DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0801; Product Identifier 2019-SW-101-AD; Amendment
39-21472; AD 2021-06-05]
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 superseding Airworthiness Directive (AD) 2017-07-08
for Airbus Helicopters Deutschland GmbH (Airbus Helicopters) Model MBB-
BK 117 D-2 helicopters. AD 2017-07-08 required repetitively inspecting
each engine mount elastomeric bushing (elastomeric bushing). Since the
FAA issued AD 2017-07-08, Airbus Helicopters has designed an improved
engine mount metal bushing (metal bushing). This new AD retains the
inspection requirements of AD 2017-07-08 and requires replacing each
affected engine mount bushing with an improved engine mount bushing,
while also requiring repetitive inspections of the improved engine
mount bushing. This AD also prohibits installing an elastomeric bushing
on any helicopter. The actions of this AD are intended to address an
unsafe condition on these products.

DATES: This AD is effective May 7, 2021.

The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of May 7, 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 this 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-2020-0801.

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.gov
in Docket No. FAA-2020-0801; 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: Matt Fuller, AD Program Manager,
General Aviation & Rotorcraft Unit, Airworthiness Products Section,
Operational Safety Branch, FAA, 10101 Hillwood Pkwy., Fort Worth, TX
76177; telephone (817) 222-5110; email matthew.fuller@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to remove AD 2017-07-08, Amendment 39-18846 (82 FR 16895,
April 7, 2017) (AD 2017-07-08), and add a new AD. AD 2017-07-08 applied
to Airbus Helicopters Model MBB-BK 117 D-2 helicopters and required
repetitive visual inspections of each elastomeric bushing of the inner
and outer forward trusses of both engines, and depending on the outcome
of the inspections, repairing or replacing the elastomeric bushings. AD
2017-07-08 was prompted by EASA AD 2015-0198, dated September 30, 2015
(EASA AD 2015-0198), issued by EASA, which is the Technical Agent for
the Member States of the European Union. EASA advised that during a
pre-flight check of a Model MBB-BK 117 D-2 helicopter, an elastomeric
bushing was found delaminated. More cases of delaminated elastomeric
bushings were reported following additional investigations. According
to EASA, this condition could lead to cracks and eventually failure of
the engine mount front support pins, possibly resulting in loss of
helicopter control.

The NPRM published in the Federal Register on August 27, 2020 (85
FR 52931) and was prompted by EASA issuing a series of ADs to supersede
EASA AD 2015-0198. EASA issued AD 2019-0030, dated February 13, 2019
(EASA AD 2019-0030), to supersede EASA AD 2015-0198. EASA AD 2019-0030
advises that Airbus Helicopters has designed an improved engine mount
bushing P/N B712M10X1001, which when installed becomes a terminating
action for the repetitive inspections of elastomeric bushing P/N 105-
60386. Accordingly, EASA AD 2019-0030 requires installation of improved
engine mount bushing P/N B712M10X1001 and also prohibits the
installation of elastomeric bushing P/N 105-60386 on any Model MBB-BK
117 D-2 helicopter. Since EASA issued AD 2019-0030, occurrences were
reported of finding damaged metal bushings. EASA issued AD 2019-0275,
dated November 7, 2019 (EASA AD 2019-0275), which retains the
requirements of EASA AD 2019-0030 and requires repetitive visual
inspections of the metal bushings. EASA AD 2019-0275 also updates the
terminology used in the definitions section from affected part to
elastomeric bushing and from serviceable part to metal bushing. The
NPRM proposed to retain the repetitive visual inspections of AD 2017-
07-08 and proposed to require installing metal bushing part number (P/
N) B712M10X1001, which would terminate the repetitive inspections of
elastomeric bushing P/N 105-60386. The NPRM also proposed to require
repetitive inspections of metal bushing P/N B712M10X1001 and prohibit
the installation of elastomeric bushing P/N 105-60386 on any
helicopter.

Comments

The FAA gave the public the opportunity to participate in
developing this final rule, but the FAA did not receive any comments on
the NPRM or on the determination of the cost to the public.

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 design and that air safety and the
public interest require adopting the AD requirements as proposed.

Differences Between This AD and the EASA AD

EASA AD 2019-0275 allows a non-cumulative tolerance of 10 hours
time-in-service for its required compliance times. This AD does not.
EASA AD 2019-0275 requires reporting inspection results to Airbus
Helicopters Deutschland GmbH if any worn or heavily worn metal is
found, whereas this AD does not.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Airbus Helicopters Alert Service Bulletin (ASB)
MBB-BK117 D-2-71A-002, Revision 1, dated December 14, 2018. This
service information specifies instructions for repetitive visual
inspections of elastomeric bushing P/N 105-60386 for defects,
deformation, separation of the rubber, and missing rubber. If there is
any deformation or separation of the rubber, this service information
provides instructions to replace the affected parts with serviceable
parts. This service information also specifies replacing elastomeric
bushings P/N 105-60386 with metal bushings P/N B712M10X1001. This
service information also does not allow the new metal bushings P/N
B712M10X1001 to be installed on any helicopter together with the
elastomeric bushings P/N 105-60386. This service information also
prohibits installing elastomeric bushings P/N 105-60386 after
installation of new metal bushings P/N B712M10X1001.

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.

Other Related Service Information

The FAA reviewed Airbus Helicopters ASB MBB-BK117 D-2-71A-011,
Revision 0, dated October 16, 2019. This service information specifies
instructions for repetitive inspections of
the metal bushings P/N B712M10X1001 of the inner and outer forward
trusses for worn metal bushings (gapping between the inner and outer
truss less than 1mm) and heavily worn metal bushings (inner and outer
metal bushings showing contact marks or worn out metal mesh).

The FAA also reviewed Airbus Helicopters AMM BK117 C2C2e, dated
August 7, 2018. This service information specifies instructions for a
detailed inspection of the engine mount bushings.

Costs of Compliance

The FAA estimates that this AD affects 30 helicopters of U.S.
Registry. The FAA estimates that operators may incur the following
costs in order to comply with this AD. Labor costs are estimated at $85
per work-hour.

Inspecting the engine mount bushings will take about 1 work-hour,
for an estimated cost of $85 per helicopter and $2,550 for the U.S.
fleet. Replacing the three engine mount bushings will take about 8
work-hours and parts would cost about $2,505, for an estimated cost of
$3,185 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 products identified in this rulemaking action.

Regulatory Findings

The FAA has determined that 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:

a. Removing Airworthiness Directive (AD) 2017-07-08, Amendment 39-18846
(82 FR 16895, April 7, 2017); and

b. Adding the following new AD: