[Federal Register Volume 86, Number 193 (Friday, October 8, 2021)]
[Proposed Rules]
[Pages 56220-56225]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2021-21955]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2021-0872; Project Identifier MCAI-2021-00312-R]
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 supersede Airworthiness Directive (AD) 
2020-11-05, which applies to all Airbus Helicopters Model EC120B 
helicopters. AD 2020-11-05 requires repetitive inspections of the tail 
rotor (TR) hub body for cracks and applicable corrective actions if 
necessary, and repetitive replacement of the attachment bolts, washers, 
and nuts of the TR hub body. This proposed AD would retain certain 
requirements of AD 2020-11-05, add repetitive inspections, require 
additional corrective actions, and update applicable service 
information. The FAA is proposing this AD to address the unsafe 
condition on these products.

DATES: The FAA must receive comments on this proposed AD by November 
22, 2021.

ADDRESSES: You may send comments, using the procedures found in 14 CFR 
11.43 and 11.45, by any of the following methods:
     Federal eRulemaking Portal: Go to https://www.regulations.gov. Follow the instructions for submitting comments.
     Fax: (202) 493-2251.
     Mail: U.S. Department of Transportation, Docket 
Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New 
Jersey Avenue SE, Washington, DC 20590.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    For service information identified in this NPRM, 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 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.

Examining the AD Docket

    You may examine the AD docket at https://www.regulations.gov by 
searching for and locating Docket No. FAA-2021-0872; 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 
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: Andrea Jimenez, Aerospace Engineer, 
COS Program Management Section, Operational Safety Branch, Compliance & 
Airworthiness Division, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY 
11590; telephone (516) 228-7330; email [email protected].

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-2021-0872; Project Identifier 
MCAI-2021-00312-R'' 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

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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 Andrea Jimenez, Aerospace Engineer, 
COS Program Management Section, Operational Safety Branch, Compliance & 
Airworthiness Division, FAA, 1600 Stewart Ave., Suite 410, Westbury, NY 
11590; telephone (516) 228-7330; email [email protected]. Any 
commentary that the FAA receives which is not specifically designated 
as CBI will be placed in the public docket for this rulemaking.

Background

    The FAA issued AD 2020-11-05, Amendment 39-21130 (85 FR 31042, May 
22, 2020) (AD 2020-11-05), for Airbus Helicopters Model EC120B 
helicopters, all serial numbers. AD 2020-11-05 requires repetitive 
inspections of the TR hub body for cracks and applicable corrective 
actions if necessary, and repetitive replacement of the attachment 
bolts, washers, and nuts of the TR hub body. AD 2020-11-05 was prompted 
by EASA AD 2019-0272R1, dated November 18, 2019 (EASA AD 2019-0272R1), 
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 EC120 B 
helicopters. EASA advised that an inspection of the TR hub body 
revealed a recurring loss of tightening torque on several attachment 
bolts. This condition, if not addressed, could result in cracking and 
potential loss of the TR drive and consequent loss of yaw control of 
the helicopter.
    Accordingly, EASA AD 2019-0272R1 required repetitive inspections of 
the TR hub body for cracks and applicable corrective actions if 
necessary, as well as repetitive replacement of the associated 
attachment bolts, washers, and nuts.

Actions Since AD 2020-11-05 Was Issued

    Since the FAA issued AD 2020-11-05, EASA issued AD 2021-0069, dated 
March 11, 2021 (EASA AD 2021-0069), which supersedes EASA AD 2019-
0272R1. EASA advises that further detailed analysis showed that a loss 
of tightening torque in the interface between the TR hub body and 
splined flange creates the risk of crack initiation from a fretting 
area located on the TR hub body and splined flange or on the TR hub 
body and flange bolts. Accordingly, EASA AD 2021-0069 retains the 
requirements of EASA AD 2019-0272R1 and requires additional repetitive 
detailed inspections of the interface between the TR hub body part 
number (P/N) C642A0100103 and the splined flange. Depending on the 
inspection results, EASA AD 2021-0069 requires accomplishment of 
applicable corrective actions.

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 about the 
unsafe condition described in its AD. The FAA is proposing this AD 
after evaluating all known relevant information and determining that 
the unsafe condition described previously is likely to exist or develop 
on other helicopters of the same type designs.

Related Service Information Under 1 CFR Part 51

    The FAA reviewed Airbus Helicopters Emergency Alert Service 
Bulletin 05A020, Revision 2, dated February 8, 2021 (ASB 05A020 Rev 2). 
This service information specifies procedures for repetitive 
inspections of the TR hub body for cracks and the TR spline flange for 
cracks and fretting and the appropriate corrective actions.
    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 retain some of the requirements of AD 2020-
11-05, and would require, within 15 hours time-in-service (TIS) or 7 
days, whichever occurs first, performing repetitive inspections of the 
TR hub body for a crack and depending on the inspection results, 
removing the affected parts from service. This proposed AD would also 
require inspecting the TR spline flange for corrosion, impacts, 
fretting, wear, and a crack and depending on the inspection results, 
removing the TR splined flange from service. For helicopters with 9,000 
or more total hours TIS or with unknown total hours TIS, this proposed 
AD would require, within 15 hours TIS or 7 days, whichever occurs 
first, and thereafter at intervals not to exceed 1,000 hours TIS, 
removing from service any bolt, washer, and nut installed on the TR hub 
body, replacing them with airworthy parts, inspecting the TR splined 
flange, and depending on the inspection results, removing the TR 
splined flange from service. This proposed AD would also require, for 
helicopters with less than 9,000 total hours TIS, within 1,000 hours 
TIS or before accumulating 9,000 total hours TIS, whichever occurs 
first, and thereafter at intervals not to exceed 1,000 hours TIS, 
removing from service any bolt, washer, and nut installed on the TR hub 
body replacing them with airworthy parts, inspecting the TR splined 
flange, and depending on the inspection results, removing the TR 
splined flange from service. This proposed AD would also prohibit the 
installation of a certain part-numbered TR hub body unless certain 
actions have been accomplished.

Differences Between This Proposed AD and EASA AD 2021-0069

    EASA AD 2021-0069 uses flight hours (FH) for certain compliance 
times, whereas this proposed AD uses hours TIS. EASA AD 2021-0069 
retains the compliance time of November 1, 2019 for certain actions, 
which is the effective date of EASA AD 2019-0272R1, whereas this 
proposed AD would require compliance as of the effective date of the 
proposed AD.
    Where Note 1 of EASA AD 2021-0069 allows a non-cumulative tolerance 
of 100 hours TIS to be applied to the compliance times for the initial 
replacement of bolts, washers, and nuts (Table 1 of EASA AD 2021-0069) 
to allow for synchronization of the required inspections with other 
maintenance tasks, this proposed AD would not allow a non-cumulative 
tolerance of 100 hours TIS to be applied to the compliance times.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 89 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 proposed AD.
    Visually inspecting each TR hub body for a crack would take about 
0.25 work-hour for an estimated cost of $22 per inspection and $1,958 
for the U.S. fleet.
    Visually inspecting each TR spline flange for corrosion, impacts, 
fretting, wear, and a crack would take about 0.25 work-hour for an 
estimated cost of $22 per inspection and $1,958 for the U.S. fleet.
    Replacing a TR hub body would take about 2 work-hours and parts 
would cost about $16,417 for an estimated cost of $16,587 per TR hub 
body replacement.

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    Replacing a TR spline flange would take about 0.5 work-hour and 
parts would cost about $2,950 for an estimated cost of $2,993 per TR 
spline flange replacement.
    Replacing a bolt, washer, and nut would take about 0.5 work-hour 
and parts would cost about $68 for an estimated cost of $111 per 
replacement.

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

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 2020-11-05, Amendment 39-21130 (85 
FR 31042, May 22, 2020); and
0
b. Adding the following new airworthiness directive:

Airbus Helicopters: Docket No. FAA-2021-0872; Project Identifier 
MCAI-2021-00312-R.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) action by November 22, 2021.

(b) Affected ADs

    This AD replaces AD 2020-11-05, Amendment 39-21130 (85 FR 31042, 
May 22, 2020) (AD 2020-11-05).

(c) Applicability

    This AD applies to Airbus Helicopters Model EC120B helicopters, 
certificated in any category, all serial numbers.

(d) Subject

    Joint Aircraft Service Component (JASC) Code: 6400, Tail rotor 
system.

(e) Unsafe Condition

    This AD was prompted by a report of recurrent loss of tightening 
torque on several attachment bolts on the tail rotor (TR) hub body. 
The FAA is issuing this AD to detect cracking and fretting, which if 
not addressed, could result in potential loss of the TR drive and 
consequent loss of yaw control of the helicopter.

(f) Compliance

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

(g) Required Actions

    (1) Within 15 hours time-in-service (TIS) or 7 days, whichever 
occurs first after the effective date of this AD, and thereafter at 
intervals not to exceed 15 hours TIS, using a light source and 
mirror, visually inspect TR hub body part number (P/N) C642A0100103 
for a crack in the entire inspection area depicted in Figure 1 of 
Airbus Helicopters Emergency Alert Service Bulletin 05A020 Revision 
2, dated February 8, 2021 (ASB 05A020 Rev 2). If there is a crack, 
before further flight, perform the actions in paragraphs (g)(1)(i) 
and (ii) of this AD.
    (i) Remove the TR hub body and each bolt, washer, and nut 
installed on the TR hub body from service and replace with airworthy 
parts.
    (ii) Inspect the TR splined flange for corrosion, impacts, 
fretting, wear, and a crack in the areas identified in Figure 2 of 
this AD. If the condition of the part (including corrosion, impacts, 
fretting, wear, or cracks) exceeds the criteria as specified in 
Figure 1 of this AD, before further flight, remove the splined 
flange from service and replace with an airworthy part.

    Note 1 to paragraph (g)(1)(ii):  You may refer to ``Detailed 
Check--Splined Flange,'' Task 64-21-00, 6-5, Airbus Aircraft 
Maintenance Manual (AMM), dated October 15, 2020 which pertains to 
the TR splined flange inspection.

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    (2) For helicopters with 9,000 or more total hours TIS, or with 
unknown total hours TIS, within 15 hours TIS or 7 days, whichever 
occurs first after the effective date of this AD, and thereafter at 
intervals not to exceed 1,000 hours TIS, remove each bolt, washer, 
and nut installed on the TR hub body from service and replace with 
airworthy parts and perform the actions in paragraph (g)(1)(ii) of 
this AD.
    (3) For helicopters with less than 9,000 total hours TIS, within 
1,000 hours TIS or before accumulating 9,000 total hours TIS, 
whichever occurs first after the effective date of this AD, and 
thereafter at intervals not to exceed 1,000 hours TIS, remove each 
bolt, washer, and nut installed on the TR hub body from service and 
replace with airworthy parts and perform the actions in paragraph 
(g)(1)(ii) of this AD.
    (4) As of the effective date of this AD, do not install TR hub 
body P/N C642A0100103 on any helicopter, unless the actions of 
paragraph (g)(1) of this AD have been accomplished.

(h) Special Flight Permits

    A special flight permit may be permitted provided that there are 
no passengers onboard.

(i) 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 (j)(1) of 
this AD.

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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.

(j) 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; telephone (516) 228-
7330; email [email protected].
    (2) For service information identified in this AD, 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 this referenced 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.
    (3) The subject of this AD is addressed in European Union 
Aviation Safety Agency (EASA) AD 2021-0069, dated March 11, 2021. 
You may view the EASA AD on the internet at https://www.regulations.gov in Docket No. FAA-2021-0872.

    Issued on October 1, 2021.
Lance T. Gant,
Director, Compliance & Airworthiness Division, Aircraft Certification 
Service.
[FR Doc. 2021-21955 Filed 10-7-21; 8:45 am]
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