[Federal Register Volume 87, Number 3 (Wednesday, January 5, 2022)]
[Rules and Regulations]
[Pages 385-388]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-28471]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0839; Project Identifier MCAI-2020-01697-R; 
Amendment 39-21877; AD 2021-26-18]
RIN 2120-AA64


Airworthiness Directives; Airbus Helicopters

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule.

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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2020-21-01 
for certain Airbus Helicopters Model AS-365N2, AS 365N3, EC 155B, 
EC155B1, and SA-365N1 helicopters. AD 2020-21-01 required modifying the 
main gearbox (MGB) tail rotor (T/R) drive flange installation. This AD 
was prompted by several reported occurrences of loss of tightening 
torque of the Shur-Lok nut, which serves as a retainer of the MGB T/R 
drive flange. This AD continues to require modifying the MGB T/R drive 
flange installation, and includes additional helicopters in the 
applicability for the required actions. The FAA is issuing this AD to 
address the unsafe condition on these products.

DATES: This AD is effective February 9, 2022.
    The Director of the Federal Register approved the incorporation by 
reference of certain publications listed in this AD as of February 9, 
2022.
    The Director of the Federal Register approved the incorporation by 
reference of certain other publications listed in this AD as of 
November 12, 2020 (85 FR 63440, October 8, 2020).

ADDRESSES: For service information identified in this final rule, 
contact Airbus Helicopters, 2701 North Forum Drive, Grand Prairie, TX 
75052; phone: (972) 641-0000 or (800) 232-0323; fax: (972) 641-3775; or 
at https://www.airbus.com/helicopters/services/support.html. You may 
view this service information at the FAA, Office of the Regional 
Counsel, Southwest Region, 10101 Hillwood Pkwy, Room 6N-321, Fort 
Worth, TX 76177. For information on the availability of this material 
at the FAA, call (817) 222-5110. It is also available at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-
0839.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0839; 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 final rule, the 
European Union Aviation Safety Agency (EASA) AD, any comments received, 
and other information. The 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 
20590.

FOR FURTHER INFORMATION CONTACT: Andrea Jimenez, Aerospace Engineer, 
COS Program Management Section, Operational Safety Branch, Compliance & 
Airworthiness Division, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY 
11590; phone: (516) 228-7330; email: [email protected].

SUPPLEMENTARY INFORMATION:

Background

    The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 
CFR part 39 to supersede AD 2020-21-01,

[[Page 386]]

Amendment 39-21274 (85 FR 63440, October 8, 2020) (AD 2020-21-01). AD 
2020-21-01 applied to certain Airbus Helicopters Model AS-365N2, AS 
365N3, EC 155B, EC155B1, and SA-365N1 helicopters. The NPRM published 
in the Federal Register on September 30, 2021 (86 FR 54139). In the 
NPRM, the FAA proposed to continue to require modifying the MGB T/R 
drive flange installation, and also proposed to include additional 
helicopters in the applicability for the required actions. The NPRM was 
prompted by several reported occurrences of loss of tightening torque 
of the Shur-Lok nut, which serves as a retainer of the MGB T/R drive 
flange.
    EASA AD 2020-0287, dated December 21, 2020 (EASA AD 2020-0287), was 
issued by EASA, which is the Technical Agent for the Member States of 
the European Union, to correct an unsafe condition for certain AS 365 
N2, AS 365 N3, SA 365 C1, SA 365 C2, SA 365 C3, SA 365 N and SA 365 N1 
helicopters; and all EC 155 B and EC 155 B1 helicopters. Model SA 365 
C3 helicopters are not certificated by the FAA and are not included on 
the U.S. type certificate data sheet; this AD therefore does not 
include those helicopters in the applicability. EASA AD 2020-0287 
supersedes EASA AD 2020-0212, dated October 5, 2020, which required 
modification of the MGB T/R drive flange installation. 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 antirotation tabs engaged 
into two slots at the end of the MGB output shaft pinion. EASA states 
this condition could lead to the loosening of the Shur-Lok nut and 
disengagement of the Shur-Lok nut threads, possibly resulting in 
reduction of T/R drive control, rear transmission vibrations, and 
subsequent reduced control of the helicopter.
    Accordingly, EASA AD 2020-0287 retains the modification of the MGB 
T/R drive flange installation. EASA AD 2020-0287 also includes 
additional helicopters in the applicability for the required actions 
(Model SA-365C1, SA-365C2, and SA-365N helicopters on which Airbus 
Helicopters modification 0763B64 has been embodied; and Model EC 155B 
and EC155B1 helicopters without modification 0763B64 embodied).

Discussion of Final Airworthiness Directive

Comments

    The FAA received comments from three commenters. The commenters 
were an individual who made a statement about the applicability; an 
individual who expressed support and favor for the NPRM; and an 
anonymous commenter, who had a question about the applicability. The 
following presents the comments received on the NPRM and the FAA's 
response to each comment.

Request for Clarification of Applicability

    An individual stated the opinion that all helicopters should be 
subject to the same rules, a preference for unity under the law, and 
that it is unfair to have different rules for different helicopters. An 
anonymous commenter asked why the NPRM is only applicable to Airbus 
Helicopters and not other current and modern models of helicopters. The 
FAA infers that the commenters may be suggesting that this AD should 
apply to all helicopter models. No further justification was given.
    The FAA agrees to clarify the applicability. Each FAA AD has a 
specific applicability, and this FAA AD reflects the applicability of 
EASA AD 2020-0287. This AD only addresses the models specified in the 
EASA AD that are affected by the unsafe condition. Helicopters and the 
systems that support the design are varied, and because of design 
variances between manufacturers, may or may not be subject to an unsafe 
condition. Therefore, in crafting a rule, the FAA specifically works to 
apply rulemaking only to the models and systems that are affected. 
Otherwise, the FAA may be creating arbitrary regulations, unnecessary 
work, and burdensome costs for the operators of the unaffected 
helicopters. There is no further need to expand the applicability of 
this AD to other helicopter models due to the likelihood that the type 
designs are different and therefore not subject to the unsafe 
condition. If information is received indicating other models are 
affected by the unsafe condition, the FAA will consider further 
rulemaking. The FAA has made no changes to this AD.

Conclusion

    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 about the 
unsafe condition described in its AD. The FAA reviewed the relevant 
data, considered the comments received, and determined that air safety 
requires adopting this AD as proposed. Accordingly, the FAA is issuing 
this AD to address the unsafe condition on these helicopters. Except 
for minor editorial changes, this AD is adopted as proposed in the 
NPRM. None of the changes will increase the economic burden on any 
operator.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed the following service information.
    Airbus Helicopters Alert Service Bulletin (ASB) No. AS365-63.00.26, 
Revision 0, dated July 22, 2020, for Model AS365N helicopters and non 
FAA-type certificated military Model AS365Fs helicopters; and Airbus 
Helicopters ASB No. SA365-65.52, Revision 1, dated July 22, 2020, for 
Model SA-365C1 and SA-365C2 helicopters and non FAA-type certificated 
Model SA-365C3 helicopters. This service information specifies 
procedures for modifying the MGB T/R drive flange installation, which 
include installing a rear (aft) output stop between the T/R drive 
flange and T/R drive shaft. These documents are distinct since they 
apply to different helicopter models.
    This AD also requires Airbus Helicopters ASB No. AS365-63.00.19, 
Revision 1, dated January 31, 2019; and Airbus Helicopters ASB No. 
EC155-63A013, Revision 1, dated January 31, 2019; which the Director of 
the Federal Register approved for incorporation by reference as of 
November 12, 2020 (85 FR 63440, October 8, 2020).
    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.

Differences Between This AD and the EASA AD

    EASA AD 2020-0287 specifies compliance times of 600 flight hours or 
a certain time frame (months). However, this AD only requires the 
compliance time of 600 hours time-in-service.

Costs of Compliance

    The FAA estimates that this AD affects 53 helicopters of U.S. 
Registry. Labor rates are estimated at $85 per work-hour. Based on 
these numbers, the FAA estimates the following costs to comply with 
this AD.

[[Page 387]]



                                                 Estimated Costs
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                                                                                                 Cost on U.S.
             Action                   Labor cost          Parts cost       Cost per product        operators
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Modification (46 helicopters)     14 work-hours x     $2,704............  $3,894............  $179,124
 (retained actions from AD         $85 per hour =
 2020[dash]21[dash]01).            $1,190.
Modification (new action).......  14 work-hours x     Up to 18,474......  Up to 19,664......  Up to 1,042,192
                                   $85 per hour =
                                   $1,190.
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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

    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) 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 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:

    Authority:  49 U.S.C. 106(g), 40113, 44701.


Sec.  39.13  [Amended]

0
2. The FAA amends Sec.  39.13 by:
0
a. Removing Airworthiness Directive 2020-21-01, Amendment 39-21274 (85 
FR 63440, October 8, 2020); and
0
b. Adding the following new airworthiness directive:

2021-26-18 Airbus Helicopters: Amendment 39-21877; Docket No. FAA-
2021-0839; Project Identifier MCAI-2020-01697-R.

(a) Effective Date

    This airworthiness directive (AD) is effective February 9, 2022.

(b) Affected ADs

    This AD replaces AD 2020-21-01, Amendment 39-21274 (85 FR 63440, 
October 8, 2020) (AD 2020-21-01).

(c) Applicability

    This AD applies to the Airbus Helicopters model helicopters, 
certificated in any category, as identified in paragraphs (c)(1) 
through (3) of this AD.
    (1) Model AS-365N2, AS 365 N3, and SA-365N1, all serial numbers 
on which Airbus Helicopters modification 0763B64 has been embodied, 
except those on which Airbus Helicopters modification 0763C81 has 
been embodied.
    (2) Model SA-365C1, SA-365C2, and SA-365N, all serial numbers on 
which Airbus Helicopters modification 0763B64 has been embodied.
    (3) Model EC 155B and EC155B1, all serial numbers, except those 
on which Airbus Helicopters modification 0763C81 has been embodied.

(d) Subject

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

(e) Unsafe Condition

    This AD was prompted by several reported occurrences of loss of 
tightening torque of the Shur-Lok nut, which serves as a retainer of 
the main gear box (MGB) tail rotor (T/R) drive flange. The FAA is 
issuing this AD to detect and address loss of tightening torque of 
the Shur-Lok nut. The unsafe condition, if not addressed, could 
result in loosening of the Shur-Lok nut, possibly resulting in 
disengagement of the Shur-Lok nut threads, reduction of T/R drive 
control, rear transmission vibrations, and subsequent reduced 
control of the helicopter.

(f) Compliance

    Comply with this AD within the compliance times specified, 
unless already done.

(g) Required Actions

    This paragraph restates the requirements of paragraph (e) of AD 
2020-21-01 with no changes. Within 600 hours time-in-service after 
November 12, 2020 (the effective date of AD 2020-21-01):
    (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, Revision 1); 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, Revision 1, and by following the 
Accomplishment Instructions, paragraph 3.B.2.b, of ASB AS365-
63.00.19, Revision 1.
    (2) For Model EC 155B and EC155B1 helicopters with modification 
0763B64 embodied:
    (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, Revision 1); 
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, Revision 1, and by following the Accomplishment 
Instructions, paragraph 3.B.2.b, of ASB EC155-63A013, Revision 1.
    Note 1 to paragraph (g)(2)(ii): ASB EC155-63A013, Revision 1 
refers to the ``aft output stop'' as ``rear output stop.''

(h) New Required Actions

    For Model SA-365C1, SA-365C2, and SA-365N helicopters; and Model 
EC 155B and EC155B1 helicopters without modification 0763B64 
embodied: Within 600 hours time-in-service after the effective date 
of this AD, modify the MGB T/R drive flange installation, in 
accordance with paragraph

[[Page 388]]

3.B.2., ``Procedure,'' of the Accomplishment Instructions of the 
applicable service information specified in paragraphs (h)(1) 
through (3) of this AD, except as specified in paragraph (i) of this 
AD.
    (1) Airbus Helicopters ASB SA365-65.52, Revision 1, dated July 
22, 2020.
    (2) Airbus Helicopters ASB AS365-63.00.26, Revision 0, dated 
July 22, 2020.
    (3) ASB EC155-63A013, Revision 1.

(i) Exceptions to Service Information

    Where the service information identified in paragraph (h) of 
this AD specifies to discard certain parts, this AD requires 
removing those parts from service.

(j) Special Flight Permits

    Special flight permits, as described in 14 CFR 21.197 and 
21.199, are not allowed.

(k) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, International Validation Branch, FAA, has the 
authority to approve AMOCs for this AD, if requested using the 
procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, 
send your request to your principal inspector or local Flight 
Standards District Office, as appropriate. If sending information 
directly to the manager of the International Validation Branch, send 
it to the attention of the person identified in paragraph (l)(1) of 
this AD. Information may be emailed to: [email protected].
    (2) Before using any approved AMOC, notify your appropriate 
principal inspector, or lacking a principal inspector, the manager 
of the local flight standards district office/certificate holding 
district office.

(l) Related Information

    (1) For more information about this AD, contact Andrea Jimenez, 
Aerospace Engineer, COS Program Management Section, Operational 
Safety Branch, Compliance & Airworthiness Division, FAA, 1600 
Stewart Ave., Suite 410, Westbury, NY 11590; phone: (516) 228-7330; 
email: [email protected].
    (2) The subject of this AD is addressed in European Union 
Aviation Safety Agency (EASA) AD 2020-0287, dated December 21, 2020. 
You may view the EASA AD at https://www.regulations.gov in Docket 
No. FAA-2021-0839.

(m) Material Incorporated by Reference

    (1) The Director of the Federal Register approved the 
incorporation by reference (IBR) of the service information listed 
in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.
    (2) You must use this service information as applicable to do 
the actions required by this AD, unless the AD specifies otherwise.
    (3) The following service information was approved for IBR on 
February 9, 2022.
    (i) Airbus Helicopters Alert Service Bulletin (ASB) No. AS365-
63.00.26, Revision 0, dated July 22, 2020.
    (ii) Airbus Helicopters ASB No. SA365-65.52, Revision 1, dated 
July 22, 2020.
    (4) The following service information was approved for IBR on 
November 12, 2020 (85 FR 63440, October 8, 2020).
    (i) Airbus Helicopters ASB No. AS365-63.00.19, Revision 1, dated 
January 31, 2019.
    (ii) Airbus Helicopters ASB No. EC155-63A013, Revision 1, dated 
January 31, 2019.
    (5) For Airbus Helicopters service information identified in 
this AD, contact Airbus Helicopters, 2701 North Forum Drive, Grand 
Prairie, TX 75052; phone: (972) 641-0000 or (800) 232-0323; fax: 
(972) 641-3775; or at https://www.airbus.com//services/support.html.
    (6) You may view this service information at the FAA, Office of 
the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., Room 
6N-321, Fort Worth, TX 76177. For information on the availability of 
this material at the FAA, call (817) 222-5110.
    (7) You may view this service information that is incorporated 
by reference at the National Archives and Records Administration 
(NARA). For information on the availability of this material at 
NARA, email: [email protected], or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.

    Issued on December 15, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-28471 Filed 1-4-22; 8:45 am]
BILLING CODE 4910-13-P


