Document ID: FAA-2020-0410-0001
Agency: faa
Document Type: Proposed Rule
Title: Airworthiness Directives: Airbus Helicopters
Posted Date: 2020-04-23T04:00Z

[Federal Register Volume 85, Number 79 (Thursday, April 23, 2020)]
[Proposed Rules]
[Pages 22688-22690]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2020-08583]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2020-0410; Product Identifier 2019-SW-030-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 certain Airbus Helicopters Model AS-365N2, AS 365N3, EC 155B, 
EC155B1, and SA-365N1 helicopters. This proposed AD would require 
modifying the main gearbox (MGB) tail rotor (T/R) drive flange 
installation. This proposed AD was prompted by several reported 
occurrences of loss of tightening torque of the Shur-Lok nut, which 
serves as a retainer of the T/R drive flange. The actions of this 
proposed AD are intended to address an unsafe condition on these 
products.

DATES: The FAA must receive comments on this proposed AD by June 22, 
2020.

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.

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-
0410; 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 Union Aviation Safety Agency (previously 
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.

[[Page 22689]]

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; 
email matthew.fuller@faa.gov.

SUPPLEMENTARY INFORMATION: 

Comments Invited

    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 
time.
    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 
comments received.

Discussion

    EASA, which is the Technical Agent for the Member States of the 
European Union, has issued EASA AD No. 2019-0046, dated March 11, 2019 
(EASA AD 2019-0046), to correct an unsafe condition for Airbus 
Helicopters (formerly Eurocopter, Eurocopter France, Aerospatiale) 
Model SA 365 N1, AS 365 N2, AS 365 N3, EC 155 B, and EC 155 B1 
helicopters, all serial numbers, with modification 0763B64 installed, 
except those with 0763C81 installed.
    EASA advises of reported occurrences of loss of tightening torque 
of the Shur-Lok nut, which serves as a retainer of the T/R drive flange 
of the MGB. EASA also advises of subsequent investigation that 
determined that these occurrences were the result of failure of the 
Shur-Lok nut locking function, which is normally ensured by two anti-
rotation tabs engaged into two slots at the end of the MGB output shaft 
pinion. EASA states this condition could lead to the loosening and 
disengagement of the Shur-Lok nut threads, possibly resulting in 
reduction of T/R drive control, rear transmission vibrations, and 
subsequent loss of control of the helicopter.
    To address this unsafe condition, EASA issued a series of ADs, 
initially with EASA AD No. 2014-0165, dated July 14, 2014 (EASA AD 
2014-0165), which required a one-time inspection of the radial play 
inside the T/R drive flange and the condition of the Shur-Lok nut. 
Shortly after, EASA issued EASA AD No. 2014-0179, dated July 25, 2014 
(EASA AD 2014-0179) to supersede EASA AD 2014-0165. EASA AD 2014-0179 
retained the requirements of EASA AD 2014-0165 and expanded the 
applicability of helicopters affected by the unsafe condition. EASA 
later revised EASA AD 2014-0179 to Revision 1, dated July 29, 2014, to 
revise the applicability and specify updated related service 
information, and again to Revision 2, dated April 11, 2016 (EASA AD 
2014-0179R2), to reduce the applicability and specify additional 
updated related service information. Since EASA issued EASA AD 2014-
0179R2, another occurrence was reported that involved an on-ground loss 
of T/R synchronization, resulting from disengagement of the Shur-Lok 
nut. This additional occurrence prompted EASA to issue EASA AD 2019-
0046 to require installation of modification 07 63C81, which consists 
of installing a rear output stop with 5 spigots on the T/R shaft 
flexible coupling. According to Airbus Helicopters, the 5 spigots will 
come into contact with the row of 5 bolt heads of the front T/R shaft 
if the T/R drive flange moves backwards. This contact limits backward 
displacement of the T/R drive flange and subsequently prevents T/R 
drive flange disengagement.

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. AS365-63.00.19, for Model AS365N, N1, N2, and N3 helicopters and 
non FAA-type certificated military Model AS365F, Fi, Fs, K, and K2 
helicopters; and Airbus Helicopters ASB No. EC155-63A013 for Model 
EC155B and B1 helicopters, both Revision 1 and dated January 31, 2019. 
This service information specifies procedures for modification 0763C81 
to install a rear (aft) output stop between the T/R drive flange and T/
R drive shaft.
    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

    This proposed AD would require compliance with certain procedures 
specified in the manufacturer's service information. This proposed AD 
would require, within 600 hours time-in-service, modifying the MGB T/R 
drive flange installation by removing the sliding flange from the 
flexible coupling and installing the sliding flange with aft output 
stop part number 365A32-7836-20 added, as per helicopter model and 
configuration. This proposed AD would also require removing from 
service certain washers, degreasing the bolt threads, applying a 
sealant between the interlay mating surfaces, and applying torque to 
the nuts.

Costs of Compliance

    The FAA estimates that this proposed AD affects 46 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.
    Modifying the MGB T/R drive flange installation would take about 14 
work-hours and parts would cost about $2,704 for an estimated cost of 
$3,894 per helicopter and $179,124 for the U.S. fleet.

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

[[Page 22690]]

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. 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 
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

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive (AD):

Airbus Helicopters: Docket No. FAA-2020-0410; Product Identifier 
2019-SW-030-AD.

(a) Applicability

    This AD applies to Airbus Helicopters Model AS-365N2, AS 365N3, 
EC 155B, EC155B1, and SA-365N1 helicopters, certificated in any 
category, with modification 0763B64 installed, except those with 
modification 0763C81.

(b) Unsafe Condition

    This AD defines the unsafe condition as loss of tightening 
torque of the Shur-Lok nut, which serves as a retainer of the tail 
rotor (T/R) drive flange of the main gearbox. This condition could 
result in loss of the Shur-Lok nut, possibly resulting in 
disengagement of the T/R drive flange, reduction of T/R drive 
control, rear transmission vibrations, and subsequent loss of 
control of the helicopter.

(c) Comments Due Date

    The FAA must receive comments by June 22, 2020.

(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

    Within 600 hours time-in-service:
    (1) For Model AS-365N2, AS 365N3, and SA-365N1 helicopters:
    (i) Without removing the tail drive shaft flange (a), remove the 
sliding flange (b) from the flexible coupling (c) as shown in Detail 
``B'' of Figure 1, PRE MOD, of Airbus Helicopters Alert Service 
Bulletin (ASB) No. AS365-63.00.19, Revision 1, dated January 31, 
2019 (ASB AS365-63.00.19); replace the 3 bolts (d) and remove from 
service the 3 washers (e).
    (ii) Install the sliding flange (b) with aft output stop (1) 
part number (P/N) 365A32-7836-20 as shown in Detail ``B'' of Figure 
1, POST MOD, of ASB AS365-63.00.19 and by following the 
Accomplishment Instructions, paragraph 3.B.2.b, of ASB AS365-
63.00.19.
    (2) For Model EC 155B and EC155B1 helicopters:
    (i) Without removing the Shur-Lok nut (a), remove the sliding 
flange (b) from the flexible coupling (c) as shown in Detail ``B'' 
of Figure 1, PRE MOD, of Airbus Helicopters ASB No. EC155-63A013, 
Revision 1, dated January 31, 2019 (ASB EC155-63A013); replace the 3 
bolts (d) and remove from service the 3 washers (e).
    (ii) Install the sliding flange (b) with aft output stop (1) P/N 
365A32-7836-20 as shown in Detail ``B'' of Figure 1, POST MOD, of 
ASB EC155-63A013 and by following the Accomplishment Instructions, 
paragraph 3.B.2.b, of ASB EC155-63A013.

    Note 1 to paragraph (e)(2)(ii) of this AD:  ASB EC155-63A013 
refers to the ``aft output stop'' as ``rear output stop.''

(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: 
Matt Fuller, Senior Aviation Safety Engineer, Safety Management 
Section, Rotorcraft Standards Branch, FAA, 10101 Hillwood Pkwy., 
Fort Worth, TX 76177; telephone 817-222-5110; email 9-ASW-FTW-AMOC-Requests@faa.gov.
    (2) For operations conducted under a 14 CFR part 119 operating 
certificate or under 14 CFR part 91, subpart K, the FAA suggests 
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

    The subject of this AD is addressed in European Union Aviation 
Safety Agency (previously European Aviation Safety Agency) (EASA) AD 
No. 2019-0046, dated March 11, 2019. You may view the EASA AD on the 
internet at https://www.regulations.gov in the AD Docket.

(h) Subject

    Joint Aircraft Service Component (JASC) Code: 6500, Tail Rotor 
Drive System.

    Issued on April 17, 2020.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2020-08583 Filed 4-22-20; 8:45 am]
 BILLING CODE 4910-13-P