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44654

Federal Register / Vol. 86, No. 154 / Friday, August 13, 2021 / Proposed Rules
hours TIS, Revision 2 of the service information specifies initial a compliance time of within 5 hours of flight time, whereas this proposed AD
would require initial actions within 5
hours TIS or 30 days after the effective date of this AD, whichever occurs later, instead.
Revision 2 of the service information specifies returning a removed torque tube, whereas this proposed AD would require removing the torque tube from service instead. Revision 2 of the service information specifies completing a Service Operation Report, whereas this proposed AD does not include that requirement.

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Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect 58
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 the torque tube would take a minimal amount of time.
Borescope inspecting the torque tube would take about 1 work-hour for an estimated cost of $85 per helicopter and $4,930 for the U.S. fleet, per inspection cycle.
If required, replacing the torque tube would take about 5 work-hours and parts would cost about $983 for an estimated cost of $1,408 per helicopter.
The FAA has included all known costs in its cost estimate. According to the manufacturer, however, some of the costs of this proposed AD may be covered under warranty, thereby reducing the cost impact on affected operators.
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.

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Regulatory Findings
e Unsafe Condition
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.

This AD was prompted by a report of a spiral crack in the torque tube. The FAA is issuing this AD to prevent failure of a torque tube. The unsafe condition, if not addressed, could result in loss of tail rotor control and subsequent loss of control of the helicopter.

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 39AIRWORTHINESS
DIRECTIVES
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 adding the following new airworthiness directive:

MD Helicopters Inc. MDHI: Docket No.
FAA20210653; Project Identifier AD
202100170R.
a Comments Due Date The FAA must receive comments on this airworthiness directive AD by September 27, 2021.

c Applicability This AD applies to MD Helicopters Inc.
MDHI Model 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, 500N, and 600N helicopters, certificated in any category, with pilot-to-copilot tail rotor torque tube torque tube part number 369H75319/11/13, installed.
d Subject Joint Aircraft Service Component JASC
Code: 6720, Tail Rotor Control System.

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Comply with this AD within the compliance times specified, unless already done.
g Required Actions 1 Using a flashlight and mirror, visually inspect the exterior of the torque tube at the interface of the torque tube and bushing segments, and borescope inspect the interior of the torque tube at the interface of the torque tube and bushing segments for a crack, elongation, and other damage, which may be indicated by any corrosion, pitting, crazing, dents, dings, displacement of material at the bolt hole edge, or fretting of the hole by following the Accomplishment Instructions, paragraphs 2.A.1. through 3.a., of MD
Helicopters Service Bulletin SB369H263R2, SB369D229R2, SB369E129R2, SB369F
119R2, SB500N066R2, or SB600N080R2, each dated March 24, 2021, as applicable to your model helicopter, as follows:
Note 1 to paragraph g1: Scaling of the inner diameter primer or paint may be an indication of a crack.
i For helicopters that have accumulated 600 or less total hours time-in-service TIS, within 100 hours TIS after the effective date of this AD.
ii For helicopters that have accumulated more than 600 total hours TIS, within 5
hours TIS or 30 days after the effective date of this AD, whichever occurs later.
Note 2 to paragraph g1ii: It is advised to limit flights with increased, excessive, or rapid pedal movements before the first instance of the actions required by paragraph g1ii are accomplished.
iii If there is a crack, elongation, or other damage, before further flight, remove the torque tube from service.
2 Thereafter following paragraph g1 of this AD, at intervals not to exceed 300 hours TIS, borescope inspect the interior of the torque tube at the interface of the torque tube and bushing segments as required by paragraph g1 of this AD. If there is a crack, elongation, or other damage, before further flight, remove the torque tube from service.
h Credit for Previous Actions
b Affected ADs None.

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f Compliance
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You may take credit for the instance of the actions required by paragraphs g1i or ii of this AD if you performed corresponding actions before the effective date of this AD
using MD Helicopters Service Bulletin SB369H263, SB369D229, SB369E129, SB369F119, SB500N066, or SB600N080, each dated January 30, 2020, as applicable to your model helicopter, or MD Helicopters Service Bulletin SB369H263R1, SB369D
229R1, SB369E129R1, SB369F119R1, SB500N066R1, or SB600N080R1, each dated May, 15 2020, as applicable to your model helicopter.

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