DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0460; Project Identifier MCAI-2020-01620-R]
Airworthiness Directives; Airbus Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for certain Airbus Helicopters Model AS355E, AS355F, AS355F1, and
AS355F2 helicopters. This proposed AD was prompted by multiple fatigue
cracks in power turbine (PT) 3rd stage wheels. This proposed AD would
require revising the existing Rotorcraft Flight Manual (RFM) for your
helicopter and installing a placard. The FAA is proposing this AD to
address the unsafe condition on these products.
DATES: The FAA must receive comments on this proposed AD by July 26, 2021.
ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:
Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow
the instructions 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 between 9 a.m. and
5 p.m., Monday through Friday, except Federal holidays.
For Airbus Helicopters service information identified in this NPRM,
contact Airbus Helicopters, 2701 North Forum Drive, Grand Prairie, TX
75052; telephone (972) 641-0000 or (800) 232-0323; fax (972) 641-3775;
or at https://www.airbus.com/helicopters/services/technical-support.html.
For Rolls-Royce service information identified in this
NPRM, contact Rolls-Royce plc, Corporate Communications, P.O. Box 31,
Derby, DE24 8BJ, United Kingdom; phone: +44 (0)1332 242424; fax: +44
(0)1332 249936; or at https://www.rolls-royce.com/contact-us.aspx. 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.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0460; 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, the European
Union Aviation Safety Agency (EASA) AD, any comments received, and
other information. The street address for Docket Operations is listed
FOR FURTHER INFORMATION CONTACT: Michael Hughlett, Aerospace Engineer,
General Aviation & Rotorcraft Section, International Validation Branch,
FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-
5110; 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-2021-0460; Project Identifier
MCAI-2020-01620-R" 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
this 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 received about this NPRM.
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
Michael Hughlett, Aerospace Engineer, General Aviation & Rotorcraft
Section, International Validation Branch, FAA, 10101 Hillwood Pkwy.,
Fort Worth, TX 76177; telephone (817) 222-5110; email
email@example.com. Any commentary that the FAA receives which is
not specifically designated as CBI will be placed in the public docket
for this rulemaking.
EASA, which is the Technical Agent for the Member States of the
European Union, has issued EASA AD 2020-0266, dated December 8, 2020
(EASA AD 2020-0266), to correct an unsafe condition for Airbus
Helicopters (AH), formerly Eurocopter, Eurocopter France, Aerospatiale
Model AS 355 E, AS 355 F, AS 355 F1, and AS 355 F2 helicopters, all
serial numbers, if equipped with Rolls-Royce Corporation (formerly
Allison) (RRC) engine Model 250-C20F. EASA advises of multiple fatigue
cracks in PT 3rd stage wheels. Investigation has revealed that crack
initiation at the hub trailing edge could occur in low-cycle fatigue
and progress in high-cycle fatigue up to separation of the blade.
According to EASA, RRC has determined that detrimental vibrations could
occur within a particular range of turbine speeds, below the normal
operating range of this helicopter, which are a potential contributing
factor to these failures. This condition, if not addressed, could
result in fatigue failure of a PT 3rd stage wheel, and subsequent loss
of engine power, release of debris and damage to the helicopter, and
loss of control of the helicopter.
Accordingly, EASA AD 2020-0266 requires revising the Normal
Procedures Section of the applicable RFM or RFM supplement, informing flight
crews, and installing a placard in full view of both pilots.
These helicopters have been approved by EASA and are approved for
operation in the United States. Pursuant to the FAA's bilateral
agreement with the European Union, EASA has notified the FAA about the
unsafe condition described in its AD. The FAA is proposing this AD
after evaluating all known relevant information and determining that
the unsafe condition described previously is likely to exist or develop
on other helicopters of these same type designs.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Airbus Helicopters Alert Service Bulletin No.
AS355-71.00.21, Revision 1, dated November 10, 2020. This service
information specifies replacing a note with a caution in the Flight
Manual to not allow rotor speed to stagnate between 279 and 374
revolutions per minute (RPM) during engine acceleration. This service
information also specifies procedures for making and installing a label
(placard) for the pilot and co-pilot to avoid 71-95% N2 steady-state
speed (avoid operation at 279-374 RPM).
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 Rolls-Royce Alert Commercial Engine Bulletin
A-1400, Revision 7, dated January 10, 2019. This service information
specifies the speed avoidance range and operating procedures depending
on the PT wheel part number installed.
Proposed AD Requirements in This NPRM
This proposed AD would require revising the existing RFM for your
helicopter to replace a note with a caution to not allow rotor speed to
stagnate between 279 and 374 RPM. This proposed AD would also require
installing a placard to avoid 71-95% N2 steady-state speed (avoid
operation at 279-374 RPM).
Differences Between This Proposed AD and the EASA AD
EASA AD 2020-0266 requires compliance within 50 flight hours or 30
days, whichever occurs first after the effective date of its AD,
whereas this proposed AD would require compliance within 50 hours time-
in-service after the effective date of this AD instead.
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 29 helicopters of U.S. Registry. Labor rates are estimated at
$85 per work-hour. Based on these numbers, the FAA estimates the
following costs to comply with this proposed AD.
Revising the existing RFM for your helicopter would take about 0.25
work-hour for an estimated cost of $21 per helicopter and $609 for the
U.S. fleet. Installing a placard would take about 0.25 work-hour and
parts would cost a nominal amount, for an estimated cost of $21 per
helicopter and $609 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.
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, I certify this proposed regulation:
(1) Is not a "significant regulatory action" under Executive Order 12866,
(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 adding the following new airworthiness