DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0967; Product Identifier 2018-SW-013-AD; Amendment
39-21394; AD 2021-02-11]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters Deutschland GmbH
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for
Airbus Helicopters Deutschland GmbH Model MBB-BK117 A-1, MBB-BK117 A-3,
MBB-BK117 A-4, MBB-BK117 B-1, MBB-BK117 B-2, MBB-BK117 C-1, and MBB-
BK117 C-2 helicopters. This AD requires inspecting the tail gearbox
(TGB) bellcrank attachment arm (arm) for a crack. This AD was prompted
by a report of a cracked TGB arm. The actions of this AD are intended
to address an unsafe condition on these products.

DATES: This AD is effective April 15, 2021.
The Director of the Federal Register approved the incorporation by
reference of certain documents listed in this AD as of April 15, 2021.

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
https://www.airbus.com/helicopters/services/technical-support.html. You
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-2020-0967.

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-
0967; 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 Aviation Safety Agency (now 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: Kristi Bradley, Aviation Safety
Engineer, General Aviation & Rotorcraft Section, International
Validation Branch, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177;
telephone (817) 222-5110; email kristin.bradley@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

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
Deutschland GmbH Model MBB-BK117 A-1, MBB-BK117 A-3, MBB-BK117 A-4,
MBB-BK117 B-1, MBB-BK117 B-2, MBB-BK117 C-1, and MBB-BK117 C-2
helicopters. The NPRM published in the Federal Register on October 26,
2020 (85 FR 67694). The NPRM proposed to require dye-penetrant
inspecting the TGB arm for a crack and for any dent, nick, and scratch,
and depending on the inspection results, replacing the TGB, removing
the surface material up to 0.2 mm using 80-grit abrasive paper and
repeating the dye penetrant inspection, or finishing the surface with
600-grit or finer abrasive paper. The proposed requirements were
intended to detect a crack in the TGB arm.
The NPRM was prompted by EASA AD No. 2018-0046, dated February 19,
2018, issued by EASA, which is the Technical Agent for the Member
States of the European Union, to correct an unsafe condition for Airbus
Helicopters Deutschland GmbH (AHD) (formerly Eurocopter Deutschland
GmbH, Eurocopter Hubschrauber GmbH, Messerschmitt-B[ouml]lkow-Blohm
GmbH), Airbus Helicopters Inc. (formerly American Eurocopter LLC) Model
MBB-BK117 A-1, MBB-BK117 A-3, MBB-BK117 A-4, MBB-BK117 B-1, MBB-BK117
B-2, MBB-BK117 C-1, and MBB-BK117 C-2 helicopters. EASA advises that a
crack was detected on a Model MBB-BK117 A-4 TGB arm and that this
condition, if not corrected, could result in disconnection of the arm
from the TGB and possible loss of control of the helicopter. To address
this unsafe condition, the EASA AD requires an inspection of the TGB
arm for a crack and for surface anomalies.

Comments

The FAA gave the public the opportunity to participate in
developing this final rule. The FAA received comments from two
commenters in support of the NPRM.

FAA's Determination

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 these same type designs and that air safety and the
public interest require adopting the AD requirements as proposed.

Differences Between This AD and the EASA AD

The EASA AD requires operators to contact Airbus Helicopters if
there is a crack or if there is damage that cannot be repaired by
removing surface material, whereas this AD requires replacing the TGB
instead.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Airbus Helicopters Alert Service Bulletin (ASB)
MBB-BK117 C-2-65A-008 for Model MBB-BK117 C-2 helicopters and ASB MBB-
BK117-30A-120 for Model MBB-BK117 A-1, MBB-BK117 A-3, MBB-BK117 A-4,
MBB-BK117 B-1, MBB-BK117 B-2, and MBB-BK117 C-1 helicopters, each
Revision 0 and dated January 31, 2018. The service information contains
procedures for inspecting the TGB arm for a crack and surface
anomalies.
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 177 helicopters of U.S.
Registry. Labor rates are estimated at $85 per work-hour. Based on
these numbers, the FAA estimates that operators may incur the following
costs in order to comply with this AD.
Removing the surface coating and inspecting the TGB arm for a crack
takes about 2 work-hours and the cost of materials is minimal, for an
estimated cost of $170 per helicopter and $30,090 for the U.S. fleet.
If required, reworking the TGB arm takes about 1 work-hour and the
cost of materials is minimal, for an estimated cost of $85 per
helicopter. Replacing a TGB with a cracked arm takes about 4.5 work-
hours and costs about $69,000 for required parts, for an estimated cost
of $69,383 per helicopter.

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.

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.

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
directive: