DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2022-0295; Project Identifier MCAI-2021-00840-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
for all Airbus Helicopters Model AS-365N2, AS 365 N3, EC 155B, EC155B1,
and SA-365N1 helicopters. This proposed AD was prompted by a large
amount of critical scale particles found on the tail rotor gearbox
(TGB) chip detector magnetic plug during an unscheduled check of the
TGB. The particles belonged to the double bearing (pitch control rod
bearing) installed inside the TGB. This proposed AD would require
repetitive inspections of the TGB chip detector for particles,
analyzing any particles collected, performing a double bearing washing,
repetitive replacements of certain part-numbered
double bearings, and corrective actions if necessary, as specified in
European Union Aviation Safety Agency (EASA) AD, which is proposed for
incorporation by reference (IBR). 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 May
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 EASA material that is proposed for IBR in this AD, contact
EASA, Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221
8999 000; email ADs@easa.europa.eu; internet www.easa.europa.eu. You
may find the EASA material on the EASA website at https://ad.easa.europa.eu.
You may view this material 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. The EASA material is also
available at https://www.regulations.gov by searching for and locating
Docket No. FAA-2022-0295.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2022-0295; 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 EASA AD,
any comments received, and other information. The street address for
Docket Operations is listed above.
FOR FURTHER INFORMATION CONTACT: Andrea Jimenez, Aerospace Engineer,
COS Program Management Section, Operational Safety Branch, Compliance
Airworthiness Division, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY
11590; telephone (516) 228-7330; 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-2022-0295; Project Identifier
MCAI-2021-00840-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
Andrea Jimenez, Aerospace Engineer, COS Program Management Section,
Operational Safety Branch, Compliance & Airworthiness Division, FAA,
1600 Stewart Ave., Suite 410, Westbury, NY 11590; telephone (516) 228-
7330; email email@example.com. Any commentary that the FAA
receives that 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 2021-0170, dated July 19, 2021 (EASA
AD 2021-0170), to correct an unsafe condition for all Airbus
Helicopters (AH), formerly Eurocopter, Eurocopter France, Aerospatiale,
Sud Aviation, Model AS 365 N2, AS 365 N3, EC 155 B, EC 155 B1 and SA
365 N1 helicopters.
This proposed AD was prompted by a large amount of critical scale
particles found on the TGB chip detector magnetic plug during an
unscheduled check of a Model AS 365 N2 helicopter. EASA advises the
particles belonged to the double bearing (pitch control rod bearing)
installed inside the TGB and further advises the reported event showed
a speed of degradation faster than expected. The FAA is proposing this
AD to prevent bearing degradation and subsequent failure, which could
result in loss of yaw control. See EASA AD 2021-0170 for additional
Related Service Information Under 1 CFR Part 51
EASA AD 2021-0170 requires analyzing any particles collected during
close monitoring or during any required inspections, repetitive
inspections of the TGB chip detector for particles, performing a double
bearing washing, and corrective actions. Corrective actions include
removing an affected TGB and repairing or replacing that TGB, sending
affected parts and certain information to the manufacturer, replacing
TGB chip detector or TGB electrical magnetic plug, and replacing an
affected O-ring and double bearing. EASA AD 2021-0170 also requires
performing a double bearing washing or performing a metallurgical
analysis based on inspection results.
EASA AD 2021-0170 also requires for any double bearing part number
(P/N) 704A33-651-245 or 704A33-651-246, installed on any TGB P/N
365A33-6005-09, before exceeding 610 flight hours (FH) since first
installation, or within 110 FH after October 28, 2019 (the effective
date of EASA AD 2019-0267-E, dated October 25, 2019), whichever occurs
later, and thereafter at intervals not to exceed 500 FH, replacing the
affected double bearing with a serviceable one. EASA AD 2021-0170
allows double bearing part number P/N 704A33-651-245 or 704A33-651-246
to be installed, provided it has never been installed on a helicopter
and it is inspected as required by EASA AD 2021-0170. Finally, EASA AD
2021-0170 allows TGB P/N 365A33-6005-09 to be installed, provided it
has a serviceable double bearing installed that is inspected as
required by the EASA AD.
This material 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 Airbus Helicopters Emergency Alert Service
Bulletin (EASB) No. 01.00.24 for non FAA-type certificated military
Model AS565MA, MB, MBe, SA, SB, and UB helicopters; EASB No. 01.00.71
for Model AS365N1, N2, and N3 helicopters, and non FAA-type
certificated military Model AS365F, Fi, K, and K2 helicopters; EASB No.
01.31 for non FAA-type certificated military Model SA366GA helicopters;
and EASB No. 04A016 for Model EC155B and B1 helicopters, each Revision
3 and dated June 14, 2021 (co-published as one document).
This service information specifies procedures to inspect the TGB
chip detector for particles, analyze and define the particles by
performing a metallurgical analysis, perform a washing of the double
bearing, replace the double bearing, and send certain information and
affected parts to the manufacturer.
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 the same type design.
Proposed AD Requirements in This NPRM
This proposed AD would require accomplishing the actions specified
in EASA AD 2021-0170, described previously, as incorporated by
reference, except for any differences identified as exceptions in the
regulatory text of this proposed AD and except as discussed under
``Differences Between this Proposed AD and EASA AD 2021-0170.''
Explanation of Required Compliance Information
In the FAA's ongoing efforts to improve the efficiency of the AD
process, the FAA developed a process to use some civil aviation
authority (CAA) ADs as the primary source of information for compliance
with requirements for corresponding FAA ADs. The FAA has been
coordinating this process with manufacturers and CAAs. As a result, the
FAA proposes to incorporate EASA AD 2021-0170 by reference in the FAA
final rule. This proposed AD would, therefore, require compliance with
EASA AD 2021-0170 in its entirety through that incorporation, except
for any differences identified as exceptions in the regulatory text of
this proposed AD. Using common terms that are the same as the heading
of a particular section in EASA AD 2021-0170 does not mean that
operators need comply only with that section. For example, where the AD
requirement refers to ``all required actions and compliance times,''
compliance with this AD requirement is not limited to the section
titled ``Required Action(s) and Compliance Time(s)'' in EASA AD 2021-
0170. Service information referenced in EASA AD 2021-0170 for
compliance will be available at https://www.regulations.gov by
searching for and locating Docket No. FAA-2022-0295 after the FAA final
rule is published.
Differences Between This Proposed AD and EASA AD 2021-0170
Service information referenced in EASA AD 2021-0170 specifies
sending compliance forms, and certain parts to the manufacturer; this
proposed AD would not. Service information referenced in EASA AD 2021-
0170 specifies contacting Airbus Helicopters for approved repairs or
corrective actions if certain discrepancies are found, whereas this
proposed AD would require accomplishing repairs or corrective actions
using a method approved by the Manager, General Aviation and Rotorcraft
Section, International Validation Branch, FAA; or EASA; or Airbus
Helicopters' EASA Design Organization Approval (DOA). If approved by
the DOA, the approval must include the DOA-authorized signature.
The FAA considers this proposed AD would be an interim action. If
final action is later identified, the FAA might consider further
Costs of Compliance
The FAA estimates that this AD, if adopted as proposed, would
affect 53 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.
Analyzing any particles collected during close monitoring would
take about 1 work-hour for an estimated cost of $85 per inspection and
up to $4,505 for the U.S. fleet.
Replacing a double bearing would take about 16 work-hours and parts
cost about $1,620 for an estimated cost of 2,980 per replacement and
$157,940 for the U.S. fleet.
Inspecting the TGB chip detector for particles would take about 1
work-hour for an estimated cost of $85 per inspection and $4,505 for
the U.S. fleet.
Performing a double bearing washing would take about 8 work-hours
for an estimated cost of $680 per helicopter.
The FAA estimates the following costs to do any necessary on-
condition replacements that would be required based on the results of
the inspection. The agency has no way of determining the number of
aircraft that might need these on-condition replacements:
Analyzing collected particles would take about 1 work-hour for an
estimated cost of $85 per helicopter.
Replacing a double bearing would take about 16 work-hours and parts
would cost about $1,620 for an estimated cost of $2,980 per bearing.
Replacing a TGB chip detector or TGB electrical magnetic plug would
take about 1 work-hour and parts would cost about $900 for an estimated
cost of $985 per part replacement.
Replacing an O-ring would take about 1 work-hour and parts would
cost about $100 for an estimated cost of $185 per O-ring.
Replacing a TGB would take about 8 work-hours and parts would cost
about $155,302 for an estimated cost of $155,982 per replacement.
The FAA has received no definitive data for the repair cost of a
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 this 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 adding the following new airworthiness