DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-1123; Project Identifier MCAI-2020-01294-R]
Airworthiness Directives; Airbus Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
SUMMARY: The FAA proposes to supersede Airworthiness Directive
2016-23-05, which applies to certain Airbus Helicopters Model SA-365N1,
AS-365N2, AS 365 N3, SA-366G1, EC 155B, and EC155B1 helicopters. AD
2016-23-05 requires repetitive checks of the oil level of the tail
rotor gearbox and, if necessary, filling the oil to the
maximum level; and replacement of a certain control rod double bearing
(bearing) with a new bearing. Since issuing AD 2016-23-05, the FAA has
determined additional inspections, replacements, and modifications are
necessary to address the unsafe condition. This proposed AD would
retain the requirements of AD 2016-23-05 and would add helicopters to
the applicability. This proposed AD would also require modifying the
helicopter by replacing the tail gearbox (TGB) control shaft guide
bushes; repetitive inspections of the TGB magnetic plug and corrective
actions if necessary; repetitive replacements of the bearing; and
modifying the helicopter by replacing the TGB; as specified in a
European Union Aviation Safety Agency (EASA) AD, which will be
incorporated by reference. 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 January
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
instructions for submitting comments.
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 material incorporated by reference (IBR) in this AD, contact
the 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 this IBR material on the EASA website at https://ad.easa.
europa.eu. You may view this IBR 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. It is also available in the AD
docket on the internet at https://www.regulations.gov by searching for
and locating Docket No. FAA-2020-1123.
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-2020-1123;
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. Comments will be
available in the AD docket shortly after receipt.
FOR FURTHER INFORMATION CONTACT: Kathleen Arrigotti, Aviation Safety
Engineer, Large Aircraft Section, International Validation Branch, FAA,
2200 South 216th St., Des Moines, WA 98198; telephone and fax 206-231-
3218; email email@example.com.
The FAA invites you to participate in this rulemaking by submitting
written comments, data, or views about this proposal. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. To
ensure the docket does not contain duplicate comments, commenters
should submit only one copy of the comments. Send your comments to an
address listed under the ADDRESSES section. Include "Docket No. FAA
20_2020-1123; Project Identifier MCAI-2020-01294-R" at the beginning
of your 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, as well
as a report summarizing each substantive public contact with FAA
personnel concerning this proposed rulemaking. Before acting on this
proposal, the FAA will consider all comments received by the closing
date for comments. The FAA will consider comments filed after the
comment period has closed if it is possible to do so without incurring
expense or delay. The FAA may change this NPRM because of those
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
Kathleen Arrigotti, Aviation Safety Engineer, Large Aircraft Section,
International Validation Branch, FAA, 2200 South 216th St., Des Moines,
WA 98198; telephone and fax 206-231-3218; email
firstname.lastname@example.org. 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 2016-23-05, Amendment 39-18712 (81 FR 85126,
November 25, 2016) ("AD 2016-23-05"), which applies to certain Airbus
Helicopters Model SA-365N1, AS-365N2, AS 365 N3, SA-366G1, EC 155B, and
EC155B1 helicopters. AD 2016-23-05 requires repetitive checks of the
oil level of the tail rotor gearbox and, if necessary, filling the oil
to the maximum level; and replacement of a certain bearing with a new
part-numbered bearing. The FAA issued AD 2016-23-05 to address damage
to the bearing, which could result in end play, loss of tail rotor
pitch control, and subsequent loss of control of the helicopter.
Actions Since AD 2016-23-05 Was Issued
Since the FAA issued AD 2016-23-05, the FAA has determined
additional repetitive inspections of the TGB magnetic plug for the
presence of particles (and corrective actions if necessary), repetitive
replacements of the bearing, and modifications (replacing TGB control
shaft guide bushes and replacing the TGB) are necessary to address the
The EASA, which is the Technical Agent for the Member States of the
European Union, has issued EASA AD 2017-0125, dated July 21, 2017
("EASA AD 2017-0125") (also referred to as the Mandatory Continuing
Airworthiness Information, or "the MCAI"), to correct an unsafe
condition for all Airbus Helicopters Model SA 365 N1, AS 365 N2, AS 365
N3, SA 366 G1, EC 155 B, and EC 155 B1 helicopters. EASA AD 2017-0125
supersedes EASA AD 2017-0007, dated January 13, 2017, which superseded
EASA AD 2016-0097R1, dated May 25, 2016 (which corresponds to FAA AD
2016-23-05). EASA AD 2017-0125 adds helicopters to the
applicability, adds repetitive inspections of the magnetic plug after
bearing replacement, requires the use of the revised Airbus Helicopters
Alert Service Bulletin (ASB) instructions, and requires replacement of
the TGB with a modified unit, which terminates the repetitive
This proposed AD was prompted by a determination that additional
inspections, replacements, and modifications are necessary to address
the unsafe condition. The FAA is proposing this AD to address damage to
the bearing, which could result in end play, loss of tail rotor pitch
control, and subsequent loss of control of the helicopter. See the MCAI
for additional background information.
Comments on AD 2016-23-05
The FAA gave the public the opportunity to comment on AD 2016-23-
05. The following presents the comments received on AD 2016-23-05 and
the FAA's response to each comment.
Request To Revise the Applicability To Exclude Certain TGBs
A commenter requested that the FAA revise the applicability of AD
2016-23-05 to exclude TGBs that are post-Airbus Helicopters mod 07
65B63 having part number (P/N) 365A33-6005-09. The commenter stated
that the referenced service information clarifies that only TGBs that
are pre-Airbus Helicopters mod 07 65B63 are affected.
The FAA disagrees. In developing AD 2016-23-05, the FAA differed
with EASA AD 2016-0097R1, dated May 25, 2016, and the referenced
service information. The FAA determined that TGBs that are post-Airbus
Helicopters mod 07 65B63 having P/N 365A33-6005-09 should not be
excluded from the requirements of that AD. However, the FAA notes that
the new MCAI addresses TGBs that are pre-Airbus Helicopters mod 07
65B63 and TGBs that are post-Airbus Helicopters mod 07 65B63
separately, as does this proposed AD.
Request To Revise the Applicability To Include All TGBs
A commenter requested that the FAA revise the applicability of AD
2016-23-05 to include all TGBs. The commenter stated the applicability
for AD 2016-23-05 should be the same as AD 2007-25-08, Amendment 39-
15290 (72 FR 69604, December 10, 2007), which included all bearings,
regardless of the part number of the TGB.
The FAA disagrees. In developing AD 2016-23-05, the FAA determined
the requirement to check the oil level is only necessary for
helicopters with a TGB bearing having P/N 704A33-651-093 or P/N 704A33-
651-104. However, the FAA notes that the new MCAI requires the oil
level check for all TGBs, as does this proposed AD.
Related Service Information Under 1 CFR Part 51
EASA AD 2017-0125 describes procedures for modifying the helicopter
by replacing TGB control shaft guide bushes, repetitive inspections
(checks) of the oil level of the tail rotor gearbox and, if necessary,
filling the oil to the maximum level, repetitive inspections of the TGB
magnetic plug for the presence of particles and corrective actions if
necessary (corrective actions include removing the TGB, complying with
certain work cards to address particles and other conditions such as
abrasions, scales, flakes, and splinters, and replacing the bearing),
repetitive replacements of the bearing; and modifying the helicopter by
replacing the TGB.
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.
FAA's Determination and Requirements of This Proposed AD
This product has been approved by the aviation authority of another
country, and is approved for operation in the United States. Pursuant
to the bilateral agreement with the State of Design Authority, the FAA
has been notified of the unsafe condition described in the MCAI
referenced above. The FAA is proposing this AD because the FAA
evaluated all the relevant information and determined the unsafe
condition described previously is likely to exist or develop in other
products of the same type design.
Proposed AD Requirements
This proposed AD would retain the actions required by AD 2016-23-05
and would require accomplishing the actions specified in EASA AD 2017-
0125 described previously, as incorporated by reference, except for any
differences identified as exceptions in the regulatory text of this AD
and except as discussed under "Differences Between this Proposed AD
and the MCAI."
Explanation of Required Compliance Information
In the FAA's ongoing efforts to improve the efficiency of the AD
process, the FAA initially worked with Airbus and EASA to develop a
process to use certain EASA ADs as the primary source of information
for compliance with requirements for corresponding FAA ADs. The FAA has
since coordinated with other manufacturers and civil aviation
authorities (CAAs) to use this process. As a result, EASA AD 2017-0125
will be incorporated by reference in the FAA final rule. This proposed
AD would, therefore, require compliance with EASA AD 2017-0125 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 the EASA AD 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 the EASA AD. Service information specified
in EASA AD 2017-0125 that is required for compliance with EASA AD 2017-
0125 will be available on the internet at https://www.regulations.gov
by searching for and locating Docket No. FAA-2020-1123 after the FAA
final rule is published.
Explanation of Retained Requirements
Although this proposed AD does not explicitly restate the
requirements of AD 2016-23-05, this proposed AD would retain certain
requirements of AD 2016-23-05. Those requirements are referenced in
paragraphs (2) and (5) of EASA AD 2017-0125, which, in turn, is
referenced in paragraph (g) of this proposed AD.
Costs of Compliance
The FAA estimates that this proposed AD affects 52 helicopters of
U.S. registry. The FAA estimates the following costs to comply with
this proposed AD:
Estimated Costs for Required Actions
||Cost per product
||Cost on U.S. operators
|Retained actions from AD 2016-23-05
17 work-hours x $85 per hour = $1,445
|New proposed actions
||63 work-hours x 85 per hour =
Estimated Costs for Optional Actions
|8 work-hours x $85 per hour =
The FAA has received no definitive
data that would enable the
agency to provide cost estimates for the on-condition actions specified
in this proposed AD.
According to the manufacturer, some or all of the costs of this
proposed AD may be covered under warranty, thereby reducing the cost
impact on affected operators. The FAA does not control warranty
coverage for affected operators. As a result, the FAA has included all
known costs in this cost estimate.
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 regulation:
(1) Is not a "significant regulatory action" under Executive
(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
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 removing Airworthiness Directive (AD)
2016-23-05, Amendment 39-18712 (81 FR 85126, November 25, 2016), and
adding the following new AD: