AD 2018-19-10
Applicability
| Type | Manufacturer | Model | Details |
|---|---|---|---|
| aircraft | Airbus Helicopters | AS355E | Airworthiness Directives; Airbus Helicopters |
| aircraft | Airbus Helicopters | AS355F | Airworthiness Directives; Airbus Helicopters |
| aircraft | Airbus Helicopters | AS355F1 | Airworthiness Directives; Airbus Helicopters |
| aircraft | Airbus Helicopters | AS355F2 | Airworthiness Directives; Airbus Helicopters |
| aircraft | Airbus Helicopters | AS355N | Airworthiness Directives; Airbus Helicopters |
Unsafe Condition
Degradation of a main gearbox (MGB) oil cooler fan assembly bearing, which could result in loss of MGB and engine oil cooling function, loss of the rear transmission, and subsequent loss of control of the helicopter.
AI-generated summary from the source AD text. Verify against the official source before acting.
Required Actions
Measure the tail rotor (T/R) drive vibration level without balancing the T/R drive, and record the amplitude value. Clean the oil cooler fan. Measure the T/R drive vibration level without balancing the T/R drive, and record the amplitude value. Calculate the difference between the two amplitude values. If the difference is greater than 0.75 inch per second (ips), before further flight, replace each oil cooler fan assembly bearing. After the effective date of this AD, do not install an oil cooler fan assembly bearing with more than 0 hours TIS unless the requirements of this AD have been accomplished.
AI-generated summary from the source AD text. Verify against the official source before acting.
Compliance Time
Within 165 hours time-in-service (TIS)
AI-generated summary from the source AD text. Verify against the official source before acting.
Affected Aircraft
Airbus Helicopters Model AS355E, AS355F, AS355F1, AS355F2, and AS355N helicopters, certificated in any category.
AI-generated summary from the source AD text. Verify against the official source before acting.
Federal Register Abstract
We are adopting a new airworthiness directive (AD) for Airbus Helicopters Model AS355E, AS355F, AS355F1, AS355F2, and AS355N helicopters. This AD requires measuring a vibration level in the tail rotor (T/R) drive. This AD was prompted by reports of bearing degradation. The actions of this AD are intended to prevent an unsafe condition on these helicopters.
Document Text
Show stored source text (verify against official source)
[Federal Register Volume 83, Number 186 (Tuesday, September 25, 2018)]
[Rules and Regulations]
[Pages 48366-48368]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2018-20487]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2018-0438; Product Identifier 2017-SW-062-AD; Amendment
39-19410; AD 2018-19-10]
RIN 2120-AA64
Airworthiness Directives; Airbus Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: We are adopting a new airworthiness directive (AD) for Airbus
Helicopters Model AS355E, AS355F, AS355F1, AS355F2, and AS355N
helicopters. This AD requires measuring a vibration level in the tail
rotor (T/R) drive. This AD was prompted by reports of bearing
degradation. The actions of this AD are intended to prevent an unsafe
condition on these helicopters.
DATES: This AD is effective October 30, 2018.
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 <a href="http://www.helicopters.airbus.com/website/en/ref/Technical-Support_73.html">http://www.helicopters.airbus.com/website/en/ref/Technical-Support_73.html</a>. You may review 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 <a href="http://www.regulations.gov">http://www.regulations.gov</a> by searching for and locating Docket No. FAA-2018-
0438; or in person at Docket Operations
[[Page 48367]]
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 (EASA) AD, the economic evaluation, any comments received, and
other information. The street address for Docket Operations (phone:
800-647-5527) 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, Aviation Safety
Engineer, Regulations and Policy Section, Rotorcraft Standards Branch,
FAA, 10101 Hillwood Pkwy., Fort Worth, TX 76177; telephone (817) 222-
5110; email <a href="/cdn-cgi/l/email-protection#0476656b2a616071747163656a706d446265652a636b72"><span class="__cf_email__" data-cfemail="c8baa9a7e6adacbdb8bdafa9a6bca188aea9a9e6afa7be">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Discussion
On May 17, 2018, at 83 FR 22886, the Federal Register published our
notice of proposed rulemaking (NPRM), which proposed to amend 14 CFR
part 39 by adding an AD that would apply to Airbus Helicopters Model
AS355E, AS355F, AS355F1, AS355F2, and AS355N helicopters. The NPRM
proposed to require measuring the T/R drive vibration level without
balancing, cleaning the fan, and repeating the vibration level
measurement. If the difference between the two amplitude values is
greater than 0.75 inch per second (ips), the NPRM proposed to require
replacing each T/R fan bearing. The proposed requirements were intended
to prevent degradation of the main gearbox (MGB) oil cooler fan bearing
(bearing), which could result in loss of MGB and engine oil cooling
function, loss of the rear transmission, and subsequent loss of control
of the helicopter.
The NPRM was prompted by AD No. 2017-0159, dated August 25, 2017,
issued by EASA, which is the Technical Agent for the Member States of
the European Union, to correct an unsafe condition for Airbus
Helicopters Model AS355E, AS355F, AS355F1, AS355F2, and AS355N
helicopters. EASA advises of two occurrences on Model AS355 military
helicopters in which the MGB bearing installed on the T/R drive shaft
experienced significant degradation. EASA states that while
investigation has not determined the cause of the failures, this
condition may also occur on other Model AS355 helicopters due to design
commonality. According to EASA, this condition, if not detected and
corrected, could result in loss of MGB and engine oil cooling function,
loss of the rear transmission, and subsequent loss of control of the
helicopter. To address this unsafe condition and as an interim measure,
the EASA AD requires two vibration level measurements of the forward
portion of the tail rotor drive line, one before and one after cleaning
the MGB oil cooler fan, and replacing the bearings if excessive level
or level trends are detected. The EASA AD also specifies that after the
effective date of the AD, only those MGB oil cooler fan assembly
bearings that are new or that have passed the vibration level
measurements may be installed.
Comments
We gave the public the opportunity to participate in developing
this AD, but we did not receive any comments on the NPRM.
FAA's Determination
These helicopters have been approved by the aviation authority of
France and are approved for operation in the United States. Pursuant to
our bilateral agreement with France, EASA, its technical
representative, has notified us of the unsafe condition described in
the EASA AD. We are issuing this AD because we evaluated all
information provided by EASA and determined the unsafe condition exists
and is likely to exist or develop on other helicopters of the same type
design and that air safety and the public interest require adopting the
AD requirements as proposed.
Interim Action
We consider this AD to be an interim action. The manufacturer is
currently developing a terminating action for the unsafe condition
described in this AD. If a terminating action is identified, we may
consider further rulemaking then.
Related Service Information
Airbus Helicopters has issued Alert Service Bulletin No. AS355-
05.00.77, Revision 0, dated July 3, 2017, which contains procedures for
checking the condition of the fan assembly bearings by measuring the
vibration levels of the first section of the T/R drive.
Costs of Compliance
We estimate that this AD affects 104 helicopters of U.S. Registry.
We estimate that operators may incur the following costs in order to
comply with this AD.
At an average labor rate of $85 per work-hour, measuring the
vibration levels requires about 5 work-hours, for a cost of $425 per
helicopter and $44,200 for the U.S. fleet. If required, replacing both
fan assembly bearings requires about 8 work-hours, and required parts
cost $1,064, for a cost of $1,744 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.
We are 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.
Regulatory Findings
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 12866;
(2) Is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979);
(3) Will not affect intrastate aviation in Alaska to the extent
that it justifies making a regulatory distinction; and
(4) 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.
We prepared an economic evaluation of the estimated costs to comply
with this AD and placed it in the AD docket.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
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
0
1. The authority citation for part 39 continues to read as follows:
[[Page 48368]]
Authority: 49 U.S.C. 106(g), 40113, 44701.
Sec. 39.13 [Amended]
0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive (AD):
2018-19-10 Airbus Helicopters: Amendment 39-19410; Docket No. FAA-
2018-0438; Product Identifier 2017-SW-062-AD.
(a) Applicability
This AD applies to Airbus Helicopters Model AS355E, AS355F,
AS355F1, AS355F2, and AS355N helicopters, certificated in any
category.
(b) Unsafe Condition
This AD defines the unsafe condition as degradation of a main
gearbox (MGB) oil cooler fan assembly bearing. This condition could
result in loss of MGB and engine oil cooling function, loss of the
rear transmission, and subsequent loss of control of the helicopter.
(c) Effective Date
This AD becomes effective October 30, 2018.
(d) Compliance
You are responsible for performing each action required by this
AD within the specified compliance time unless it has already been
accomplished prior to that time.
(e) Required Actions
(1) Within 165 hours time-in-service (TIS):
(i) Measure the tail rotor (T/R) drive vibration level without
balancing the T/R drive, and record the amplitude value.
(ii) Clean the oil cooler fan.
(iii) Measure the T/R drive vibration level without balancing
the T/R drive, and record the amplitude value.
(iv) Calculate the difference between the two amplitude values.
If the difference is greater than 0.75 inch per second (ips), before
further flight, replace each oil cooler fan assembly bearing.
(2) After the effective date of this AD, do not install an oil
cooler fan assembly bearing with more than 0 hours TIS unless the
requirements of this AD have been accomplished.
(f) Alternative Methods of Compliance (AMOCs)
(1) The Manager, Safety Management Section, Rotorcraft Standards
Branch, FAA, may approve AMOCs for this AD. Send your proposal to:
Rao Edupuganti, Aviation Safety Engineer, Regulations and Policy
Section, Rotorcraft Standards Branch, FAA, 10101 Hillwood Pkwy.,
Fort Worth, TX 76177; telephone (817) 222-5110; email <a href="/cdn-cgi/l/email-protection#6a53472b393d472c3e3d472b27252947380f1b1f0f191e192a0c0b0b440d051c"><span class="__cf_email__" data-cfemail="e6dfcba7b5b1cba0b2b1cba7aba9a5cbb483979383959295a6808787c8818990">[email protected]</span></a>.
(2) For operations conducted under a 14 CFR part 119 operating
certificate or under 14 CFR part 91, subpart K, we suggest that you
notify your principal inspector, or lacking a principal inspector,
the manager of the local flight standards district office or
certificate holding district office, before operating any aircraft
complying with this AD through an AMOC.
(g) Additional Information
(1) Airbus Helicopters Alert Service Bulletin No. AS355-
05.00.77, Revision 0, dated July 3, 2017, which is not incorporated
by reference, contains additional information about the subject of
this AD. For service information identified in this AD, 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 <a href="http://www.helicopters.airbus.com/website/en/ref/Technical-Support_73.html">http://www.helicopters.airbus.com/website/en/ref/Technical-Support_73.html</a>. You may review a copy of the service information at
the FAA, Office of the Regional Counsel, Southwest Region, 10101
Hillwood Pkwy., Room 6N-321, Fort Worth, TX 76177.
(2) The subject of this AD is addressed in European Aviation
Safety Agency (EASA) AD No. 2017-0159, dated August 25, 2017. You
may view the EASA AD on the internet at <a href="http://www.regulations.gov">http://www.regulations.gov</a>
in Docket No. FAA-2018-0438.
(h) Subject
Joint Aircraft Service Component (JASC) Code: 6510, Tail Rotor
Driveshaft.
Issued in Fort Worth, Texas, on September 12, 2018.
Scott A. Horn,
Deputy Director for Regulatory Operations, Compliance & Airworthiness
Division, Aircraft Certification Service.
[FR Doc. 2018-20487 Filed 9-24-18; 8:45 am]
BILLING CODE 4910-13-P
Source: Official FAA Source ↗
Retrieved: Apr 6, 2026
Rights: U.S. Government Public Domain
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