DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0196; Project Identifier 2018-SW-021-AD]
RIN 2120-AA64

Airworthiness Directives; Airbus Helicopters Deutschland GmbH
Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

-----------------------------------------------------------------------

SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for Airbus Helicopters Deutschland GmbH Model MBB-BK 117 A-1, MBB-BK
117 A-3, MBB-BK 117 A-4, MBB-BK 117 B-1, MBB-BK 117 B-2, and MBB-BK 117
C-1 helicopters. This proposed AD was prompted by an analysis of the
main rotor (M/R) blade loop area. This proposed AD would require
repetitive inspections of certain M/R blade thimble areas and
corrective actions if necessary, as specified in a European Aviation
Safety Agency (now European Union Aviation Safety Agency) (EASA) AD,
which is proposed for incorporation by reference (IBR). The FAA is
proposing this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by May 10,
2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR
11.43 and 11.45, by any of the following methods:

Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the
instructions for submitting comments.

Fax: (202) 493-2251.

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

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

For material that is proposed for IBR in this AD, contact EASA,
Konrad-Adenauer-Ufer 3, 50668 Cologne, Germany; telephone +49 221 8999
000; email ADs@easa.europa.eu; internet www.easa.europa.eu. You may
find this material on the EASA website at https://ad.easa.europa.eu.
You may view this material 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 in the AD docket on the
internet at https://www.regulations.gov by searching for and locating
Docket No. FAA-2021-0196.

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-2021-0196;
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 NPRM, 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 FURTHER INFORMATION CONTACT: Kathleen Arrigotti, Aerospace
Engineer, Large Aircraft Section, International Validation Branch, FAA,
2200 South 216th St., Des Moines, WA; telephone (206) 231-3218; email
kathleen.arrigotti@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include "Docket No. FAA-2021-0196; Product Identifier
2018-SW-021-AD" at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
this proposal because of those comments.

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 post all comments received, without change, to
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this proposal.

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 Kathleen Arrigotti,
Aerospace Engineer, Large Aircraft Section, International Validation
Branch, FAA, 2200 South 216th St., Des Moines, WA; telephone (206) 231-
3218; email kathleen.arrigotti@faa.gov. Any commentary that the FAA
receives that is not specifically designated as CBI will be placed in
the public docket for this rulemaking.

Discussion

The EASA, which is the Technical Agent for the Member States of the
European, has issued EASA AD 2018-0061, dated March 20, 2018 (EASA AD
2018-0061), 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,
and MBB-BK117 C-1 helicopters, all serial numbers.

This proposed AD was prompted by new test results from an analysis
of the M/R blade loop area, which revealed that certain M/R blade
thimbles require reduced inspection intervals. The FAA is proposing
this AD to address composite failure of the M/R blades, resulting in
loss of control of the helicopter. See the EASA AD for additional
background information.

Related Service Information Under 1 CFR Part 51

EASA AD 2018-0061 specifies compliance intervals to repetitively
inspect certain M/R blades, with a blade sweep angle of 1 degree, for
cracks and resin chippings in the area of the greater thimble radius
and corrective actions, if there is a crack or anomaly. EASA AD 2018-
0061 also specifies compliance intervals to repetitively inspect
certain M/R blades, with a blade sweep angle of 0 degrees, for cracks
and bulging in the teflon foil in the area of the greater thimble
radius and corrective actions, if there is a crack or bulge. Corrective
actions include dispatching the M/R blades to an authorized repair
station, as required.

This material 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.

FAA's Determination and Requirements of This Proposed AD

These products have been approved by the aviation authority of
another country, and are approved for operation in the United States.
Pursuant to the bilateral agreement with the State of Design Authority,
the FAA has been notified of the unsafe condition described in the EASA
AD referenced above. The FAA is proposing this AD after evaluating all
the relevant information and determining the unsafe condition described
previously is likely to exist or develop in other products of the same
type designs.

Proposed AD Requirements

This proposed AD would require accomplishing the actions specified
in EASA AD 2018-0061 described previously, as incorporated by
reference, except for any differences identified as exceptions in the
regulatory text of this proposed AD and except as discussed under
"Differences Between this Proposed AD and the EASA AD."

Explanation of Required Compliance Information

In the FAA's ongoing efforts to improve the efficiency of the AD
process, the FAA initially worked with Airbus and EASA to develop a
process to use certain EASA ADs as the primary source of information
for compliance with requirements for corresponding FAA ADs. The FAA has
since coordinated with other manufacturers and civil aviation
authorities (CAAs) to use this process. As a result, EASA AD 2018-0061
will be incorporated by reference in the FAA final rule. This proposed
AD would, therefore, require compliance with EASA AD 2018-0061 in its
entirety, through that incorporation, except for any differences
identified as exceptions in the regulatory text of this proposed AD.
Using common terms that are the same as the heading of a particular
section in the EASA AD does not mean that operators need comply only
with that section. For example, where the AD requirement refers to
"all required actions and compliance times," compliance with this AD
requirement is not limited to the section titled "Required Action(s)
and Compliance Time(s)" in the EASA AD. Service information specified
in EASA AD 2018-0061 that is required for compliance with EASA AD 2018-
0061 will be available on the internet at https://www.regulations.gov
by searching for and locating Docket No. FAA-2021-0196 after the FAA
final rule is published.

Differences Between This Proposed AD and the EASA AD

The EASA AD applies to 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,
whereas this proposed AD would apply to Model MBB-BK 117 A-1, MBB-BK
117 A-3, MBB-BK 117 A-4, MBB-BK 117 B-1, MBB-BK 117 B-2, and MBB-BK 117
C-1 helicopters with certain M/R blades installed instead. The service
information required by the EASA AD requires accomplishment of certain
corrective action by "ECD" or an authorized service or repair
station, whereas this proposed AD would require performing the
corrective action in accordance with FAA-approved procedures, instead.
The EASA AD requires revising the Aircraft Maintenance Program (AMP),
whereas this proposed AD would not. The EASA AD allows a tolerance to
compliance times, whereas this proposed AD would not.

Costs of Compliance

The FAA estimates that this proposed AD affects 216 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 proposed AD.

Inspecting an M/R blade thimble area would take about 1 work-hour
for an estimated cost of about $85 per M/R blade thimble, per
inspection cycle.

Repairing or replacing an M/R blade could take up to about 20 work-
hour(s) and parts could cost up to about $23,100 for an estimated cost
of up to $24,800 per blade.

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 above, 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 adding the following new airworthiness
directive: