DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0801; Product Identifier 2019-SW-101-AD]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters Deutschland GmbH
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede Airworthiness Directive (AD)
2017-07-08 for Airbus Helicopters Deutschland GmbH (Airbus Helicopters)
Model MBB-BK 117 D-2 helicopters. AD 2017-07-08 requires 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 proposed AD
would retain the inspection requirements of AD 2017-07-08 and would
require replacing each affected engine mount bushing with an improved
engine mount bushing, while also requiring repetitive inspections of
the improved engine mount bushing. This proposed AD would also prohibit
installing an elastomeric bushing on any helicopter. The actions of
this proposed AD are intended to address an unsafe condition on these
products.

DATES: The FAA must receive comments on this proposed AD by October 13,
2020.

ADDRESSES: You may send comments by any of the following methods:

Federal eRulemaking Docket: Go to https://www.regulations.gov. Follow the
online instructions for sending your comments electronically.

Fax: 202-493-2251.

Mail: Send comments to the U.S. Department of Transportation, Docket
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New
Jersey Avenue SE, Washington, DC 20590-0001.

Hand Delivery: Deliver to the "Mail" address between 9 a.m. and 5 p.m.,
Monday through Friday, except Federal holidays.

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-2020-0801;
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 proposed AD, the European Union Aviation Safety Agency (EASA) AD,
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 service information identified in this proposed 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.

FOR FURTHER INFORMATION CONTACT: Matt Fuller, AD Program Manager,
Continued Operational Safety Branch, Airworthiness Products Section,
General Aviation and Rotorcraft Unit, 10101 Hillwood Pkwy., Fort Worth,
TX 76177; telephone 817-222-5110; email Matthew.Fuller@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to participate in this rulemaking by submitting
written comments, data, or views. 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 send only one
copy of written comments, or if comments are filed electronically,
commenters should submit only one time.

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 file in the docket all comments received, 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 on or before 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 proposal in light
of the comments received.

Confidential Business Information

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 Matt Fuller, AD Program Manager, Continued
Operational Safety Branch, Airworthiness Products Section, General
Aviation and Rotorcraft Unit, 10101 Hillwood Pkwy., Fort Worth, TX
76177; telephone 817-222-5110; email Matthew.Fuller@faa.gov. Any
commentary that the FAA receives which is not specifically designated
as CBI will be placed in the public docket for this rulemaking.

Discussion

The FAA issued AD 2017-07-08, Amendment 39-18846 (82 FR 16895,
April 7, 2017) ("AD 2017-07-08") for Airbus Helicopters Model MBB-BK
117 D-2 helicopters. AD 2017-07-08 requires 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 No. 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.

Actions Since AD 2017-07-08 Was Issued

Since the FAA issued AD 2017-07-08, EASA has issued a series of ADs
to supersede EASA AD 2015-0198. EASA issued AD No. 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 part number (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 No. 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.

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 about the
unsafe condition described in its AD. The FAA is proposing this AD
after evaluating all known relevant information and determining that an
unsafe condition is likely to exist or develop on other helicopters of
the same type design.

Differences Between This Proposed AD and the EASA AD

The EASA AD allows a non-cumulative tolerance of 10 hours time-in-
service for its required compliance times. This proposed AD does not.
The EASA AD requires reporting inspection results to Airbus Helicopters
Deutschland GmbH if any worn or heavily worn metal is found, whereas
this proposed 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 1 mm) 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.

Proposed AD Requirements

This proposed AD would retain the repetitive visual inspections of
AD 2017-07-08 and would propose requiring the installation of metal
bushing P/N B712M10X1001, which would terminate the repetitive
inspection of elastomeric bushing P/N 105-60386. This proposed AD would
also require repetitive inspections of metal bushing P/N B712M10X1001
and prohibit the installation of elastomeric bushing P/N 105-60386 on
any helicopter.

Costs of Compliance

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

Inspecting the engine mount bushings would 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 would 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 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, I certify this proposed regulation:

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 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:

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

b. Adding the following new AD: