DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0265; Project Identifier MCAI-2020-01541-R;
Amendment 39-21603; AD 2021-12-16]
Airworthiness Directives; Airbus Helicopters Deutschland GmbH
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD)
Airbus Helicopters Deutschland GmbH (AHD) Model MBB-BK117 C-2 and MBB-
BK117 D-2 helicopters. This AD was prompted by a report of increased
control force in the collective axis. This AD requires repetitive
visual inspections of the main rotor actuator (MRA), as specified in a
European Union Aviation Safety Agency (EASA) AD, which is incorporated
by reference. The FAA is issuing this AD to address the unsafe
condition on these products.
DATES: This AD is effective August 3, 2021.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of August 3,
ADDRESSES: For material incorporated by reference (IBR) in this
contact the 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-2021-0265.
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-
0265; 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 final rule, any comments received, and other information. The
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: Katherine Venegas, Aviation Safety
Engineer, Los Angeles ACO Branch, FAA, 3960 Paramount Blvd., Lakewood,
California 90712; telephone (562) 627-5353; email
The EASA, which is the Technical Agent for the Member States of the
European Union, has issued EASA AD 2018-0283, dated December 20, 2018
(EASA AD 2018-0283), to correct an unsafe condition for AHD Model MBB-
BK117 C-2 and MBB-BK117 D-2 helicopters. EASA later issued EASA AD
2020-0257, dated November 17,
2020 (EASA AD 2020-0257), to supersede EASA AD 2018-0283.
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to AHD Model MBB-BK117 C-2
and MBB-BK117 D-2 helicopters. The NPRM published in the Federal
Register on April 8, 2021 (86 FR 18221). The NPRM was prompted by a
report of increased control force in the collective axis on an AHD
Model EC135 helicopter. Subsequent inspections determined that a nut on
a piston of the MRA had cracked and separated from the piston rod. Due
to design similarity, Model MBB-BK117 C-2 and MBB-BK117 D-2 helicopters
are also affected by this unsafe condition. The NPRM proposed to
require repetitive visual inspections of the MRA as specified in EASA
The FAA is issuing this AD to prevent failure of the MRA and
subsequent loss of control of the helicopter. See the EASA AD for
additional background information.
Discussion of Final Airworthiness Directive
The FAA gave the public the opportunity to participate in
developing this final rule. The FAA received no comments on the NPRM or
on the determination of the cost to the public.
The FAA reviewed the relevant data and determined that air safety
and the public interest require adopting this final rule as proposed,
except the compliance time for the reporting requirement has changed
from within 30 days after the effective date of this AD to within 30
days after accomplishing each inspection and determining that there is
a crack, damage, black coloration, or corrosion. The FAA has determined
that this change:
Is consistent with the intent that was proposed in the
NPRM for addressing the unsafe condition; and
Does not add any additional burden upon the public than
was already proposed in the NPRM.
The FAA also determined that this change will not increase the
economic burden on any operator or increase the scope of this final
Related Service Information Under 1 CFR Part 51
EASA AD 2020-0257 specifies procedures for a repetitive visual
inspection of the MRA and depending on the results, replacing the
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.
Differences Between This AD and the EASA AD
The EASA AD requires contacting Airbus Helicopters or replacing an
affected part, whereas this AD requires performing the corrective
action in accordance with FAA-approved procedures or removing the
affected parts from service instead. The service information referenced
in the EASA AD refers to calendar time when specifying the compliance
time for the inspections, whereas this AD uses hours time-in-service.
The EASA AD allows a tolerance to the compliance times, whereas this AD
does not. The EASA AD does not specify a compliance time for the
reporting requirements; whereas this AD requires performing the
reporting action within 30 days after accomplishing each inspection and
determining that there is a crack, damage, black coloration, or
The FAA considers this AD interim action. If final action is later
identified, the FAA might consider further rulemaking then.
Costs of Compliance
The FAA estimates that this 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 AD.
Inspecting the nuts on the MRA pistons takes about 1 work-hour for
an estimated cost of $85 per helicopter and $18,360 for the U.S. fleet,
per inspection cycle.
Replacing the MRA takes about 7 work-hours and parts cost about
$286,554 for an estimated cost of $287,149 per helicopter.
Repairing the MRA takes up to about 8 work-hours and parts cost
about $110 for an estimated cost of up to $790 per MRA.
If required, reporting information takes about 1 work-hour for an
estimated cost of $85 per instance.
Paperwork Reduction Act
A federal agency may not conduct or sponsor, and a person is not
required to respond to, nor shall a person be subject to penalty for
failure to comply with a collection of information subject to the
requirements of the Paperwork Reduction Act unless that collection of
information displays a current valid OMB control number. The control
number for the collection of information required by this AD is 2120-
0056. The paperwork cost associated with this AD has been detailed in
the Costs of Compliance section of this document and includes time for
reviewing instructions, as well as completing and reviewing the
collection of information. Therefore, all reporting associated with
this AD is mandatory. Comments concerning the accuracy of this burden
and suggestions for reducing the burden should be directed to
Information Collection Clearance Officer, Federal Aviation
Administration, 10101 Hillwood Pkwy., Fort Worth, TX 76177-1524.
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.
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
(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
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