each forward and aft root fitting mating surface for wear of the 
abrasion-resistant Teflon coating, procedures for chemically striping 
the abrasion-resistant Teflon coating from the entire mounting pad, 
applying alodine, and applying an abrasion-resistant Teflon coating. 
This service information also describes procedures for removing and 
installing a stabilizer (Tasks 55-11-01-900-001 and 55-11-01-900-002), 
checking the torque stabilization (Task 55-11-01-280-001), and 
inspecting the stabilizer and attaching hardware (Task 55-11-01-210-
004). This service information also provides assembly diagrams and 
lists interchangeable stabilizer P/Ns and compatible strut P/Ns.
    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

    The FAA also reviewed S-92 Maintenance Manual SA S92A-AWL-000, TR 
No. 4-58, dated October 2, 2017 (TR 4-58), and S-92 Maintenance Manual 
SA S92A-AWL-000, TR No. 4-66 dated November 20, 2019 (TR 4-66). This 
service information revises Task 4-00-00-200-000, Table 1 Replacement 
Schedule, dated November 30, 2015. Both TR 4-58 and 4-66 revise the 
Airworthiness Limitations Schedule by removing certain part-numbered 
components, introducing new part-

[[Page 84202]]

numbered components, and establishing replacement intervals and 
recurring inspections for the forward root fitting and the horizontal 
stabilizer strut fitting. TR 4-58 also specifies inspecting the 
horizontal stabilizer and attaching hardware at a recurring interval of 
250 hours time in service (TIS).

Differences Between This AD and the Service Information

    The service information requires returning affected parts to a 
Sikorsky specialist; this AD does not.

Costs of Compliance

    The FAA estimates that this AD affects 85 helicopters of U.S. 
registry. Labor costs are estimated at $85 per work-hour. Based on 
these numbers, the FAA estimates the following costs to comply with 
this AD.
    Visually inspecting the stabilizer assembly and attached hardware 
will take about 3 work-hours for an estimated cost of $255 per 
helicopter and $21,675 for the U.S. fleet per inspection cycle.
    If required, replacing a hat bushing and both upper fittings and 
lower fittings will take about 1 work-hour and parts will cost about 
$10,000 for an estimated cost of $10,085 per replacement.
    If required, replacing the upper and lower support strut rod ends, 
including lug and conical fitting, will take about 1 work-hour and 
parts will cost about $10,000 for an estimated cost of $10,085 per 
replacement.
    If required, performing a fluorescent penetrant inspection will 
take about 3 work-hours for an estimated cost of $255 per inspection.
    If required, replacing a stabilizer assembly will take about 6 
work-hours and parts will cost about $312,000 for an estimated cost of 
$312,510 per replacement.
    If required, replacing a forward root fitting will take about 10 
work-hours and parts will cost about $25,000 for an estimated cost of 
$25,850 per replacement.
    If required, replacing a stabilizer strut fitting will take about 
10 work-hours and parts will cost about $10,000 for an estimated cost 
of $10,850 per replacement.
    If required, replacing a forward root fitting and an aft attachment 
fitting will take about 20 work-hours and parts will cost about $50,000 
for an estimated cost of $51,700 per replacement.
    If required, removing wear or corrosion and applying corrosion 
preventative compound will take about 0.5 work-hour and parts will cost 
a nominal amount for an estimated cost of $43 per action.
    If required, replacing a stabilizer attachment bolt and barrel nut 
set will take about 1 work-hour and parts will cost about $500 for an 
estimated cost of $585 per replacement.
    If required, replacing a fastener will take about 0.1 work-hour and 
parts will cost a nominal amount for an estimated cost of $9 per 
fastener.
    If required, removing the abrasion-resistant Teflon coating to 
inspect each forward and aft attachment fitting mating surface will 
take about 5 work-hours for an estimated cost of $425 per inspection.
    If required, applying alodine or equivalent and applying abrasion-
resistant Teflon coating will take about 5 work hours with minimal 
parts cost for an estimated cost of $425 per application.
    According to Sikorsky, some of the costs of this AD may be covered 
under warranty, thereby reducing the cost impact on affected 
individuals. The FAA does not control warranty coverage for affected 
individuals. As a result, the FAA has included all costs in this cost 
estimate.

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

    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

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:

2020-26-13 Sikorsky Aircraft Corporation: Amendment 39-21368; Docket 
No. FAA-2020-0792; Project Identifier 2018-SW-049-AD.

(a) Effective Date

    This airworthiness directive (AD) is effective February 1, 2021.

(b) Affected ADs

    None.

(c) Applicability

    This AD applies to Sikorsky Aircraft Corporation Model S-92A 
helicopters, certificated in any category, with the following 
installed: Horizontal stabilizer root fitting FWD (forward root 
fitting) part number (P/N) 92209-07111-101 or 92070-20125-101; or 
stabilizer strut fitting P/N 92209-07404-041, 92209-07403-041, or 
92070-20117-041 installed on horizontal stabilizer assembly 
(stabilizer assembly) P/N 92070-20117-045, 92070-20117-046, 92070-
20125-041, 92070-20125-042, 92070-20125-043, 92070-20125-044, 92205-
07400-043, or 92205-07400-045.

(d) Subject

    Joint Aircraft System Component (JASC) Code: 5510, Horizontal 
Stabilizer Structure.

(e) Unsafe Condition

    This AD was prompted by incidents of fatigue cracks in a forward 
root fitting and life limit recalculations for forward root fitting 
P/N 92209-07111-101 and 92070-20125-101. The FAA is issuing this AD 
to prevent a forward root fitting from remaining in service beyond 
its life limit, detect fatigue cracking in a forward root fitting, 
and prevent

[[Page 84203]]

increased load and stress cracking in the stabilizer root fitting 
aft. The unsafe condition, if not addressed, could result in failure 
of a stabilizer root fitting, separation of the stabilizer assembly 
from the helicopter, and subsequent loss of control of the 
helicopter.

(f) Compliance

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

(g) Required Actions

    (1) Within 50 hours time-in-service (TIS):
    (i) Determine the total hours TIS of the forward root fitting P/
N 92209-07111-101 or 92070-20125-101. If the hours TIS of the 
forward root fitting is unknown, use the hours TIS of the stabilizer 
assembly instead.
    (A) If the forward root fitting has accumulated 7,900 or more 
total hours TIS, before further flight, remove the forward root 
fitting from service.
    (B) If the forward root fitting has accumulated less than 7,900 
total hours TIS, before exceeding 7,900 hours TIS, remove the 
forward root fitting from service.
    (ii) Thereafter following paragraph (g)(1)(i) of this AD, remove 
the forward root fitting from service before accumulating 7,900 
total hours TIS.
    (iii) For stabilizer assemblies with stabilizer strut fitting P/
N 92070-20117-041 installed, perform the following actions:
    (A) Determine the total hours TIS of stabilizer strut fitting P/
N 92070-20117-041.
    (B) If the stabilizer strut fitting has accumulated 19,100 or 
more total hours TIS, before further flight, remove the stabilizer 
strut fitting from service.
    (C) If the stabilizer strut fitting has accumulated less than 
19,100 total hours TIS, before exceeding 19,100 total hours TIS, 
remove the stabilizer strut fitting from service.
    (iv) Thereafter following paragraph (g)(1)(iii) of this AD, 
remove the stabilizer strut fitting from service before accumulating 
19,100 total hours TIS.
    (2) For helicopters with stabilizer strut fitting P/N 92209-
07404-041 or 92209-07403-041 installed, within 50 hours TIS and 
thereafter at intervals not to exceed 50 hours TIS:
    (i) Remove the support strut and using a cheese cloth (or 
similar cloth) and isopropyl alcohol, clean the upper and lower 
support strut rod ends, horizontal stabilizer attachment fitting, 
and the tail rotor pylon attachment fitting.
    (ii) Using a 10X or higher power magnifying glass, a flashlight, 
and a mirror, visually inspect the hat bushing and both upper 
fittings and lower fittings for a crack, corrosion, fretting, 
deformation, and wear. If there is a crack, corrosion, fretting, 
deformation, or wear, before further flight, remove the hat bushing 
and both upper fittings and lower fittings from service.
    (iii) Using a 10X or higher power magnifying glass, a 
flashlight, and a mirror, visually inspect both upper and lower 
support strut rod ends, including lug and conical fitting, and both 
upper and lower attachment fittings on the stabilizer and pylon 
including the bushings for a crack, corrosion, fretting, 
deformation, and wear. If there is a crack, corrosion, fretting, 
deformation, or wear, before further flight, remove the upper and 
lower support strut rod ends, including lug and conical fitting, and 
both upper and lower attachment fittings on the stabilizer from 
service.
    (3) Within 250 hours TIS or one year, whichever occurs first, 
and thereafter at intervals not to exceed 250 hours TIS or one year, 
whichever occurs first:
    (i) Remove the stabilizer assembly and visually inspect each 
stabilizer attachment bolt and barrel nut set for corrosion, a 
crack, and damage to the threads. For the purposes of this 
inspection, damage may be indicated by uneven threads, missing 
threads, or cross-threading.
    (A) If there is corrosion within allowable limits, before 
further flight, treat for corrosion in accordance with FAA-approved 
procedures.
    (B) If there is corrosion that exceeds allowable limits, or a 
crack or damage to the threads, before further flight, remove the 
bolt and barrel nut set from service.
    (ii) Inspect the forward root fitting and the aft attachment 
fitting by:
    (A) Gaining access to the inside of the horizontal stabilizer.
    (B) Using Brulin Cleaner SD 1291 (or equivalent) and a low-lint 
cloth, remove all traces of sealing compound, oil, and dirt from the 
stabilizer mounting surfaces.
    (C) Using a 10X magnifying glass, inspect for any crack, wear, 
and corrosion.
    (1) If there is a crack, before further flight, remove the 
affected forward root fitting and the affected aft attachment 
fitting from service.
    (2) If there is wear or corrosion that exceeds allowable limits, 
before further flight, remove the affected forward root fitting and 
the affected aft attachment fitting from service.
    (3) If there is wear or corrosion within allowable limits, 
before further flight, treat for corrosion in accordance with FAA-
approved procedures.
    (D) Visually inspect each attachment fitting bolt hole and 
fastener hole for a crack, wear, and corrosion.
    (1) If there is a crack, before further flight, remove the 
affected forward root fitting and the affected aft attachment 
fitting from service.
    (2) If there is wear or corrosion that exceeds allowable limits, 
before further flight, remove the affected forward root fitting and 
the affected aft attachment fitting from service.
    (3) If there is wear or corrosion within allowable limits, 
before further flight, treat for corrosion in accordance with FAA 
approved procedures.
    (E) Inspect for loose or working fasteners. If there is a loose 
or working fastener, before further flight, remove the fastener from 
service.
    (iii) As an alternative means to inspect for cracks in 
paragraphs (g)(3)(i) and (ii) of this AD, perform a florescent 
penetrate inspection (FPI).
    (iv) Visually inspect each forward and aft attachment fitting 
mating surface for wear of the abrasion-resistant Teflon coating and 
degradation. For the purposes of this inspection, degradation may be 
indicated by fretting. Refer to Figure 204, of S-92 Maintenance 
Manual, SA S92A-AMM-000, Temporary Revision 55-33, Task 55-11-01-
210-004, dated March 24, 2020 (TR 55-33), for a depiction of the 
area to be inspected. For the purposes of this inspection, wear may 
be indicated by less than 100% coverage of the abrasion-resistant 
Teflon coating. If there is wear to the abrasion-resistant Teflon 
coating or degradation, before further flight:
    (A) Chemically strip the abrasion-resistant Teflon coating from 
the entire mounting pad in accordance with paragraph 7.A.(7)(a) of 
TR 55-33.
    (B) FPI or eddy current inspect for a crack. If there is a 
crack, before further flight, remove the stabilizer assembly from 
service.
    (C) If there is no crack, treat the affected area by applying 
alodine or equivalent. Apply abrasion-resistant Teflon coating in 
accordance with paragraphs 7.A.(7)(d) through (e) of TR 55-33.
    (4) Installing stabilizer strut fitting P/N 92070-20117-041 is a 
terminating action for the 50 hour TIS repetitive requirements in 
paragraph (g)(2) of this AD.
    (5) As of the effective date of this AD, do not install 
stabilizer assembly P/N 92205-07400-043, 92205-07400-045, or 92205-
07400-047 on any helicopter.

(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 (j) 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

    For more information about this AD, contact Dorie Resnik, 
Aerospace Engineer, Boston ACO Branch, 1200 District Avenue, 
Burlington, Massachusetts 01803; telephone 781-238-7693; email 
dorie.resnik@faa.gov.

(j) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (i) S-92 Maintenance Manual, SA S92A-AMM-000, Temporary Revision 
(TR) 55-33, dated March 24, 2020.
    (ii) [Reserved]
    (3) For Sikorsky Aircraft Corporation service information 
identified in this AD, contact your local Sikorsky Field 
Representative or Sikorsky's Service

[[Page 84204]]

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.
    (4) 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.
    (5) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email fedreg.legal@nara.gov, or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on December 10, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-28385 Filed 12-23-20; 8:45 am]
BILLING CODE 4910-13-P