DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2017-1123; Product Identifier 2017-SW-013-AD]
Airworthiness Directives; Airbus Helicopters Deutschland GmbH
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Supplemental notice of proposed rulemaking (SNPRM); reopening
of comment period.
SUMMARY: The FAA is revising an earlier proposal for Airbus Helicopters
Deutschland GmbH (Airbus Helicopters) Model MBB-BK 117 C-2 and Model
MBB-BK 117 D-2 helicopters. This action revises the notice of proposed
rulemaking (NPRM) by changing one of the required actions. The FAA is
proposing this airworthiness directive (AD) to address the unsafe
condition on these products. Since these actions impose an additional
burden over that proposed in the NPRM, the FAA is reopening the comment
period to allow the public the chance to comment on these proposed
DATES: The comment period for the NPRM published in the Federal
Register on December 5, 2017 (82 FR 57390), is reopened. The FAA must
receive comments on this SNPRM by April 27, 2020.
ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Docket: Go to https://www.regulations.gov. Follow
online instructions for sending your comments electronically.
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-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 proposed AD, the European 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 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 FURTHER INFORMATION CONTACT: Matt Fuller, Senior Aviation Safety
Engineer, Safety Management Section, Rotorcraft Standards Branch, FAA,
10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone 817-222-5110;
The FAA invites you to participate in this rulemaking by submitting
written comments, data, or views. The FAA also invites comments
relating to the economic, environmental, energy, or federalism impacts
that might result from adopting the proposals in this document. 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
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
The FAA issued an NPRM to amend 14 CFR part 39 to remove AD 2017-
02-07, Amendment 39-18786 (82 FR 10267, February 10, 2017) ("AD 2017-
02-07") and add a new AD. AD 2017-02-07 applies 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. AD 2017-
02-07 requires a repetitive inspection and a one-time torque of the
hydraulic module plate assembly attachment points (attachment points).
The actions in AD 2017-02-07 are intended to prevent failure of an
attachment point, loss of the hydraulic module plate, and subsequent
loss of control of the helicopter.
The NPRM 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 the single
locking attachment mechanisms with double locking attachment
mechanisms. 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.
Actions Since the NPRM Was Issued
Since the NPRM was issued, Airbus Helicopters revised its service
information by adding 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. The revised
service information also has an alternative clamp effect inspection for
helicopters that have previously installed the double locking
attachment hardware. These additional actions address the unsafe
condition by ensuring the correct torque is applied and the bolts do
not loosen. The FAA is proposing this SNPRM to include these additional
Further, the FAA has corrected an error in the NPRM proposing to
apply a torque of 9 to 10 Nm to the left-hand and right-hand nuts of
each attachment point. This torque adjustment is only necessary for
each forward (not aft) attachment point.
Lastly, the website address for Airbus Helicopters has also
changed. This website address has been updated throughout this SNPRM.
The FAA gave the public the opportunity to comment on the original
NPRM (82 FR 57390, December 5, 2017). The FAA received no comments on
that NPRM or on the determination of the cost to the public.
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 of the
unsafe condition described in its AD. The FAA is proposing this SNPRM
after evaluating all information provided by EASA and determining the
unsafe condition exists and is likely to exist or develop on other
helicopters of these same type designs. Certain changes described above
expand the scope of the original NPRM. As a result, the FAA has
determined that it is necessary to reopen the comment period to provide
additional opportunity for the public to comment on this SNPRM.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Airbus Helicopters Alert Service Bulletin (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
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.
Proposed Requirements of the SNPRM
For helicopters with a hydraulic module plate assembly with the
single locking attachment hardware installed, this proposed AD would
require, within 100 hours time-in-service (TIS), performing a visual
inspection of each attachment point of the hydraulic module plate
assembly for a crack and proper installation, and applying torque to
the nuts of each forward attachment point. Within 300 hours TIS, this
proposed AD would require replacing each single locking attachment
point mechanism with a double locking attachment point mechanism.
For helicopters with a hydraulic module plate assembly with double
locking attachment hardware installed in accordance with Airbus
Helicopters 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, this proposed
AD would require, within 300 hours TIS, inspecting the clamping effect
of the aft joints and torque tightening the bolts. If a bolt can be
turned while applying torque, this proposed AD would require removing
the split pin and self-locking castellated nut from service, inspecting
the bolt for wear and replacing it if necessary, repositioning the aft
grounding strap to the opposite side of the attachment point, replacing
the washer, installing a new self-locking castellated nut, inspecting
the electrical bonding, installing a new split pin, and applying
lacquer to the grounding connection.
Differences Between This SNPRM and the EASA AD
The EASA AD specifies performing the visual inspection of each
attachment point at intervals not exceeding 400 flight hours. This
proposed AD would not require a repetitive inspection. This proposed AD
would require the replacement of each single locking attachment point
mechanism with a double locking attachment point mechanism within 300
hours TIS instead, which would make 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 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
Costs of Compliance
The FAA estimates that this proposed 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 would take 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 four attachment points
would take 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 would take a minimal amount of time and parts
would cost about $48 per attachment point. Installing four double
locking attachment point mechanisms would take a minimal amount of time
and parts would cost about $400 per helicopter and $66,800 for the U.S.
For certain double locking attachment hardware aft joints,
inspecting the clamping effect and applying torque would take 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 would take about 0.5 work-hour and parts would
cost about $15 for an estimated cost of $58 per helicopter.
According to Airbus Helicopters' service information, some of the
costs of this proposed 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.
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
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
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 removing airworthiness directive (AD)
2017-02-07, Amendment 39-18786 (82 FR 10267, February 10, 2017), and
adding the following new AD: