DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2020-0378; Product Identifier 2018-SW-060-AD; Amendment
39-21316; AD 2020-22-20]
Airworthiness Directives; Airbus Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
SUMMARY: The FAA is adopting a new airworthiness directive (AD)
Airbus Helicopters Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA,
AS350D, AS350D1, AS355E, AS355F, AS355F1, AS355F2, AS355N, AS355NP,
EC130B4, and EC130T2 helicopters. This AD requires visually inspecting
each main rotor gearbox (MGB) suspension bar attachment bracket bolt
for missing bolt heads. Depending on the outcome of the visual
inspection, measuring the tightening torque, removing certain parts,
sending photos and reporting information to Airbus Helicopters, and
completing an FAA-approved repair is required. This AD was prompted by
a report of a missing MGB suspension bar attachment bolt head. The
actions of this AD are intended to address an unsafe condition on these
DATES: This AD is effective December 14, 2020.
The Director of the Federal Register approved the incorporation by
reference of certain documents listed in this AD as of December 14,
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
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-2020-0378.
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-2020-
0378; 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
FOR FURTHER INFORMATION CONTACT: Kristi Bradley, Aerospace Engineer,
General Aviation & Rotorcraft Section, International Validation Branch,
FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone 817-222-
5110; email firstname.lastname@example.org.
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
Model AS350B, AS350B1, AS350B2, AS350B3, AS350BA, AS350C, AS350D,
AS350D1, AS355E, AS355F, AS355F1, AS355F2, AS355N, AS355NP, EC130B4,
and EC130T2 helicopters. The NPRM published in the Federal Register on
April 13, 2020, (85 FR 20447). The NPRM proposed to require visually
inspecting each MGB suspension bar attachment bracket for missing bolt
heads. If one bolt head is missing, the proposed AD would require
performing actions specified in the service information including
measuring the tightening torque of the remaining bolts of that bracket,
removing the attachment bracket bolts, washers, and nuts of that
bracket, and sending photos and reporting certain information to Airbus
Helicopters. The proposed AD would also require repairs in accordance
with an FAA-approved method if two or more bolt heads are missing. The
proposed requirements were intended to prevent failure of the MGB
suspension bar attachment bolts due to fatigue.
The NPRM was prompted by EASA AD No. 2018-0152, dated July 18, 2018
(EASA AD 2018-0152), issued by EASA, which is the Technical Agent for
the Member States of the European Union, to correct an unsafe condition
for Airbus Helicopters (formerly Eurocopter, Eurocopter France) Model
AS 350 B, AS 350 D, AS 350 B1, AS 350 B2, AS 350 BA, AS 350 BB, AS 350
B3, EC 130 B4, EC 130 T2, AS 355 E, AS355 F, AS355 F1, AS 355 F2, AS
355 N, and AS355 NP helicopters. EASA advises of a reported occurrence
of a missing MGB suspension bar attachment bolt head.
EASA advises that investigations are ongoing to determine the root
cause of this event. According to Airbus Helicopters, the missing MGB
suspension bar attachment bolt head was discovered during scheduled
maintenance of a Model EC 130 T2 helicopter. EASA states this condition
could lead to fatigue failure of other affected bolts of the same MGB
bracket, possibly resulting in loss of the MGB suspension bar and
consequently loss of helicopter control. As an interim measure to
address this potential unsafe condition, the EASA AD also includes
Model AS 350 B, AS 350 D, AS 350 B1, AS 350 B2, AS 350 BA, AS 350 BB,
AS 350 B3, EC 130 B4, AS 355 E, AS355 F, AS355 F1, AS355 F2, AS355 N,
and AS355 NP helicopters in its applicability.
Accordingly, EASA AD 2018-0152 requires a one-time visual
inspection to check that all MGB suspension bar attachment bracket bolt
heads are present and depending on the outcome, measuring the
tightening torque values of the bolts, removing and sending bolts,
washers, and nuts to Airbus Helicopters, installing new bolts, washers,
and nuts, sending photos and reporting certain information to Airbus
Helicopters, and contacting Airbus Helicopters for approved repair instructions.
EASA states EASA AD 2018-0152 is considered an interim action and further
action may follow.
The FAA gave the public the opportunity to participate in
developing this final rule. The FAA received comments from one
commenter. The following presents the comments received on the NPRM and
the FAA's response to the comments.
The commenter requested that this AD apply to Model AS350B3 and
higher model helicopters, specifically Model AS350B3, AS350B3E,
EC130B4, EC130T2, H125, and H130 helicopters. The commenter stated
that, based on experience with a fleet of AS350BA and AS350B2
helicopters, the commenter has never seen a bolt head break on Model
AS350BA and AS350B2 helicopters.
The FAA disagrees with removing models from the Applicability. The
FAA determined that the unsafe condition exists and is likely to exist
or develop on all the model helicopters included in the Applicability
and is therefore requiring corrective action to address this unsafe
condition on these models.
The commenter requested the manufacturer add the inspection
proposed in the NPRM to the 660-hour ``T'' inspection and also add the
inspection after a certain number of flight hours after installation.
The commenter gave an example of after 165 flying hours.
The FAA disagrees; the commenter provided no technical
justification for changing the compliance times.
Actions Since Issuance of the NPRM
After the NPRM was issued, the FAA discovered that Airbus
Helicopters Model AS350C was inadvertently included in the proposed
Applicability. This helicopter model has a different engine model and
therefore is not subject to the unsafe condition. The FAA has updated
the Applicability section accordingly.
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 issuing this AD after
evaluating all information provided by EASA, reviewing the relevant
information, considering the comments received, and determining the
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 except
for the change described previously. The FAA has determined that this
change is consistent with the intent that was proposed for addressing
the unsafe condition and does not add any additional burden upon the
public than was already proposed in the NPRM except for minor editorial
changes. These minor editorial changes are consistent with the intent
of the proposals in the NPRM and will not increase the economic burden
on any operator nor increase the scope of this AD.
The FAA considers this AD to be an interim action. If final action
is later identified, the FAA might consider further rulemaking.
Differences Between This AD and the EASA AD
The EASA AD applies to Model AS350BB helicopters, whereas this AD
does not because that model is not FAA type-certificated. The EASA AD
directs the operators to contact Airbus Helicopters for repairs if more
than one screw head is missing, whereas this AD does not.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Airbus Helicopter Alert Service Bulletin (ASB) No.
AS350-05.00.92 for Model AS350B, B1, B2, B3, BA, and D helicopters,
non-FAA type-certificated Model AS350BB helicopters, and military Model
AS350L1 helicopters; Airbus Helicopters ASB No. AS355-05.00.79 for
Model AS355E, F, F1, F2, N, and NP helicopters; and Airbus Helicopters
ASB No. EC130-05A028 for Model EC130B4 and T2 helicopters, all Revision
0 and dated July 16, 2018. This service information specifies a one-
time visual inspection using a light source and a mirror, and using an
endoscope for any attachment bolts that are difficult to access, for
the presence of the 16 attachment bracket bolt heads of the 4 MGB
suspension bars. The service information also specifies different
actions depending on the results of the visual inspection.
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 Standard Practices Manual (MTC) 20-02-
05-404, Assembly by screws and nuts Joining, dated May 23, 2017. This
service information specifies instructions for installing screws and
nuts, tightening procedures when installing multiple bolts, tightening
torque check and readjustment procedures, tooling information,
measuring locking torque procedures, standard tightening torque
procedures and values, torque tightening of screws in sandwich panels
information, use of consumable materials and their correction
coefficient values pertaining to screws, nuts, and washers, marking
torque stripes, and re-installation criteria and inspection of
Costs of Compliance
The FAA estimates that this AD affects 1,277 helicopters of U.S.
Registry. The FAA estimates that operators may incur the following
costs in order to comply with this AD. Labor costs are estimated at $85
Inspecting for any missing MGB suspension bar attachment bracket
bolt heads takes about 2 work-hours for an estimated cost of $170 per
helicopter and $217,090 for the U.S. fleet.
Measuring the tightening torque of three MGB suspension bar
attachment bracket bolts and replacing the set of four MGB suspension
bar attachment bracket bolts, washers, and nuts takes about 1 work-hour
and parts cost about $50 for an estimated cost of $135 per helicopter.
Sending photos and reporting required information takes about 1
hour for an estimated cost of $85 per helicopter.
The FAA does not have the data to estimate the costs to do any FAA-
approved repairs if two or more MGB suspension bar attachment bracket
bolt heads are missing.
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 a 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 currently valid OMB Control Number. The OMB
Control Number for this information collection is 2120-0056. Public
reporting for this collection of
information is estimated to be approximately 1 hour per response,
including the time for reviewing instructions, searching existing data
sources, gathering and maintaining the data needed, and completing and
reviewing the collection of information. All responses to this
collection of information are mandatory. Send comments regarding this
burden estimate or any other aspect of this collection of information,
including suggestions for reducing this burden to: Information
Collection Clearance Officer, Federal Aviation Administration, 10101
Hillwood Parkway, 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 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 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
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 adding the following new airworthiness