DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2017-1123; Product Identifier 2017-SW-013-AD; Amendment
39-21176; AD 2020-15-13]
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) 2017-02-07
for Airbus Helicopters Deutschland GmbH (Airbus Helicopters) Model MBB-
BK 117 C-2 and Model MBB-BK 117 D-2 helicopters. AD 2017-02-07 required
a repetitive inspection and a one-time torque of each hydraulic module
plate assembly attachment point (attachment point). This new AD retains
the initial inspection and torque requirements of AD 2017-02-07 and
requires replacing the attachment point hardware. This AD was prompted
by a terminating action has been developed to address the unsafe
condition. The actions of this AD are intended to address an unsafe
condition on these products.

DATES: This AD is effective August 31, 2020.

The Director of the Federal Register approved the incorporation by
reference of certain publications listed in this AD as of August 31, 2020.

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-2017-1123.

Examining the AD Docket

You may examine the AD docket on the internet at https://www.regulations.gov
in Docket No. FAA-2017-1123; 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: Matt Fuller, AD Program Manager,
Continued Operational Safety Branch, Airworthiness Products Section,
General Aviation and Rotorcraft Unit, FAA, 10101 Hillwood Pkwy., Fort
Worth, TX 76177; telephone 817-222-5110; email matthew.fuller@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

The FAA issued a supplemental notice of proposed rulemaking (SNPRM)
to amend 14 CFR part 39 to supersede AD 2017-02-07, Amendment 39-18786
(82 FR 10267, February 10, 2017) ("AD 2017-02-07"). AD 2017-02-07
applied to Airbus Helicopters Model MBB-BK 117 C-2 helicopters, serial
numbers up to and including 9750, and Model MBB-BK 117 D-2 helicopters,
serial numbers up to and including 20110, with a hydraulic module plate
assembly part number B291M0003103 with a single locking attachment
point installed. The SNPRM published in the Federal Register on
February 27, 2020 (85 FR 11315). The FAA preceded the SNPRM with a
notice of proposed rulemaking (NPRM) that published in the Federal
Register on December 5, 2017 (82 FR 57390). The NPRM proposed to retain
the initial inspection and torque requirements of AD 2017-
02-07 and require replacing each single locking attachment point
mechanism with a double locking attachment point mechanism. The SNPRM
proposed to add a requirement to reposition the aft grounding straps
and inspect the clamping effect of the aft attachment points when the
double locking attachment hardware is installed, and for helicopters
that have previously installed the double locking attachment hardware,
the SNPRM proposed to add an alternative clamp effect inspection
requirement. The SNPRM also corrected the torque application
requirement proposed in the NPRM to just each forward (not aft)
attachment point.

The NPRM was prompted by EASA AD No. 2017-0047, dated March 13,
2017, issued by EASA, which is the Technical Agent for the Member
States of the European Union, to correct an unsafe condition on Airbus
Helicopters Deutschland GmbH (formerly Eurocopter Deutschland GmbH)
Model MBB-BK117 C-2, MBB-BK117 C-2e, MBB-BK117 D-2 and MBB-BK117 D-2m
helicopters. EASA advises that the hydraulic plate assembly on certain
MBB-BK117 models has four attachment points on the fuselage secured by
a single locking mechanism. According to EASA, a design reassessment
revealed stiffness of the hydraulic plate may be insufficient to
withstand the in-service loads in the event one of the four single
locking attachment points fails. The EASA AD requires a repetitive
inspection and one-time torque tightening of the attachment points
until replacement of the single locking attachment hardware with double
locking attachment hardware.

Comments

The FAA gave the public the opportunity to participate in
developing this final rule. The FAA has considered the comment
received. One commenter commented in support of the SNPRM.

FAA's Determination

The FAA has reviewed the relevant information and determined that
an 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 specifies performing the visual inspection of each
attachment point at intervals not exceeding 400 flight hours. This AD
does not require a repetitive inspection. This AD requires the
replacement of each single locking attachment point mechanism with a
double locking attachment point mechanism within 300 hours TIS instead,
which makes subsequent inspections unnecessary. Since EASA has not
revised or superseded its AD to incorporate Revision 3 of the service
information, the EASA AD does not require inspecting the clamping
effect of the aft joints, torque tightening the bolts, and corrective
action if necessary for helicopters with a hydraulic module plate
assembly with double locking attachment hardware installed in
accordance with Airbus Helicopters Alert Service Bulletin (ASB) No. ASB
MBB-BK117 C-2-29A-003 or ASB No. ASB MBB-BK117 D-2-29A-001, both
Revision 2 and dated February 1, 2017.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Airbus Helicopters ASB No. ASB MBB-BK117 C-2-29A-
003 for Model MBB-BK 117 C-2 helicopters and ASB No. ASB MBB-BK117 D-2-
29A-001 for Model MBB-BK 117 D-2 helicopters, both Revision 3 and dated
December 19, 2017. Until the attachment points are modified with double
locking attachment mechanisms, this service information specifies a
repetitive visual inspection for condition and correct installation of
the attachment points and replacing the affected parts if there is a
crack. This service information also specifies a tightening torque
check of the forward attachment points after the initial inspection and
replacing the affected parts if torque cannot be applied. This service
information specifies procedures to replace the single locking
attachment hardware with double locking attachment hardware.

For certain helicopters with a hydraulic module plate assembly with
the double locking attachment hardware installed, this revision of the
service information contains procedures to inspect the clamping effect
of the aft attachment points and torque tightening the screw joints
(bolts). If a bolt can be turned while applying this torque, the
service information specifies instructions to replace the split pin,
washer, and self-locking castellated nut, check the bolt for wear and
replace it if necessary, change the position of the aft grounding
strap, check the electrical bonding, and apply PU-Lacquer to the
grounding connection.

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 also reviewed Airbus Helicopters ASB No. ASB MBB-BK117 C-2-
29A-003 for Model MBB-BK 117 C-2 helicopters and ASB No. ASB MBB-BK117
D-2-29A-001 for Model MBB-BK 117 D-2 helicopters, both Revision 1 and
dated October 14, 2016, and both Revision 2 and dated February 1, 2017.
Revisions 1 and 2 of this service information contain the same visual
inspection and torque tightening check procedures as Revision 3.
Revision 2 of this service information adds the procedures to replace
the single locking attachment hardware with double locking attachment
hardware and contains the same forward locking attachment hardware
replacement procedures as Revision 3.

Costs of Compliance

The FAA estimates that this AD affects 167 helicopters of U.S.
Registry. The FAA estimates that operators may incur the following
costs in order to comply with this AD. The FAA estimates the cost of
labor at $85 per work-hour.

Visually inspecting the four attachment points takes about 0.75
work-hour for an estimated cost of $64 per helicopter and $10,688 for
the U.S. fleet. Inspecting the torque of the attachment points takes
about 0.25 work-hour for an estimated cost of $21 per helicopter and
$3,507 for the U.S. fleet. Replacing any of the attachment point parts
takes a minimal amount of time and parts cost about $48 per attachment
point. Installing four double locking attachment point mechanisms takes
a minimal amount of time and parts cost about $400 per helicopter and
$66,800 for the U.S. fleet.

For certain double locking attachment hardware aft joints,
inspecting the clamping effect and applying torque takes about 1 work-
hour for an estimated cost of $85 per helicopter. If required,
inspecting and replacing parts, repositioning the aft grounding strap,
inspecting the electrical bonding, and applying lacquer to the
grounding connection takes about 0.5 work-hour and parts cost about $15
for an estimated cost of $58 per helicopter.

According to Airbus Helicopters' service information, some of the
costs of this AD may be covered under warranty, thereby reducing the
cost impact on affected individuals. The FAA does not control warranty
coverage by Airbus Helicopters. Accordingly, the FAA has included all
costs in this cost estimate.

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 removing Airworthiness Directive (AD)
2017-02-07, Amendment 39-18786 (82 FR 10267, February 10, 2017), and
adding the following new AD: