DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0450; Project Identifier 2017-SW-100-AD; Amendment
39-21680; AD 2021-16-17]
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-BK 117 D-2
helicopters. This AD was prompted by the discovery that certain parts
that are approved for installation on multiple helicopter models are
life limited parts when installed on Model MBB-BK 117 D-2 helicopters
and some helicopter delivery documents excluded the life limit
information. This AD requires determining the total hours time-in-
service (TIS) of a certain part-numbered rotor mast nut and re-
identifying a certain part-numbered rotor mast nut. This AD also
requires establishing a life limit for a certain part-numbered rotor
mast nut and helical gear support, and removing each part from service
before reaching its life limit. Additionally, this AD requires
replacing a certain part-numbered main gearbox (MGB) with a not
affected MGB as specified in a European Aviation Safety Agency (now
European Union Aviation Safety Agency) (EASA) AD, which is incorporated
by reference (IBR). The FAA is issuing this AD to address the unsafe
condition on these products.
DATES: This AD is effective October 13, 2021.
The Director of the Federal Register approved the incorporation by
reference of a certain publication listed in this AD as of October 13,
ADDRESSES: For EASA material incorporated by reference (IBR) in
AD, 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 the referenced service
information 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 at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0450.
Examining the AD Docket
You may examine the AD docket at https://www.regulations.gov by
searching for and locating Docket No. FAA-2021-0450; 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 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: Rao Edupuganti, Aerospace Engineer,
Dynamic Systems Section, Technical Innovation Policy Branch, Policy &
Innovation Division, FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177;
telephone (817) 222-5110; email email@example.com.
EASA AD 2017-0037, dated February 22, 2017 (EASA AD 2017-0037),
issued by EASA, which is the Technical Agent for the Member States of
the European Union, to correct an unsafe condition for Airbus
Helicopters Deutschland GmbH (formerly Eurocopter Deutschland GmbH),
Airbus Helicopters Inc. (formerly American Eurocopter LLC) Model MBB-BK
117 D-2 and MBB-BK117 D-2m helicopters.
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 by adding an AD that would apply to Airbus Helicopters
Deutschland GmbH (AHD) Model MBB-BK 117 D-2 helicopters, with an
affected MGB or affected rotor mast nut as identified in Note 1 of EASA
AD 2017-0037. The NPRM published in the Federal Register on June 7,
2021 (86 FR 30218). The NPRM was prompted by the discovery that certain
parts that are approved for installation on multiple helicopter models
are life limited parts when installed on Model MBB-BK 117 D-2
helicopters and some helicopter delivery documents excluded the life
limit information, The NPRM proposed to require accomplishing the
actions specified in EASA AD 2017-0037, described previously, as
incorporated by reference, except for any differences identified as
exceptions in the regulatory text of this AD and except as discussed
under ``Differences Between this AD and EASA AD 2017-0037.'' The FAA is
issuing this AD to address an unsafe condition on these products. See
EASA AD 2017-0037 for additional background information.
Discussion of Final Airworthiness Directive
The FAA received no comments on the NPRM or on the determination of
These helicopters 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 reviewed the relevant
data and determined that air safety requires adopting this AD as
proposed. Accordingly, the FAA is issuing this AD to address the unsafe
condition on these products.
Related Service Information Under 1 CFR Part 51
EASA AD 2017-0037 requires establishing a life limit for rotor mast
nut part number (P/N) D632K1133-201 and helical gear support P/N
D632K1113-201, and replacing these parts before exceeding their life
limit. EASA AD 2017-0037 also requires replacing each rotor mast nut P/
N D632K1133-201 for which the hours TIS are unknown and replacing
certain part-numbered rotor mast nuts before accumulating 3,708 hours
TIS since first installation on a helicopter. EASA AD 2017-0037
requires re-identifying each rotor mast nut P/N 117-12133-01 to P/N
D632K1133-201 by following the specified service information. EASA AD
2017-0037 requires replacing any MGB P/N D632K1001-051 with serial
number (S/N) D2-0001 up to D2-0108 inclusive, D2-0123, D2-0126, D2-0127,
D2-0130 up to D2-0136 inclusive with a not affected MGB before the
affected MGB accumulates 3,708 hours TIS. EASA AD 2017-0037 also
prohibits installing an affected rotor mast nut or an affected MGB that
has accumulated more than 3,708 hours TIS since first installation on
helicopter. Additionally, EASA AD 2017-0037 requires revising the
Aircraft Maintenance Program (AMP).
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 Alert Service Bulletin MBB-
BK117 D-2-63A-001, Revision 0, dated December 1, 2016 (ASB 63A-001),
which is not incorporated by reference, which specifies procedures for
re-identifying the rotor mast nut by using a vibrograph, crossing out
the old P/N and marking the new P/N on the outer surface, engraving the
letter ``A'' behind the S/N of each part, and updating the historical
record and log card to confirm compliance with ASB 63A-001. ASB 63A-001
also specifies during the next MGB overhaul, making an entry in the log
card to confirm re-identification of the helical gear support, and
annotating the S/N of the helical gear support.
Differences Between This AD and EASA AD 2017-0037
EASA AD 2017-0037 applies to Model MBB-BK117 D-2 and D2m
helicopters, whereas this AD only applies to Model MBB-BK117 D-2
helicopters because Model D-2m is not FAA type-certificated. If the
total hours TIS for an affected rotor mast nut cannot be determined,
this AD requires removing the rotor mast nut from service before
further flight, whereas EASA AD 2017-0037 does not contain this
requirement. EASA AD 2017-0037 requires using a vibrograph to re-
identify certain rotor mast nuts, whereas this AD requires using a
vibro etch instead. EASA AD 2017-0037 requires replacing certain parts,
whereas this AD requires removing certain parts from service instead.
EASA AD 2017-0037 requires revising the AMP, whereas this AD does not.
Costs of Compliance
The FAA estimates that this AD affects 30 helicopters of U.S.
Registry. Labor rates are estimated at $85 per work-hour. Based on
these numbers, the FAA estimates the following costs to comply with
Determining the total hours TIS on an affected rotor mast nut takes
about 1 work-hour for an estimated cost of $85 per helicopter and
$2,550 for the U.S. fleet.
Re-identifying a rotor mast nut takes about 1.5 work-hours for an
estimated cost of $128 per rotor mast nut.
Replacing a rotor mast nut takes about 6 work-hours and parts cost
about $5,351 for an estimated cost of $5,861 per rotor mast nut.
Replacing a MGB, which includes replacing the helical gear support,
takes about 42 work-hours and parts cost about $295,000 (overhauled)
for an estimated cost of $298,570.
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 helicopters 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