[Federal Register Volume 84, Number 143 (Thursday, July 25, 2019)]
[Rules and Regulations]
[Pages 35814-35818]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2019-15757]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2016-8501; Product Identifier 2014-SW-042-AD; Amendment 
39-19678; AD 2019-13-05]
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 
certain Sikorsky Aircraft Corporation (Sikorsky) Model S-92A 
helicopters. This AD was prompted by fatigue analysis indicating stress 
concentrations, as well as the discovery of a helicopter with a crack 
in the station (STA) 362 frame and skin. This AD requires inspecting 
the main transmission forward and aft frame assemblies and adjacent 
skins for a crack and loose fasteners, and establishing life limits for 
certain frame assemblies. The FAA is issuing this AD to address the 
unsafe condition on these products.

DATES: This AD is effective August 29, 2019.

ADDRESSES: For service information identified in this final rule, 
contact Sikorsky Aircraft Corporation, Customer Service Engineering, 
124 Quarry Road, Trumbull, CT 06611; telephone 1-800-Winged-S or 203-
416-4299; email: [email protected]. 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.

Examining the AD Docket

    You may examine the AD docket on the internet at http://www.regulations.gov gov by searching for and locating Docket No. FAA-2016-
8501; 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, the regulatory evaluation, 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: Kristopher Greer, Aviation Safety 
Engineer, Boston ACO Branch, Compliance and Airworthiness

[[Page 35815]]

Division, 1200 District Avenue, Burlington, Massachusetts 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 certain Sikorsky Model 
S-92A helicopters. The NPRM published in the Federal Register on July 
15, 2016 (81 FR 46002). The NPRM was prompted by a fatigue analysis 
that indicates stress concentrations may develop at the steel doublers 
on the main transmission airframe support structure top deck, adjacent 
to the transmission feet. Additionally, a helicopter was discovered 
with a crack in the STA 362 frame and skin. The NPRM proposed to 
require inspecting the main transmission forward and aft frame 
assemblies and adjacent skins for a crack and loose fasteners, and 
replacing or repairing any cracked part or loose fastener. The NPRM 
also proposed to require establishing life limits for certain frame 
assemblies.
    The FAA issued a supplemental NPRM (SNPRM) (83 FR 66167, December 
26, 2018) that proposed to revise the NPRM by increasing the estimated 
costs of compliance and removing the daily inspection requirements.
    The FAA is issuing this AD to detect a crack in a main transmission 
airframe support structure, which could result in failure of a main 
transmission frame and subsequent loss of control of the helicopter.

Comments

    The FAA gave the public the opportunity to participate in 
developing this final rule. The following presents the comments 
received on the SNPRM and the FAA's response to each comment.

Request To Reference the Latest Service Information

    Sikorsky requested that the FAA reference the latest revision of 
Sikorsky S-92A-AMM-000 Maintenance Manual, Chapter 53-20-00, Task 53-
20-00-210-003, ``Inspection of Main Transmission Airframe Support 
Structure.''
    The FAA agrees. The FAA has revised this final rule to reference 
Sikorsky S-92A-AMM-000 Maintenance Manual, Chapter 53-20-00, Task 53-
20-00-210-003, ``Inspection of Main Transmission Airframe Support 
Structure,'' dated November 30, 2018.

Request To Revise Certain Terminology in the SNPRM

    Sikorsky requested that all instances of ``life limits'' be changed 
to ``replacement intervals.'' Sikorsky stated that this terminology is 
consistent with 14 CFR Appendix A to part 29 and the approved 
airworthiness limitations section of the maintenance manual.
    The FAA disagrees. The term ``life limit'' has been used in 
previous ADs applicable to Sikorsky aircraft and is well understood by 
the aviation industry. In addition, the use of life limit conveys the 
mandatory nature of the replacement intervals. The FAA has not changed 
this final rule in this regard.

Request To Revise the Life Limit Hours Time-In-Service (TIS) in the 
SNPRM

    Sikorsky requested that the FAA revise the values for the life 
limit hours TIS. Sikorsky stated that the replacement intervals for the 
frame assembly part numbers shown in table 1 to paragraph (e)(1) of the 
SNPRM (which is referred to as figure 1 to paragraphs (a) and (e) in 
this final rule) increased since issuance of the NPRM. Sikorsky also 
stated that a recent certification effort for these parts increased the 
replacement intervals by a minimum of 7,900 hours, to as much as 17,400 
hours, above the limits proposed in the SNPRM. Sikorsky commented that 
incorporation of these new replacement intervals (ranging from 18,300 
life limit hours TIS to 29,400 life limit hours TIS, as applicable) 
will avoid unnecessary removal from service of frame assemblies and 
avoid the need for issuance of alternate methods of compliance to 
address differences between the life limits proposed by the SNPRM and 
those subsequently approved by the FAA.
    The FAA agrees. The FAA has revised the life limits in this final 
rule for the reasons provided by the commenter because these longer 
life limits have been approved by the FAA.
    Sikorsky further commented that with approval of recent 
certification work, Forward STA 328 frame assemblies that are altered 
and changed to P/N 92070-20124-064, 92070-20124-067, 92070-20127-045, 
92070-20124-065, 92070-20124-047, or 92070-20127-046 are no longer 
counted from TIS of alternation. They are only counted from the 
original frame part number initial service date instead. These part-
numbered assemblies were proposed in the SNPRM for removal from service 
upon accumulating 12,000 hours TIS from the alteration or 28,500 hours 
TIS total (regardless of part number) from the total original frame 
part number initial service date, whichever occurs first.
    The FAA agrees and has omitted ``remove from service of upon 
accumulating 12,000 hours TIS from the alteration'' in this final rule.

Additional Changes Made in This Final Rule

    The four tables in the SNPRM have been re-identified as figures in 
this AD. The FAA has also relocated these figures to all follow 
paragraph (a) of this AD.

FAA's Determination

    The FAA has reviewed the relevant information, considered the 
comments received, and determined that an unsafe condition exists and 
is likely to exist or develop on other helicopters of the same type 
design and that air safety and the public interest require adopting the 
AD requirements as proposed with the changes described previously. 
These changes are consistent with the intent of the proposals in the 
SNPRM and do not add any additional burden upon the public than was 
already proposed in the SNPRM. Additionally, these changes will not 
increase the economic burden on any operator or increase the scope of 
the AD.

Related Service Information

    Sikorsky issued Alert Service Bulletin (ASB) 92-53-008, Basic 
Issue, dated June 13, 2012 (ASB 92-53-008); ASB 92-53-009, Basic Issue, 
dated December 6, 2012 (ASB 92-53-009); ASB 92-53-012, Basic Issue, 
dated February 10, 2014 (ASB 92-53-012); and S-92A-AMM-000 Maintenance 
Manual, Chapter 53-20-00, Task 53-20-00-210-003, ``Inspection of Main 
Transmission Airframe Support Structure,'' dated November 30, 2018 
(Task 53-20-00-210-003).
    ASB 92-53-008 provides procedures for a one-time inspection of the 
main transmission frames and beams for a crack, missing or loose 
fastener or collar, damage, deformation, and corrosion. ASB 92-53-009 
specifies, among other actions, a recurring 150-hour inspection of the 
interior and exterior surfaces of the upper flanges and beams. ASB 92-
53-012 specifies altering the forward and aft transmission support 
frames by removing steel doublers, cold-working the holes, oversizing 
the holes, trimming skin panels, and reassembling the parts with 
interference fit fasteners in accordance with Special Service 
Instructions 92-074-E. After this alteration, the parts are re-
identified with a new part number. Sikorsky refers to this alteration 
as a service life

[[Page 35816]]

extension program modification. Task 53-20-00-210-003 describes 
procedures for an inspection of the main transmission airframe support 
structure.

Differences Between This AD and the Service Information

    The service information recommends providing certain information to 
Sikorsky, and this AD does not. The service information specifies 
performing a fluorescent penetrant inspection if there is a suspected 
crack and contacting Sikorsky if there is a crack, while this AD only 
requires repairing or replacing any cracked part. Contacting Sikorsky 
is not required by this AD.

Costs of Compliance

    The FAA estimates that this AD affects 50 helicopters of U.S. 
Registry. The FAA estimates that operators may incur the following 
costs to comply with this AD. Labor costs are estimated at $85 per 
work-hour.
    The FAA estimates a minimal cost to establish and revise the life 
limit of the frame assembly. The FAA estimates it takes 1 work-hour to 
inspect STA 328 and 362 frames. No parts are needed for a total cost of 
$4,250 for the U.S. fleet for each inspection per inspection cycle. If 
a fastener is replaced, the FAA estimates the cost to be minimal. If a 
frame is replaced, it takes 5,000 work-hours and required parts cost 
$296,000 for a total cost of $721,000 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

    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 (AD):

2019-13-05 Sikorsky Aircraft Corporation: Amendment 39-19678; Docket 
No. FAA-2016-8501; Product Identifier 2014-SW-042-AD.

(a) Applicability

    This AD applies to Sikorsky Aircraft Corporation Model S-92A 
helicopters, certificated in any category, with a forward station 
(STA) 328 or aft STA 362 frame assembly with a part number (P/N) as 
shown in Figure 1 to paragraphs (a) and (e) of this AD, Figure 2 to 
paragraphs (a) and (e) of this AD, Figure 3 to paragraphs (a) and 
(e)(2) of this AD, or Figure 4 to paragraphs (a) and (e)(2) of this 
AD.
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(b) Unsafe Condition

    This AD defines the unsafe condition as a crack in a main 
transmission airframe support structure. This condition could result 
in failure of a main transmission frame and subsequent loss of 
control of the helicopter.

(c) Effective Date

    This AD is effective August 29, 2019.

(d) Compliance

    You are responsible for performing each action required by this 
AD within the specified compliance time unless it has already been 
accomplished prior to that time.

(e) Required Actions

    (1) For helicopters with a frame assembly with a part number 
shown in Figure 1 to paragraphs (a) and (e) of this AD or Figure 2 
to paragraphs (a) and (e) of this AD, before further flight, remove 
from service any part that has reached or exceeded its new life 
limit. Forward STA 328 frame assemblies that are altered and changed 
to P/N 92070-20124-064, 92070-20124-067, 92070-20127-045, 92070-
20124-065, 92070-20124-047, or 92070-20127-046 must be removed from 
service upon accumulating 28,500 hours time-in-service (TIS) total 
(regardless of P/N) from the original frame part number initial 
service date.
    (2) For each frame assembly listed in Figure 1 to paragraphs (a) 
and (e) of this AD or Figure 4 to paragraphs (a) and (e)(2) of this 
AD with 1,801 or more hours TIS, and for each frame assembly listed 
in Figure 2 to paragraphs (a) and (e) of this AD or Figure 3 to 
paragraphs (a) and (e)(2) of this AD with 1,301 or more hours TIS, 
within 150 hours TIS and thereafter at intervals not to exceed 150 
hours TIS, do the following inspections. For guidance on performing 
these inspections, refer to Sikorsky S-92A-AMM-000 Maintenance 
Manual Chapter 53-20-00, Task 53-20-00-210-003, ``Inspection of Main 
Transmission Airframe Support Structure,'' dated November 30, 2018.
    (i) Inspect the STA 328 frame and STA 362 frame between the left 
and right butt line (BL) 16.5 beams and inspect the area on the left 
and right BL 16.5 beams six inches on either side of the mounting 
pads for a crack and loose fasteners. If there is a loose fastener 
or a crack, repair or replace any cracked part and any loose 
fastener before further flight.
    (ii) Inspect the STA 328 and STA 362 outboard frames, left and 
right sides, from the BL 16.5 beam to water line 252.25 for a crack 
and loose fasteners. If there is a loose fastener or a crack, repair 
or replace any cracked part and any loose fastener before further 
flight.

(f) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, Boston ACO Branch, FAA, may approve AMOCs for 
this AD. Send your proposal to: Kristopher Greer, Aviation Safety 
Engineer, Boston ACO Branch, Compliance and Airworthiness Division, 
1200 District Avenue, Burlington, Massachusetts 01803; telephone 
(781) 238-7799; email [email protected].
    (2) For operations conducted under a 14 CFR part 119 operating 
certificate or under 14 CFR part 91, subpart K, the FAA suggests 
that you notify your principal inspector, or lacking a principal 
inspector, the manager of the local flight standards district office 
or certificate holding district office before operating any aircraft 
complying with this AD through an AMOC.

(g) Additional Information

    Sikorsky Alert Service Bulletin (ASB) 92-53-008, Basic Issue, 
dated June 13, 2012; ASB 92-53-009, Basic Issue, dated December 6, 
2012; ASB 92-53-012, Basic Issue, dated February 10, 2014, Sikorsky 
Special Service Instructions No. 92-074-E, Revision E, dated April 
9, 2014, and Sikorsky S-92A-AMM-000 Maintenance Manual, Chapter 53-
20-00, Task 53-20-00-210-003, ``Inspection of Main Transmission 
Airframe Support Structure,'' dated November 30, 2018, which are not 
incorporated by reference, contain additional information about the 
subject of this AD. For service information identified in this AD, 
contact Sikorsky Aircraft Corporation, Customer Service Engineering, 
124 Quarry Road, Trumbull, CT 06611; telephone 1-800-Winged-S or 
203-416-4299; email [email protected]. You may 
view this information at the FAA, Office of the Regional Counsel, 
Southwest Region, 10101 Hillwood Pkwy., Room 6N-321, Fort Worth, TX 
76177.

(h) Subject

    Joint Aircraft System Component (JASC) Code: 5311, Fuselage 
Main, Frame.

    Issued in Fort Worth, Texas, on July 10, 2019.
James A. Grigg,
Acting Deputy Director for Regulatory Operations, Compliance & 
Airworthiness Division, Aircraft Certification Service.
[FR Doc. 2019-15757 Filed 7-24-19; 8:45 am]
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