DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-0618; Product Identifier 2019-SW-064-AD; Amendment
39-21288; AD 2020-21-15]
Airworthiness Directives; Airbus Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD)
Airbus Helicopters Model AS-365N2, AS 365 N3, EC 155B, EC155B1, and SA-
365N1 helicopters. This AD requires inspecting the tail rotor gearbox
(TGB) housing recess, and depending on the inspection results,
performing more in-depth inspections and removing certain parts from
service. This AD also prohibits installing a TGB unless it has passed
certain inspections and has a new TGB control rod bearing installed.
This AD was prompted by the discovery of a foreign object obstructing
the oil duct of a TGB control bearing. The actions of this AD are
intended to address an unsafe condition on these products.
DATES: This AD is effective December 7, 2020.
The Director of the Federal Register approved the incorporation by
reference of certain documents listed in this AD as of December 7,
ADDRESSES: For service information identified in this final rule,
contact Airbus Helicopters, 2701 N. Forum Drive, Grand Prairie, TX
75052; telephone 972-641-0000 or 800-232-0323; fax 972-641-3775; or at
may view the referenced service information at the FAA, Office of the
Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 6N-321,
Fort Worth, TX 76177. It is also available on the internet at https://www.
regulations.gov by searching for and locating Docket No. FAA-2020-0618.
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-
0618; 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 AD, the European Union Aviation Safety Agency
(EASA) AD, any service information that is incorporated by reference,
any comments received, and other information. The street 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: Rao Edupuganti, Aviation Safety
Engineer, Regulations and Policy Section, Rotorcraft Standards Branch,
FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone 817-222-
5110; email email@example.com.
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to Airbus Helicopters
Model AS-365N2, AS 365 N3, EC 155B, EC155B1, and SA-365N1 helicopters.
The NPRM published in the Federal Register on June 23, 2020 (85 FR
37591). The NPRM proposed to require opening the TGB oil filter plug
cover and removing the TGB oil filter plug, and then borescope
inspecting for oil retention and visibility of the two T holes in the
TGB housing recess. If there is any oil retention and the two T holes
are not completely visible, the NPRM proposed to require removing the
TGB control rod and inspecting for and removing any foreign object in
the TGB oil duct. The NPRM also proposed to require re-inspecting the
TGB housing recess with all of the oil drained. If, during the re-
inspection, there is any oil retention and the two T holes are not
completely visible, the NPRM proposed to require replacing the TGB. If,
during the re-inspection, there is no oil retention and the two T holes
are completely visible, the NPRM proposed to require inspecting for and
removing any foreign object from the TGB oil duct and inspecting the
TGB oil duct for correct oil flow. If the oil does not flow correctly,
the NPRM proposed to require replacing the TGB. If the oil flows
correctly, the NPRM proposed to require removing the TGB control rod
bearing from service. The NPRM also proposed to prohibit the
installation of a TGB unless it passes the proposed inspections. A non-
installed TGB would be inspected in a level position using shims.
The NPRM was prompted by EASA AD No. 2019-0165-E, dated July 12,
2019, issued by EASA, which is the Technical Agent for the Member
States of the European Union, to correct an unsafe condition for Airbus
Helicopters (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. EASA advises of a foreign object that was found
obstructing the oil duct of the TGB control bearing during a routine
inspection, causing a lack of lubrication on the bearing. EASA states
this condition, if not detected and corrected, could affect the correct
operation of the TGB and possibly result in reduced control of the
helicopter. Accordingly, the EASA AD requires a one-time inspection of
the TGB housing recess and TGB oil duct housing, and depending on the
findings, applicable investigative and corrective actions. The EASA AD
also prohibits installation of a TGB unless it has passed the specified
The FAA gave the public the opportunity to participate in
developing this final rule. The following presents the comment received
on the NPRM and the FAA's response to the comment.
A commenter asked who will be conducting the TGB inspections and
how often the inspections will take place. A mechanic that meets the
requirements of 14 CFR part 65 subpart D must perform the TGB
inspections, which are required within 55 hours time-in-service or 5
months, whichever occurs first.
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 of the
unsafe condition described in its AD. The FAA is issuing this AD after
evaluating all of the information provided by EASA and determining the
unsafe condition exists and is likely to exist or develop on other
helicopters of the same type designs and that air safety and the public
interest require adopting the AD requirements as proposed except for
updating the Costs of Compliance section due to an increase in the
number of registered helicopters. These changes are consistent with the
intent that was proposed in the NPRM for addressing the unsafe
condition and do not add any additional burden upon the public than was
already proposed in the NPRM.
Differences Between this AD and the EASA AD
If required to remove a TGB, the EASA AD requires marking and
returning the TGB to Airbus Helicopters, whereas this AD does not
require marking or returning the TGB to Airbus Helicopters.
Related Service Information Under 1 CFR Part 51
The FAA reviewed one document that co-publishes four Airbus
Helicopters Emergency Alert Service Bulletin (EASB) identification
numbers: No. 65.00.09 for non FAA-type certificated military Model
AS565MA, MB, MBe, SA, SB, and UB helicopters; No. 65.00.19 for Model
AS365N1, N2, and N3 helicopters, and non FAA-type certificated military
Model AS365F, Fi, K, and K2 helicopters; No. 65.06 for non FAA-type
certificated military Model SA366GA helicopters; and No. 65A008 for
Model EC155B and B1 helicopters, all Revision 0 and dated July 10,
2019. EASB Nos. 65.00.19 and 65A008 are incorporated by reference in
this AD. EASB Nos. 65.00.09 and 65.06 are not incorporated by reference
in this AD.
This service information specifies procedures, using an endoscope
(borescope), to inspect the TGB housing recess for oil retention and
the two T holes for visibility. If there is oil retention and the two
holes are not visible, this service information specifies removing the
TGB control rod and inspecting for and removing any foreign objects in
the TGB oil duct, and then repeating the TGB housing recess
inspections. If there is oil retention and the two T holes are not
visible after these additional inspections, the service information
specifies marking the TGB as not fit for helicopter installation and
returning the TGB to Airbus Helicopters. If there is no oil retention
and the two T holes are visible after these additional inspections, the
service information specifies removing any foreign objects in the TGB
oil duct and inspecting for proper oil flow at the end of the BTP oil
duct cover. If the oil does not flow properly, this service information
specifies marking the TGB as not fit for helicopter installation and
returning the TGB to Airbus Helicopters. If the oil flows properly, the
service information specifies replacing the TGB control rod bearing
with a new bearing.
This service information also specifies procedures to close the
filter plug cover with an airworthy O-ring, install the filter plug,
replace a TGB, and perform a ground run-up. Additionally, this service
information specifies procedures to perform the inspections on a non-
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.
Costs of Compliance
The FAA estimates that this AD affects 51 helicopters of U.S.
Registry. The FAA estimates that operators may incur the following
costs in order to comply with this AD. Labor rates are estimated at $85
Inspecting the TGB housing recess takes about 2 work-hours for an
estimated cost of $170 per helicopter and $8,670 for the U.S. fleet.
Inspecting for and removing any foreign objects takes a minimal
amount of time for a nominal cost.
Removing any oil retention and re-inspecting the TGB takes about 5
work-hours for an estimated cost of $425 per helicopter.
Inspecting for correct oil flow takes about 1 work-hour for an
estimated cost of $85 per helicopter.
Replacing the TGB control rod bearing takes about 8 work-hours and
parts cost about $2,000 for an estimated replacement cost of $2,680 per
Replacing a TGB takes about 40 work-hours and parts cost about
$48,600 (overhauled) for an estimated replacement cost of $52,000 per
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 helicopters identified in this rulemaking action.
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
(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
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