DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2019-1115; Project Identifier 2018-SW-065-AD; Amendment
39-21203; AD 2020-16-19]
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 two incidents of erroneous low oil
pressure caution cockpit indications and unintended actuation of the
main gearbox (MGB) auto bypass valve. This AD requires installing
auxiliary circuit breaker modification (MOD) kits and inserting a
Rotorcraft Flight Manual (RFM) Supplement into the existing RFM for
your helicopter. The FAA is issuing this AD to address the unsafe
condition on these products.

DATES: This AD is effective September 21, 2020.

The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of September 21, 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 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-2019-1115.

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-
1115; 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: Michael Schwetz, Aviation Safety
Engineer, Boston ACO Branch, FAA, 1200 District Avenue, Burlington, MA
01803; telephone 781-238-7761; email michael.schwetz@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, serial number (S/N) 920006 through 920304 inclusive and S/
N 920311 through 920314 inclusive. The NPRM published in the Federal
Register on February 18, 2020 (85 FR 8771). The NPRM was prompted by
two incidents of erroneous low oil pressure caution cockpit indications
and unintended actuation of the MGB auto bypass valve caused by
unintended popping of the M XMSN OIL WARN circuit breaker during
flight. The root cause of this circuit breaker popping is unknown. When
this circuit breaker trips, the following cautions will display "MGB
PUMP 1 FAIL, MGB PUMP 2 FAIL, MGB OIL HOT, MGB MAN COOL, MGB OIL
PRES." With the MGB auto bypass valve actuated, the MGB BYPASS caution
will not annunciate. For the given conditions, the appropriate action
for the crew is "land as soon as possible" in accordance with the RFM
Emergency Procedures. The erroneous indications conflicting with
correct gauge readings may overwhelm the flight crew, resulting in a
forced landing of the helicopter.

To address this unsafe condition, Sikorsky developed MOD kits based
on helicopter S/N to introduce a separate circuit breaker for the MGB
last jet pressure switch. These MOD kits specify reworking the overhead
panel to install new clips and brackets, circuit breaker wiring
harnesses, wiring MODs, the auxiliary circuit breaker panel, and the M
XMSN PRESS SWITCH circuit breaker. Accordingly, the NPRM proposed to
require installing MOD kits and inserting an RFM Supplement into the
existing RFM for your 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. The FAA received comments from one
commenter. The following presents the comments received on the NPRM and
the FAA's response to the comments.

Request

The commenter expressed concern about the compliance time of 400
hours time-in-service (TIS), described it as a substantial amount of
time, and suggested operators fix the problem immediately. The
commenter did not provide a technical rationale for the FAA to review.

The FAA disagrees that a shorter compliance time is required to
correct the unsafe condition. In determining that a compliance time of
400 hours TIS mitigates the risk to an acceptable level, the FAA
considered factors including Sikorsky service information, the scope of
the required actions in this AD, and
the scheduled maintenance for Sikorsky Model S-92A helicopters.

Conclusion

The FAA reviewed the relevant data, considered the comments
received, 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 Sikorsky Special Service Instructions No. 92-121,
dated October 26, 2017 (SSI 92-121). This service information describes
procedures for installing an auxiliary circuit breaker panel MOD kit
and M XMSN PRESS SWITCH circuit breaker MOD kit based on helicopter S/N.

The FAA also reviewed RFM Supplement No. 45, Revision No. 2,
Sikorsky Model S-92A, Part 1, dated April 27, 2017 (S-92A RFMS 45, Part
1, Revision 2). This service information specifies operating
limitations, preflight checks, normal and emergency procedures, and
malfunction information for helicopters with Avionics Management System
version 7.1 or 8.0 with the MGB OIL OUT warning activated, pump failure
indicating system, MGB auto bypass, and M XMSN PRESS SWITCH circuit
breaker installed.

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 reviewed Sikorsky S-92 Helicopter Alert Service Bulletin
92-63-037, Revision A, dated March 1, 2018. This service information
contains planning information pertaining to the auxiliary circuit
breaker panel and M XMSN PRESS SWITCH circuit breaker MOD kits,
accomplishing SSI 92-121, and inserting S-92A RFMS 45, Part 1, Revision
2 into the helicopter cockpit.

Costs of Compliance

The FAA estimates that this AD affects 36 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.

Modifying helicopters S/N 920006 through 920296 inclusive will take
about 48 work-hours and parts will cost about $1,618 for an estimated
cost of $5,698 per helicopter and $182,336 for the U.S. fleet size of
32 helicopters.

Modifying helicopters S/N 920297 through 920304 inclusive and S/N
920311 through 920314 inclusive will take about 2 work-hours and parts
will cost about $65 for an estimated cost of $235 per helicopter and
$940 for the U.S. fleet size of 4 helicopters.

Revising the RFM will take about 0.5 work-hour for an estimated
cost of $43 per helicopter and $1,548 for the U.S. fleet.

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

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 (AD):