DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-1071; Project Identifier AD-2021-01055-E]
Airworthiness Directives; Rolls-Royce Corporation Turboshaft Engines
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to supersede Airworthiness Directive
2017-18-14, which applies to certain Rolls-Royce Corporation (RRC) 250
model turboshaft engines. AD 2017-18-14 requires repetitive visual
inspections and fluorescent penetrant inspections (FPIs) of the 3rd-
stage turbine wheel and removal from service of the 4th-stage turbine
wheel. Since the FAA issued AD 2017-18-14, the manufacturer redesigned
the 3rd-stage turbine wheel. This proposed AD would require replacement
of the 3rd-stage and 4th-stage turbine wheels. This proposed AD would
also revise the applicability to add an additional turboshaft engine
model. The FAA is proposing this AD to address the unsafe condition on
DATES: The FAA must receive comments on this proposed AD by February
ADDRESSES: You may send comments, using the procedures found in
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
for submitting comments.
Fax: (202) 493-2251.
Mail: U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590.
Hand Delivery: Deliver to Mail address above between 9
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
For service information identified in this NPRM, contact Rolls-
Royce Corporation, 450 South Meridian Street, Mail Code NB-01-06,
Indianapolis, IN 46225; phone: (317) 230-2720; email:
HelicoptCustSupp@Rolls-Royce.com; website: www.rolls-royce.com. You may
view this service information at the Airworthiness Products Section,
Operational Safety Branch, FAA, 1200 District Avenue, Burlington, MA
01803. For information on the availability of this material at the FAA,
call (817) 222-5110.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-1071; 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 NPRM, any comments
received, and other information. The street address for Docket
Operations is listed above.
FOR FURTHER INFORMATION CONTACT: John Tallarovic, Aviation Safety
Engineer, Chicago ACO, FAA, 2300 E Devon Avenue, Des Plaines, IL 60018;
phone: (847) 294-8180; fax: (847) 294-7834; email: firstname.lastname@example.org.
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include ``Docket No. FAA-2021-1071; Project Identifier
AD-2021-01055-E'' at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
the proposal because of those comments.
Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact we receive about this proposed AD.
Confidential Business Information
CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as ``PROPIN.'' The FAA will treat such marked submissions as
confidential under the FOIA, and they will not be placed in the public
docket of this NPRM. Submissions containing CBI should be sent to John
Tallarovic, Aviation Safety Engineer, Chicago ACO, FAA, 2300 E. Devon
Avenue, Des Plaines, IL 60018. Any commentary that the FAA receives
which is not specifically designated as CBI will be placed in the
public docket for this rulemaking.
The FAA issued AD 2017-18-14, Amendment 39-19023 (82 FR 42443,
September 8, 2017), (AD 2017-18-14), for RRC 250-C20, -C20B, -C20F, -
C20J, -C20R, -C20R/1, -C20R/2, -C20R/4, -C20W, -C300/A1, and -C300/B1
turboshaft engines with either a 3rd-stage turbine wheel, part number
(P/N) 23065818, or a 4th-stage turbine wheel, P/N 23055944 or
RR30000240, installed. AD 2017-18-14 was prompted by in-service turbine
blade failures that revealed the need for changes to the inspections of
a certain 3rd-stage turbine wheel and removal from service of a certain
4th-stage turbine wheel. AD 2017-18-14 requires repetitive visual
inspections and FPIs of the 3rd-stage turbine wheel and removal from
service of the 4th-stage turbine wheel. AD 2017-18-14 also revises the
applicability to remove all RRC turboprop engines and adds additional
turboshaft engines. The agency issued AD 2017-18-14 to prevent failure
of the 3rd-stage and 4th-stage turbine wheel blades, damage to the
engine, and damage to the aircraft.
Actions Since AD 2017-18-14 Was Issued
Since the FAA issued AD 2017-18-14, the manufacturer redesigned the
3rd-stage turbine wheel. The manufacturer has issued Rolls-Royce (RR)
Alert Commercial Engine Bulletin (CEB) CEB A-1428/CEB A-72-4111 (single
document), specifying procedures for replacement of the 3rd-stage
turbine wheel, P/N 23065818, with the new increased blade fillet 3rd-
stage turbine wheel, P/N M250-10473. Additionally, the FAA determined
that the RRC 250-C20C (T63-A-720) model turboshaft engine is also
susceptible to the unsafe condition. The FAA, therefore, added RRC 250-
C20C (T63-A-720) model turboshaft engines to the applicability of this
proposed AD. The FAA is proposing this AD to require the replacement of
3rd-stage and 4th-stage turbine wheels with redesigned 3rd-stage and
4th-stage turbine wheels.
The FAA is issuing this NPRM after determining that the unsafe
condition described previously is likely to exist or develop on other
products of the same type design.
Related Service Information
The FAA reviewed RR Alert CEB CEB A-1428/CEB A-72-4111 (single
document), Revision 1, dated September 29, 2021. This service
information describes procedures for replacing the 3rd-stage turbine
wheel, P/N 23065818, with the new increased blade fillet 3rd-stage
turbine wheel, P/N M250-10473.
The FAA reviewed Rolls-Royce Alert CEB CEB-A-1422/CEB-A-72-4108
(single document), Original Issue, dated September 13, 2017. This
service information describes procedures for replacing 4th-stage
turbine wheel, P/N 23055944, with the new increased fillet 4th-stage
turbine wheel, P/N M250-10445.
The FAA also reviewed Rolls-Royce Alert Service Bulletin SB RR300-
A-72-024, Original Issue, dated September 13, 2017. This service
information describes procedures for replacing the 4th-stage turbine
wheel, P/N RR30000240, with the new increased fillet 4th-stage turbine
wheel, P/N RR30000494.
Proposed AD Requirements in This NPRM
This proposed AD would require removal and replacement of the 3rd-
stage and 4th-stage turbine wheels.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 3,041 3rd-stage stage turbine wheels and 3,769 4th-stage stage
turbine wheels installed on helicopters of U.S. registry.
The FAA estimates the following costs to comply with this proposed
||Cost per product
||Cost on U.S. operators
|Replace 3rd-stage turbine
wheel, P/N 23065818
||3 work-hours x $85 per hour =
||$34,743,425 (3,041 engines)
|Replace 4th-stage turbine
wheel, P/N 23055944 or RR30000240
||3 work-hours x $85 per hour =
||$34,610,727 (3,769 engines)
The FAA has included all known costs
in its cost estimate.
According to the manufacturer, however, some of the costs of this
proposed AD may be covered under warranty, thereby reducing the cost
impact on affected individuals.
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.
The FAA determined that this proposed AD would not have federalism
implications under Executive Order 13132. This proposed AD would 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 the proposed
(1) Is not a ``significant regulatory action'' under Executive
(2) Would not affect intrastate aviation in Alaska, and
(3) Would 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
The Proposed Amendment
Accordingly, under the authority delegated to me by the
Administrator, the FAA proposes to amend 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:
a. Removing Airworthiness Directive 2017-18-14, Amendment 39-19023 (82
FR 42443, September 8, 2017); and
b. Adding the following new airworthiness directive: