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[Federal Register Volume 90, Number 19 (Thursday, January 30, 2025)]
[Proposed Rules]
[Pages 8499-8505]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-01949]

========================================================================
Proposed Rules
                                                Federal Register
________________________________________________________________________

This section of the FEDERAL REGISTER contains notices to the public of 
the proposed issuance of rules and regulations. The purpose of these 
notices is to give interested persons an opportunity to participate in 
the rule making prior to the adoption of the final rules.

========================================================================


Federal Register / Vol. 90, No. 19 / Thursday, January 30, 2025 / 
Proposed Rules

[[Page 8499]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2025-0011; Project Identifier AD-2024-00618-R]
RIN 2120-AA64

Airworthiness Directives; Robinson Helicopter Company 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) 
2024-19-11, which applies to all Robinson Helicopter Company Model R44 
and R44 II helicopters. AD 2024-19-11 requires visually inspecting a 
certain flex plate assembly (flex plate) and certain clutch shaft 
forward yokes (yokes), including each flex plate bolt, and depending on 
the results, taking corrective actions. AD 2024-19-11 also requires 
removing certain yokes from service within a specified threshold, or as 
an alternative, performing in-depth inspections. Since the FAA issued 
AD 2024-19-11, it has been determined that clarifications regarding the 
alternative inspections are necessary. This proposed AD would retain 
all the requirements of AD 2024-19-11 and would clarify that the 
alternative inspections are repetitive and add a particular paint 
remover option to use when performing those alternative inspections. 
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 March 17, 
2025.

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 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.
    AD Docket: You may examine the AD docket at regulations.gov under 
Docket No. FAA-2025-0011; 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, any comments received, and other 
information. The street address for Docket Operations is listed above.
    Related Material:
     For Robinson material identified in this proposed AD, 
contact Robinson Helicopter Company, Technical Support Department, 2901 
Airport Drive, Torrance, CA 90505; phone: (310) 539-0508; fax: (310) 
539-5198; email: robinsonheli.com">ts1@robinsonheli.com; website: robinsonheli.com.

FOR FURTHER INFORMATION CONTACT: Eric Moreland, Aviation Safety 
Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone: 
(562) 627-5364; 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 the ADDRESSES section. Include ``Docket No. FAA-2025-0011; 
Project Identifier AD-2024-00618-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 revise 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 
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 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 Eric 
Moreland, Aviation Safety Engineer, FAA, 3960 Paramount Boulevard, 
Lakewood, CA 90712; phone: (562) 627-5364; 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 2024-19-11, Amendment 39-22853 (89 FR 78785, 
September 26, 2024) (AD 2024-19-11), for all Robinson Helicopter 
Company Model R44 and R44 II helicopters. AD 2024-19-11 was prompted by 
reports of a fractured yoke on the main rotor (M/R) drive due to 
fatigue cracking.
    AD 2024-19-11 requires visually inspecting flex plate part number 
(P/N) C947-1, yoke P/N C907-1 or C907-2, as applicable, yoke P/N C908-
1, and each flex plate bolt, and depending on the results, replacing 
parts. AD 2024-19-11 also requires removing yoke P/N C907-1 or C907-2, 
as applicable, from service before reaching a specified threshold or, 
as an alternative to removing the part from service, using a 10X or 
higher power magnifying glass, visual inspecting the yoke and, 
depending on the results, magnetic particle inspecting the yoke or 
replacing parts. The FAA issued AD 2024-19-11 to detect fatigue 
cracking on the yoke, which if not addressed, could result in loss of 
M/R drive and subsequent loss of control of the helicopter.

[[Page 8500]]

Actions Since AD 2024-19-11 Was Issued

    Since the FAA issued AD 2024-19-11, the FAA has determined that 
clarification regarding the alternative yoke inspections and the 
addition of a particular paint remover option to use when performing 
the alternative inspections are necessary. This proposed AD clarifies 
that the alternative inspections are repetitive and adds the option to 
use Bonderite stripper S-ST 5251 instead of Cee-Bee stripper A-292 
since Cee-Bee stripper A-292 could be difficult for some operators to 
obtain.

FAA's Determination

    The FAA is issuing this NPRM after determining that the unsafe 
condition described previously is likely to exist or develop on other 
products of the same type design.

Related Material

    The FAA reviewed Robinson Helicopter Company R44 Maintenance Manual 
and Instructions for Continued Airworthiness, Volume 1, Chapter 2 and 
Chapter 23, dated September 2023, which specifies procedures for 
inspecting the yoke and flex plate of the M/R drive, removing paint, 
applying torque, and performing a magnetic particle inspection.

Proposed AD Requirements in This NPRM

    This proposed AD would retain all requirements of AD 2024-19-11 and 
update the alternative action to repetitively inspect a yoke that has 
reached the specified threshold instead of replacing it.

Costs of Compliance

    The FAA estimates that this AD, if adopted as proposed, would 
affect 1,725 helicopters of U.S. registry. The FAA estimates the 
following costs to comply with this proposed AD. Labor costs are 
estimated at $85 per work-hour.
    Visually inspecting a flex plate would take 0.25 work-hour for an 
estimated cost of $21 per helicopter and $36,225 for the U.S. fleet. If 
required, replacing a flex plate would take 1 work-hour and parts would 
cost $1,240 for an estimated cost of $1,325 per helicopter.
    Visually inspecting a yoke, including inspecting each flex plate 
bolt, would take 1.25 work-hours for an estimated cost of $106 per 
helicopter and $182,850 for the U.S. fleet.
    Replacing a yoke would take 6 work-hours and parts would cost $890 
for an estimated cost of $1,400 per helicopter and $2,415,000 for the 
U.S. fleet, per replacement cycle.
    Alternatively, removing paint and inspecting a yoke using 10X or 
higher power magnifying glass would take 1.5 work-hours for an 
estimated cost of $128 per helicopter. If required, performing a 
magnetic particle inspection would take 1.5 work-hours for an estimated 
cost of $128 per helicopter.
    Applying torque to a set of bolts, nuts, and palnuts would take 1 
work-hour for an estimated cost of $85 per helicopter.

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 above, I certify that the 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 2024-19-11, Amendment 39-22853 (89 
FR 78785, September 26, 2024); and
0
b. Adding the following new airworthiness directive:

Robinson Helicopter Company: Docket No. FAA-2025-0011; Project 
Identifier AD-2024-00618-R.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by March 17, 2025.

(b) Affected ADs

    This AD replaces AD 2024-19-11, Amendment 39-22853 (89 FR 78785, 
September 26, 2024).

(c) Applicability

    This AD applies to Robinson Helicopter Company Model R44 and R44 
II helicopters, certificated in any category.

(d) Subject

    Joint Aircraft System Component (JASC) Code 6310, Engine/
Transmission coupling.

(e) Unsafe Condition

    This AD was prompted by reports of a fractured clutch shaft 
forward yoke (yoke) on the main rotor (M/R) drive due to fatigue 
cracking. The FAA is issuing this AD to detect fatigue cracking on 
the yoke. The unsafe condition, if not addressed, could result in 
loss of M/R drive and subsequent loss of control of the helicopter.

(f) Compliance

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

(g) Required Actions

    (1) Within 100 hours time-in-service (TIS) after the effective 
date of this AD, accomplish the actions required by paragraphs 
(g)(1)(i) through (iii) of this AD.
    (i) Visually inspect forward flex plate assembly part number (P/
N) C947-1 (flex plate) for any loose fasteners, cracks, fretting, 
corrosion, wear, and to ensure that the washers are bonded to both 
sides of each flex plate arm, in the areas depicted in Figure 1 to 
paragraph (g)(1)(i) of this AD. If there is any loose fastener (can 
be moved by hand), crack, fretting, corrosion, or wear that consists 
of the washers not securely bonded to both sides of each flex plate 
arm, before further flight, remove the flex plate from service and 
replace it with an airworthy flex plate.

[[Page 8501]]

    Note 1 to paragraph (g)(1)(i):  The flex plate may be installed 
in order to accomplish the visual inspection.

Figure 1 to Paragraph (g)(1)(i)--Flex Plate Inspection
[GRAPHIC] [TIFF OMITTED] TP30JA25.004

    (ii) Visually inspect yoke P/N C907-1 or C907-2, as applicable, 
and yoke P/N C908-1, for any cracks, corrosion, and fretting. If 
there is any crack, corrosion, or fretting, before further flight, 
remove the yoke from service and replace it with an airworthy yoke, 
and torque each newly-installed bolt, nut, and palnut P/N B330-19 
using the torque value information in Appendix 1 to this AD.
    (iii) Visually inspect each flex plate bolt for any missing or 
unaligned torque stripes, loose fasteners, loose nuts, and to ensure 
that palnuts are installed. If there is a missing or unaligned 
torque stripe, loose fastener (can be moved by hand), loose nut (can 
be turned by hand), or if a palnut is not installed, before further 
flight, remove the associated yoke from service and replace it with 
an airworthy yoke, and torque each newly-installed bolt, nut, and 
palnut P/N B330-19 using the torque value information in Appendix 1 
to this AD.
    (2) Within the compliance times specified in Table 1 to the 
introductory text of paragraph (g)(2) of this AD, accomplish the 
actions required by paragraph (g)(2)(i) of this AD or, as an 
alternative to accomplishing the actions required by paragraph 
(g)(2)(i) of this AD, accomplish the actions required by paragraph 
(g)(2)(ii) of this AD within the same compliance times.
BILLING CODE 4910-13-P

[[Page 8502]]

Table 1 to the Introductory Text of Paragraph (g)(2)
[GRAPHIC] [TIFF OMITTED] TP30JA25.005

[[Page 8503]]

[GRAPHIC] [TIFF OMITTED] TP30JA25.006

BILLING CODE 4910-13-C
    (i) Remove the yoke from service and replace it with an 
airworthy yoke, and torque each newly-installed bolt, nut, and 
palnut P/N B330-19 using the torque value information in Appendix 1 
to this AD, or
    (ii) With yoke P/N C907-1 or C907-2 removed, as applicable, 
remove the paint from the yoke using Cee-Bee stripper A-292 or 
Bonderite stripper S-ST 5251 without using a plastic media abrasive 
paint stripper and accomplish the actions required by paragraphs 
(g)(2)(ii)(A) and (B) of this AD.
    (A) Using 10X or higher power magnifying glass, visually inspect 
the yoke for any crack, seam, lap, shut, and any flaw that is open 
to the surface. If there is any crack, seam, lap, shut, or flaw, 
before further flight, remove the yoke from service and replace it 
with an airworthy yoke, and torque each newly-installed bolt, nut, 
and palnut P/N B330-19 using the torque value information in 
Appendix 1 to this AD.
    (B) If the yoke is not removed from service as a result of the 
actions required by paragraph (g)(2)(ii)(A) of this AD, perform a 
magnetic particle inspection for any crack, seam, lap, shut, and any 
flaw that is open to the surface using a method in accordance with 
FAA-approved procedures. If there is any crack, seam, lap, shut, or 
flaw, before further flight, remove the yoke from service and 
replace it with an airworthy yoke, and torque each newly-installed 
bolt, nut, and palnut P/N B330-19 using the torque value information 
in Appendix 1 to this AD.

(h) Special Flight Permit

    A one-time flight permit may be issued in accordance with 14 CFR 
21.197 and 21.199 to fly to a maintenance area to perform the 
required actions in this AD, provided there are no passengers 
onboard.

(i) Alternative Methods of Compliance (AMOCs)

    (1) The Manager, West Certification 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 West Certification Branch, send it to 
the attention of the person identified in paragraph (j) 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.

(j) Additional Information

    For more information about this AD, contact Eric Moreland, 
Aviation Safety Engineer, FAA, 3960 Paramount Boulevard, Lakewood, 
CA 90712; phone: (562) 627-5364; email: [email protected].

(k) Material Incorporated by Reference

    None.
BILLING CODE 4910-13-P

[[Page 8504]]

Appendix 1 to AD ####-##-####
[GRAPHIC] [TIFF OMITTED] TP30JA25.007

[[Page 8505]]

    Issued on January 23, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2025-01949 Filed 1-29-25; 8:45 am]
BILLING CODE 4910-13-C
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