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Federal Register / Vol. 86, No. 193 / Friday, October 8, 2021 / Proposed Rules 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.

Authority for This Rulemaking Title 49 of the United States Code specifies the FAAs 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 Agencys 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.

Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.

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.

The Proposed Amendment
f Compliance
Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 14 CFR part 39 as follows:

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

PART 39AIRWORTHINESS
DIRECTIVES

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 g1i 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 g1ii: You may refer to Detailed CheckSplined Flange, Task 642100, 65, Airbus Aircraft Maintenance Manual AMM, dated October 15, 2020 which pertains to the TR splined flange inspection.

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,
jspears on DSK121TN23PROD with PROPOSALS1

d Subject
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.

VerDate Sep<11>2014

16:42 Oct 07, 2021

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List of Subjects in 14 CFR Part 39

1. The authority citation for part 39
continues to read as follows:

Authority: 49 U.S.C. 106g, 40113, 44701.
39.13

Amended
2. The FAA amends 39.13 by:
a. Removing Airworthiness Directive 20201105, Amendment 3921130 85
FR 31042, May 22, 2020; and b. Adding the following new airworthiness directive:

Airbus Helicopters: Docket No. FAA2021
0872; Project Identifier MCAI2021
00312R.
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 20201105, Amendment 3921130 85 FR 31042, May 22, 2020 AD 20201105.
c Applicability This AD applies to Airbus Helicopters Model EC120B helicopters, certificated in any category, all serial numbers.

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Joint Aircraft Service Component JASC
Code: 6400, Tail rotor system.
e Unsafe Condition
g Required Actions
BILLING CODE 491013P

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