DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0872; Project Identifier MCAI-2021-00312-R;
Amendment 39-21866; AD 2021-26-07]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2020-11-
05, which applied to all Airbus Helicopters Model EC120B helicopters.
AD 2020-11-05 required repetitive inspections of the tail rotor (TR)
hub body for cracks and applicable corrective actions if necessary, and
repetitive replacement of the attachment bolts, washers, and nuts of
the TR hub body. This AD was prompted by a report of recurrent loss of
tightening torque on several attachment bolts on the TR hub body. This
AD retains certain requirements of AD 2020-11-05, adds repetitive
inspections, requires additional corrective actions, and updates
applicable service information. The FAA is issuing this AD to address
the unsafe condition on these products.

DATES: This AD is effective January 27, 2022.

The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of January 27, 2022.

ADDRESSES: For service information identified in this final rule,
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. 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. It is also available at
https://www.regulations.gov by searching for and locating Docket No.
FAA-2021-00872.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0872; 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 final rule, the
European Union Aviation Safety Agency (EASA) AD, any comments received,
and other information. The 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: 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 andrea.jimenez@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to supersede AD 2020-11-05, Amendment 39-21130 (85 FR
31042, May 22, 2020), (AD 2020-11-05). AD 2020-11-05 applied to Airbus
Helicopters Model EC120B helicopters, all serial numbers. The NPRM
published in the Federal Register on October 8, 2021 (86 FR 56220). In
the NPRM, the FAA proposed to retain some of the requirements of AD
2020-11-05, and proposed to require, within 15 hours time-in-service
(TIS) or 7 days, whichever occurs first, performing repetitive
inspections of the TR hub body for a crack and depending on the
inspection results, removing the affected parts from service. The NPRM
also proposed to require inspecting the TR spline flange for corrosion,
impacts, fretting, wear, and a crack and depending on the inspection
results, removing the TR splined flange from service. For helicopters
with 9,000 or more total hours TIS or with unknown total hours TIS, the
NPRM proposed to require, within 15 hours TIS or 7 days, whichever
occurs first, and thereafter at intervals not to exceed 1,000 hours
TIS, removing from service any bolt, washer, and nut installed on the
TR hub body, replacing them with airworthy parts, inspecting the TR
splined flange, and depending on the inspection results, removing the
TR splined flange from service.

Additionally, the NPRM proposed to require, for helicopters with
less than 9,000 total hours TIS, within 1,000 hours TIS or before
accumulating 9,000 total hours TIS, whichever occurs first, and
thereafter at intervals not to exceed 1,000 hours TIS, removing from
service any bolt, washer, and nut installed on the TR hub body
replacing them with
airworthy parts, inspecting the TR splined flange, and depending on the
inspection results, removing the TR splined flange from service.
Finally, the NPRM proposed to prohibit the installation of a certain
part-numbered TR hub body unless certain actions have been
accomplished.

The NPRM was prompted by EASA AD 2021-0069, dated March 11, 2021
(EASA AD 2021-0069), 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, Model
EC120 B helicopters, all serial numbers. EASA advises that an
inspection of the TR hub body revealed a recurring loss of tightening
torque on several attachment bolts. This condition, if not addressed,
could result in cracking and potential loss of the TR drive and
consequent loss of yaw control of the helicopter.

Accordingly, EASA AD 2021-0069 retains the requirements of EASA AD
2019-0272R1, dated November 18, 2019 (EASA AD 2019-0272R1), which
prompted AD 2020-11-05, and requires additional repetitive detailed
inspections of the interface between the TR hub body part number
C642A0100103 and the splined flange. Depending on the inspection
results, EASA AD 2021-0069 requires accomplishment of applicable
corrective actions.

Discussion of Final Airworthiness Directive

Comments

The FAA received no comments on the NPRM or on the determination of
the costs.

Conclusion

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 reviewed the relevant
data, and determined that air safety requires adopting this AD as
proposed. Accordingly, the FAA is issuing this AD to address the unsafe
condition on these helicopters. Except for minor editorial changes,
this AD is adopted as proposed in the NPRM.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Airbus Helicopters Emergency Alert Service
Bulletin 05A020, Revision 2, dated February 8, 2021. This service
information specifies procedures for repetitive inspections of the TR
hub body for cracks and the TR spline flange for cracks and fretting
and the appropriate corrective actions.

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.

Differences Between This AD and EASA AD 2021-0069

EASA AD 2021-0069 uses flight hours (FH) for certain compliance
times, whereas this AD uses hours TIS. EASA AD 2021-0069 retains the
compliance time of November 1, 2019 for certain actions, which is the
effective date of EASA AD 2019-0272R1, whereas this AD requires
compliance in terms of the effective date of this AD.

Where Note 1 of EASA AD 2021-0069 allows a non-cumulative tolerance
of 100 FH to be applied to the compliance times for the initial
replacement of bolts, washers, and nuts (Table 1 of EASA AD 2021-0069)
to allow for synchronization of the required inspections with other
maintenance tasks, this AD does not allow a non-cumulative tolerance to
be applied to the compliance times.

Costs of Compliance

The FAA estimates that this AD affects 89 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 AD.

Visually inspecting each TR hub body for a crack takes about 0.25
work-hour for an estimated cost of $22 per inspection and $1,958 for
the U.S. fleet per inspection.

Visually inspecting each TR spline flange for corrosion, impacts,
fretting, wear, and a crack takes about 0.25 work-hour for an estimated
cost of $22 per inspection and $1,958 for the U.S. fleet per
inspection.

Replacing a TR hub body takes about 2 work-hours and parts would
cost about $16,417 for an estimated cost of $16,587 per TR hub body
replacement.

Replacing a TR spline flange takes about 0.5 work-hour and parts
would cost about $2,950 for an estimated cost of $2,993 per TR spline
flange replacement.

Replacing a bolt, washer, and nut takes about 0.5 work-hour and
parts would cost about $68 for an estimated cost of $111 per
replacement.

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.

Regulatory Findings

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 Order 12866,

(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
reference, Safety.

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:

a. Removing Airworthiness Directive 2020-11-05, Amendment 39-21130 (85
FR 31042, May 22, 2020); and

b. Adding the following new airworthiness directive: