[Federal Register Volume 90, Number 108 (Friday, June 6, 2025)]
[Rules and Regulations]
[Pages 24050-24054]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2025-10097]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2025-0011; Project Identifier AD-2024-00618-R;
Amendment 39-23053; AD 2025-11-07]
RIN 2120-AA64
Airworthiness Directives; Robinson Helicopter Company Helicopters
AGENCY: Federal Aviation Administration (FAA), DOT.
ACTION: Final rule.
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SUMMARY: The FAA is superseding Airworthiness Directive (AD) 2024-19-11
for all Robinson Helicopter Company Model R44 and R44 II helicopters.
AD 2024-19-11 required 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 required 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 AD requires the actions of AD 2024-19-
11 and clarifies that the alternative inspections are repetitive and
adds a particular paint remover option to use when performing those
alternative inspections. The FAA is issuing this AD to address the
unsafe condition on these products.
DATES: This AD is effective July 11, 2025.
ADDRESSES:
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 final rule, 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: Eric Moreland, Aviation Safety
Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone:
(562) 627-5364; email: [email protected].
SUPPLEMENTARY INFORMATION:
Background
The FAA issued a notice of proposed rulemaking (NPRM) to amend 14
CFR part 39 to supersede AD 2024-19-11, Amendment 39-22853 (89 FR
78785, September 26, 2024) (AD 2024-19-11). AD 2024-19-11 applied to
all Robinson Helicopter Company Model R44 and R44 II helicopters. The
NPRM published in the Federal Register on January 30, 2025 (90 FR
8499). The NPRM was prompted by reports of a fractured yoke on the main
rotor (M/R) drive due to fatigue cracking. In the NPRM, the FAA
proposed to continue to require 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. The FAA is
issuing this AD to address the unsafe condition on these products.
Discussion of Final Airworthiness Directive
Comments
The FAA received comments from three commenters. Commenters
included two individual commenters and Robinson Helicopter Company. The
following presents the comments received on the NPRM and the FAA's
response to each comment.
One individual commenter supported the NPRM without change.
Request To Change the Applicable Paint Stripper
One individual commenter requested the FAA revise the required
paint stripper from Bonderite S-ST 5251 to Bonderite S-ST 5351.
The FAA agrees and has revised paragraph (g) of this AD
accordingly.
Request To Clarify Compliance Times
Robinson Helicopter Company stated a yoke that has undergone a
magnetic particle inspection per paragraph (g)(2)(ii)(B) [of the
proposed AD], should be allowed to be installed, per the proposed AD
and that clarification would be helpful to state that ``first
installation'' also refers to the first installation after completion
of a magnetic particle inspection. Robinson Helicopter Company
requested the FAA revise the wording in Table 1 of the proposed AD to
include the wording ``first installation after a magnetic particle
inspection.''
[[Page 24051]]
The FAA agrees. The FAA has determined that adding the wording
``after a magnetic particle inspection'' would help clarify that the
compliance time also applies to a yoke being installed after a magnetic
particle inspection. The FAA has revised Table 1 of this final rule.
Conclusion
The FAA reviewed the relevant data, considered any comments
received, and determined that air safety requires adopting the AD as
proposed. Accordingly, the FAA is issuing this AD to address the unsafe
condition on these products. Except for minor editorial changes and any
other changes described previously, this AD is adopted as proposed in
the NPRM. None of the changes will increase the economic burden on any
operator.
Costs of Compliance
The FAA estimates that this AD affects 1,725 helicopters of U.S.
registry. Labor rates are estimated at $85 per hour. Based on these
numbers, the FAA estimates the following costs to comply with this AD.
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, takes 1.25 work-hours for an estimated cost of $106 per
helicopter and $182,850 for the U.S. fleet.
Replacing a yoke takes 6 work-hours and parts will 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 takes 1.5 work-hours for an estimated
cost of $128 per helicopter. If required, performing a magnetic
particle inspection takes 1.5 work-hours for an estimated cost of $128
per helicopter.
Applying torque to a set of bolts, nuts, and palnuts takes 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
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 2024-19-11, Amendment 39-22853 (89
FR 78785, September 26, 2024); and
0
b. Adding the following new airworthiness directive:
2025-11-07 Robinson Helicopter Company: Amendment 39-23053; Docket
No. FAA-2025-0011; Project Identifier AD-2024-00618-R.
(a) Effective Date
This airworthiness directive (AD) is effective July 11, 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 consequent 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.
Note 1 to paragraph (g)(1)(i): The flex plate may be installed
in order to accomplish the visual inspection.
Note 2 to paragraph (g)(1)(i): Robinson Helicopter Company R44
Maintenance Manual and Instructions for Continued Airworthiness,
Volume 1, Chapter 2 and Chapter 23, dated September 2023, contains
information related to this AD.
[[Page 24052]]
[GRAPHIC] [TIFF OMITTED] TN06JN25.000
(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.
Table 1 to the Introductory Text of Paragraph (g)(2)
------------------------------------------------------------------------
Helicopter groups Compliance times
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For Model R44 helicopters Prior to accumulating 2,200 total hours
having serial number 0002, TIS on any yoke P/N C907-1 or C907-2 or
or 0004 through 9999 within 12 years since first installation
inclusive, except not 1140, of yoke P/N C907-1 or C907-2 on any
and R44 II helicopters helicopter, whichever occurs first; or
having serial number 1140 or within 100 hours TIS after the effective
10001 through 29999 date of this AD; whichever occurs later,
inclusive. and thereafter before accumulating 2,200
total hours TIS on any yoke P/N C907-1
or C907-2 or within 12 years since first
installation after replacement or after
the inspection of yoke P/N C907-1 or
C907-2 as required in paragraph
(g)(2)(ii)(B) of this AD, on any
helicopter, whichever occurs first.
For Model R44 helicopters Prior to accumulating 2,400 total hours
having serial number 30001 TIS on any yoke P/N C907-1 or C907-2 or
and subsequent. within 12 years since first installation
of yoke P/N C907-1 or C907-2 on any
helicopter, whichever occurs first; or
within 100 hours TIS after the effective
date of this AD; whichever occurs later,
and thereafter before accumulating 2,400
total hours TIS on any yoke P/N C907-1
or C907-2 or within 12 years since first
installation after replacement or after
the inspection of yoke P/N C907-1 or
C907-2 as required in paragraph
(g)(2)(ii)(B) of this AD, on any
helicopter, whichever occurs first.
------------------------------------------------------------------------
(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 5351 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,
[[Page 24053]]
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)(1) of this
AD and email 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
(1) 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].
(2) For material identified in this AD that is not incorporated
by reference, 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.
(k) Material Incorporated by Reference
None.
Appendix 1 to AD 2025-11-07
BILLING CODE 4910-13-C
[[Page 24054]]
[GRAPHIC] [TIFF OMITTED] TN06JN25.001
Issued on May 29, 2025.
Steven W. Thompson,
Acting Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2025-10097 Filed 6-5-25; 8:45 am]
BILLING CODE 4910-13-P