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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2021-0197; Project Identifier 2018-SW-107-AD]
RIN 2120-AA64
Airworthiness Directives; Airbus Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD)
for Airbus Helicopters Model EC 155B and EC155B1 helicopters. This
proposed AD would require replacing the main gearbox (MGB), or as an
alternative, replacing the epicyclic reduction gear module for certain
serial numbered planet gear assemblies installed on the MGB. This
proposed AD would also require inspecting the MGB magnetic plugs, MGB
filter, and oil sump for particles. Depending on the outcome of these
inspections, this proposed AD would require further inspections and
replacing certain parts. This proposed AD would also prohibit
installing certain parts. This proposed AD was prompted by the failure
of an MGB second stage planet gear. The actions of this proposed AD are
intended to correct an unsafe condition on these helicopters.
DATES: The FAA must receive comments on this proposed AD by September
7, 2021.
ADDRESSES: You may send comments by any of the following methods:
Federal eRulemaking Docket: Go to https://www.regulations.gov. Follow
the online instructions for sending your comments electronically.
Fax: (202) 493-2251.
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.
For service information identified in this proposed rule, contact
Airbus Helicopters, 2701 North 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.
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-
0197; 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 NPRM, the European Aviation Safety Agency (now European Union
Aviation Safety Agency) (EASA) AD, any comments received, and other
information. The street address for Docket Operations is listed above.
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 rao.edupuganti@faa.gov.
SUPPLEMENTARY INFORMATION:
Comments Invited
The FAA invites you to send any written relevant data, views, or
arguments about this proposal. Send your comments to an address listed
under ADDRESSES. Include "Docket No. FAA-2021-0197; Project Identifier
2018-SW-107-AD" at the beginning of your comments. The most helpful
comments reference a specific portion of the proposal, explain the
reason for any recommended change, and include supporting data. The FAA
will consider all comments received by the closing date and may amend
this proposal because of those comments.
Except for Confidential Business Information (CBI) as described in
the following paragraph, and other information as described in 14 CFR
11.35, the FAA will post all comments received, without change, to
https://www.regulations.gov, including any personal information you
provide. The agency will also post a report summarizing each
substantive verbal contact received about this NPRM.
Confidential Business Information
CBI is commercial or financial information that is both customarily
and actually treated as private by its owner. Under the Freedom of
Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public
disclosure. If your comments responsive to this NPRM contain commercial
or financial information that is customarily treated as private, that
you actually treat as private, and that is relevant or responsive to
this NPRM, it is important that you clearly designate the submitted
comments as CBI. Please mark each page of your submission containing
CBI as "PROPIN." The FAA will treat such marked submissions as
confidential under the FOIA, and they will not be placed in the public
docket of this NPRM. Submissions containing CBI should be sent to 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
rao.edupuganti@faa.gov. Any commentary that the FAA receives which is
not specifically designated as CBI will be placed in the public docket
for this rulemaking.
Background
EASA, which is the Technical Agent for the Member States of the
European Union, has issued EASA AD 2018-0263, dated December 7, 2018
(EASA AD 2018-0263), to correct an unsafe condition for Airbus
Helicopters Model EC 155 B and EC 155 B1 helicopters. EASA advises that
after an accident on a Model EC225 helicopter, an investigation
revealed the failure of an MGB second stage planet gear. EASA states
that one of the two types of planet gear used in the MGB epicyclic
module is subject to higher outer race contact pressures and therefore
is more susceptible to spalling and cracking. EASA AD 2018-0263
consequently requires repetitive inspections of the MGB magnetic plugs,
the MGB filer, and the oil sump for particles, and depending on the
results of those inspections, removing or replacing certain parts. EASA
AD 2018-0263 also requires reducing the life limit of Type Z planet
gear assemblies. EASA AD 2018-0263 also requires, if certain gear
assemblies are installed, either replacing the MGB or replacing the
epicyclic reduction gear. Finally EASA AD 2018-0263 prohibits
installing a Type Y planet gear assembly or an MGB with a Type Y planet
gear assembly on any helicopter.
FAA's Determination
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 AD
after evaluating all known relevant information and determining that an
unsafe condition is likely to exist or develop on other products of the
same type designs.
Related Service Information Under 1 CFR Part 51
The FAA reviewed Airbus Helicopters Alert Service Bulletin ASB No.
EC155-05A034, Revision 5, dated December 4, 2018 (ASB EC155-05A34 Rev
5) for Model EC 155 helicopters, which specifies periodic inspections
of the MGB magnetic plugs, the MGB filter, and the oil sump for
particles. ASB EC155-05A34 Rev 5 also specifies identifying the type of
gear assembly installed in the MGB and replacing any Type Y planet gear
assembly within 50 hours time-in-service (TIS). For Type Z gear
assemblies that have logged less than 1,800 hours TIS since new, this
service information specifies replacing the gear assembly before
exceeding 1,800 total hours TIS, and for Type Z gear assemblies that
have logged 1,800 or more total hours TIS, replacing the gear assembly
within 600 hours TIS.
The FAA also reviewed Airbus Helicopters Service Bulletin SB No.
EC155-63-016, Revision 4, dated July 26, 2018, for Model EC 155
helicopters. This service information specifies procedures for
replacing the MGB epicyclic reduction gear without removing the MGB.
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.
Proposed AD Requirements in This NPRM
This proposed AD would require for helicopters with at least one
Type Y planet gear assembly with a certain serial number (S/N)
installed, or at least one Type Z planet gear assembly with a certain
S/N installed, within 10 hours TIS after the effective date of this AD
and thereafter at intervals not to exceed 10 hours TIS, inspecting the
MGB magnetic plugs for particles. If there are particles, the proposed
AD would require further inspections and analyses, and replacing the
MGB, depending on the type and the size of the particles.
This proposed AD would also require for helicopters with a Type Y
planet gear assembly with a certain S/N installed, within 25 hours TIS
after the effective date of this AD, inspecting the MGB filter for
particles. If there are particles, this proposed AD would require
further inspections and analyses, and replacing the MGB, depending on
the type and the size of the particles. This proposed AD would require
for helicopters with at least one Type Y planet gear assembly with a
certain S/N installed, within 50 hours TIS after the effective date of
this AD, replacing the MGB. As an alternative to replacing the MGB,
this proposed AD would allow replacing the epicyclic reduction gear in
the affected MGB.
Additionally, this proposed AD would require, for helicopters
without any Type Y planet gear assembly but at least one Type Z planet
gear assembly with a certain S/N installed, replacing the MGB within 50
hours TIS after the effective date of this AD or before any planet gear
assembly accumulates 1,800 total hours TIS, whichever occurs later. As
an alternative to replacing the MGB, this proposed AD would allow
replacing the epicyclic reduction gear in the affected MGB.
This proposed AD would require, for helicopters with at least one
Type Z planet gear with a certain S/N installed, within certain
compliance times specified in the figures in this AD, inspecting the
MGB filter and inspecting the oil sump for particles. If there are
particles this proposed AD would require further inspections and
analyses, and replacing the MGB, depending on the type and the size of
the particles.
This proposed AD would prohibit installing an MGB with a certain
serial numbered Type Y planet gear assembly and this proposed AD would
also prohibit installing a Type Y planet gear assembly with a certain
S/N on any helicopter.
This proposed AD would also prohibit installing certain serial
numbered Type Z planet gear assemblies that have accumulated 1,800 or
more total hours TIS and prohibit installing an MGB with certain serial
numbered Type Z planet gear assemblies that have accumulated 1,800 or
more total hours TIS.
Finally, this proposed AD would prohibit installing an MGB if the
type of the planet gear assembly cannot be determined and would also
prohibit installing any planet gear assembly if the type cannot be
determined.
Differences Between This Proposed AD and the EASA AD
EASA AD 2018-0263 specifies compliance times based on flight hours
and calendar dates. This proposed AD would set compliance times based
on hours TIS or before further flight. EASA AD 2018-0263 allows a pilot
to inspect the MGB magnetic plugs for particles, while this proposed AD
would not. For helicopters with at least one affected Type Z planet
gear assembly that has accumulated 1,800 or more total hours TIS
installed, EASA AD 2018-0263 requires replacing the MGB or epicyclic
reduction gear within 600 flight hours after March 16, 2018, whereas
this proposed AD would require either of those replacements within 50
hours TIS after the effective date of this proposed AD instead. If
16NCD13 particles are present, EASA AD 2018-0263 requires taking a 1
liter sample of oil and returning it to Airbus Helicopters and removing
the MGB for depot-level inspection, whereas this proposed AD would
require replacing the MGB instead.
Interim Action
The FAA considers this proposed AD to be an interim action. If
final action is later identified, the FAA might consider further
rulemaking then.
Costs of Compliance
The FAA estimates that this proposed AD would affect 14 helicopters
of U.S. Registry. The FAA estimates that operators may incur the
following costs in order to comply with this proposed AD. Labor costs
are estimated at $85 per work-hour.
Inspecting the magnetic plugs for particle deposits would take
about 1 work-hour for an estimated cost of $85 per helicopter per
inspection cycle.
Inspecting the MGB filter and oil sump for particle deposits would
take about 1 work-hour for an estimated cost of $85 per helicopter per
inspection cycle.
Replacing an MGB would take about 42 work-hours, and parts would
cost about $295,000 (overhauled) for an estimated total cost of
$298,570 per helicopter.
Replacing the epicyclic reduction gear would take about 56 work-
hours and parts would cost about $11,404 for an estimated total cost of
$16,164 per helicopter.
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 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 12866,
2. Would not affect intrastate aviation in Alaska, and
3. Would 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.
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 adding the following new airworthiness
directive:
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