Rule2024-21921
Airworthiness Directives; Robinson Helicopter Company Helicopters
Primary source
Metadata and text below are from the Federal Register, a public-domain U.S. government work. Always verify the official published version before relying on it for any legal matter.
Published
September 26, 2024
Effective
October 31, 2024
Issuing agencies
Transportation DepartmentFederal Aviation Administration
Abstract
The FAA is adopting a new airworthiness directive (AD) for all Robinson Helicopter Company Model R44 and R44 II helicopters. 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. This AD requires visually inspecting a certain part-numbered flex plate assembly (flex plate) and certain part-numbered yokes, including each flex plate bolt, and depending on the inspection results, removing an affected part from service and replacing an affected part with an airworthy part. This AD also requires removing a certain part-numbered yoke from service after accumulating a certain number of hours time-in-service (TIS) or a certain number of years, or as an alternative to removing the part from service, performing a 10x or higher power magnification visual inspection and, if needed, a magnetic particle inspection. The FAA is issuing this AD to address the unsafe condition on these products.
Full Text
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<title>Federal Register, Volume 89 Issue 187 (Thursday, September 26, 2024)</title>
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[Federal Register Volume 89, Number 187 (Thursday, September 26, 2024)]
[Rules and Regulations]
[Pages 78785-78791]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 2024-21921]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2024-0237; Project Identifier AD-2023-00491-R;
Amendment 39-22853; AD 2024-19-11]
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 adopting a new airworthiness directive (AD) for all
Robinson Helicopter Company Model R44 and R44 II helicopters. 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. This AD requires
visually
[[Page 78786]]
inspecting a certain part-numbered flex plate assembly (flex plate) and
certain part-numbered yokes, including each flex plate bolt, and
depending on the inspection results, removing an affected part from
service and replacing an affected part with an airworthy part. This AD
also requires removing a certain part-numbered yoke from service after
accumulating a certain number of hours time-in-service (TIS) or a
certain number of years, or as an alternative to removing the part from
service, performing a 10x or higher power magnification visual
inspection and, if needed, a magnetic particle inspection. The FAA is
issuing this AD to address the unsafe condition on these products.
DATES: This AD is effective October 31, 2024.
ADDRESSES:
AD Docket: You may examine the AD docket at <a href="http://regulations.gov">regulations.gov</a> under
Docket No. FAA-2024-0237; 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.
Related Material: For Robinson material identified in this AD,
contact Robinson Helicopter Company, Technical Support Department, 2901
Airport Drive, Torrance, CA 90505; phone: (310) 539-0508; fax: (310)
539-5198; email: <a href="/cdn-cgi/l/email-protection#24505715641845044c56414219" http: robinsonheli.com">robinsonheli.com</a>">ts1@<a href="http://robinsonheli.com">robinsonheli.com</a></a>; or at <a href="http://robinsonheli.com">robinsonheli.com</a>.
FOR FURTHER INFORMATION CONTACT: Eric Moreland, Aviation Safety
Engineer, FAA, 3960 Paramount Boulevard, Lakewood, CA 90712; phone:
(562) 627-5364; email: <a href="/cdn-cgi/l/email-protection#befbccd7dd90ec90f3d1ccdbd2dfd0dafed8dfdf90d9d1c8"><span class="__cf_email__" data-cfemail="eeab9c878dc0bcc0a3819c8b828f808aae888f8fc0898198">[email protected]</span></a>.
SUPPLEMENTARY INFORMATION:
Background
After receiving a report of a failed yoke in the M/R drive system,
the FAA issued Special Airworthiness Information Bulletin AIR-22-08,
dated April 11, 2022 (SAIB) to remind owners and operators of any
Robinson Helicopter Company Model R44 helicopters of the importance of
adhering to existing inspection procedures in the applicable operating
handbooks and maintenance manuals. According to Robinson Helicopter
Company, the yoke had fractured due to fatigue cracking and improper
torque at the bolt hole and the yoke cross-section. After the FAA
issued the SAIB, Robinson Helicopter Company reported an additional
incident on a Model R44 helicopter where the yoke was fractured and
separated from the drive train, again due to fatigue cracks and
improper torquing.
Accordingly, the FAA issued a notice of proposed rulemaking (NPRM)
to amend 14 CFR part 39 by adding an AD that would apply to all
Robinson Helicopter Company Model R44 and R44 II helicopters. The NPRM
published in the Federal Register on February 28, 2024 (89 FR 14596).
In the NPRM, the FAA proposed to require visually inspecting a certain
part-numbered flex plate for any loose fasteners, cracks, fretting,
corrosion, wear, and to ensure that the washers are bonded to both
sides of the flex plate arms and depending on the inspection results,
removing the flex plate from service and replacing it with an airworthy
flex plate.
In the NPRM, the FAA also proposed to require visually inspecting
certain part-numbered yokes for any cracks, corrosion, and fretting,
and depending on the inspection results, removing the yoke from service
and replacing it with an airworthy yoke. Additionally, the FAA proposed
to require visually inspecting each yoke bolt for a torque stripe,
loose fastener, loose nut, and to determine if a certain part-numbered
nut and palnut are installed. If there are any missing torque stripes,
loose fasteners, loose nuts, or if certain nuts or palnuts are not
installed, the FAA proposed to require removing the associated yoke
from service and replacing it with an airworthy yoke.
Additionally in the NPRM, the FAA proposed to require removing from
service certain part-numbered yokes that have accumulated more than 12
years or 2,200 total hours TIS, whichever occurs first since first
installation on any helicopter, and replacing them with a certain-part-
numbered yoke that has accumulated less than 2,200 total hours TIS or
12 years, whichever occurs first since first installation on any
helicopter. As an alternative to replacing any yoke that has
accumulated more than 12 years or 2,200 total hours TIS since first
installation on a helicopter, the FAA proposed to allow removing paint
from the yoke and using 10x or higher power magnifying glass to inspect
for any crack, seam, lap, shut, missing cadmium plating, or any flaw
which is open to the surface, and depending on the inspection results,
removing the yoke from service and replacing it with an airworthy yoke.
If the yoke is not replaced as a result of the alternate inspection,
the FAA proposed to require performing a magnetic particle inspection
of the yoke for any crack, seam, lap, shut, or any flaw which is open
to the surface, and depending on the inspection results, removing the
yoke from service and replacing with an airworthy yoke.
Finally, if the yoke is replaced as a result of the actions
required by the NPRM, the FAA proposed to require torquing each bolt,
nut, and palnut using the torque value information in Appendix 1 to the
proposed AD. 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 two commenters. The following
presents the comments received on the NPRM and the FAA's response to
each comment.
Comment Supporting the NPRM
One individual commenter supported the NPRM without change.
Comments Requesting Changes to the Required Actions
Request: Robinson Helicopter Company stated the 2,200 hours TIS
requirement to replace the affected part or to perform the magnetic
particle inspection in the proposed AD corresponds with the engine
overhaul, service life limit, and interval for additional maintenance.
However, Robinson Helicopter Company stated for Model R44 Cadet
helicopters, the hours TIS requirement to replace the affected part or
to perform the magnetic particle inspection is a 2,400 hours TIS
requirement because of that model's more restrictive operating
limitations on maximum takeoff weight and engine power. Therefore,
Robinson Helicopter Company requested the FAA increase the hours TIS
interval for the replacement of the affected part or the magnetic
particle inspection to 2,400 hours TIS for Model R44 Cadet helicopters
to allow the operator to coordinate the airworthiness directive
requirements with other mandatory maintenance requirements.
FAA Response: The FAA partially agrees with the request. The FAA
disagrees with revising this final rule to refer to Model R44 Cadet
helicopters because the ``Cadet'' is not a recognized type-certificated
model on the FAA type certificate data sheet. However, the FAA agrees
to allow Model R44 helicopters having serial numbers (S/N) 30001 and
subsequent (also known as ``Cadet'' helicopters) to have 2,400 hours
TIS to replace an affected part or to perform a magnetic particle
inspection. The FAA has revised paragraphs (g)(2) and (3) of
[[Page 78787]]
this final rule accordingly to reflect that Model R44 helicopters
having S/Ns 30001 and subsequent, on which a yoke replacement as
specified in this final rule was not accomplished is required to remove
that yoke from service and replace it with an airworthy yoke, prior to
the accumulation of 2,400 total hours TIS or within 12 years since
first installation, whichever occurs first.
Request: Robinson Helicopter Company stated paragraph (g)(3)(i) of
the proposed AD requires the yoke to be replaced if there is any
missing cadmium plating. Robinson Helicopter Company stated cadmium
plating provides corrosion protection without complete coverage and
also can be inadvertently removed during installation and removal of
hardware. Robinson Helicopter Company further stated that the
requirement to remove the yoke if there is any missing cadmium plating
will cause the unnecessary removal of many yokes. Therefore, Robinson
Helicopter Company requested the FAA add an exception for cadmium
plating and the removal of the yoke from service due to cadmium
plating.
FAA Response: The FAA agrees and has revised this AD accordingly by
not adopting the inspection and corrective actions associated with
cadmium plating proposed in the NPRM.
Request: Robinson Helicopter Company stated paragraph (g)(1)(iii)
of the proposed AD requires ensuring that nut part number (P/N) D210-6
and palnut P/N B330-19 are installed. Robinson stated that per type
design, only the two bolts on the flex plate assembly have palnut P/N
B330-19 installed. Robinson Helicopter Company stated the wording in
the proposed AD could cause some Model R44 helicopters to replace a
yoke unnecessarily. Robinson Helicopter Company requested the FAA
revise paragraph (g)(1)(iii) of the final rule to only apply to bolts
shared with the flex plate assembly. Robinson Helicopter Company
further stated it is possible some yokes do not have nut P/N D210-6
installed and would therefore also be subject to an unnecessary yoke
replacement. Robinson Helicopter Company requested the FAA revise the
wording of paragraph (g)(1)(iii) in the final rule to remove the
reference to nut P/N D210-6.
FAA Response: The FAA agrees with these requests and revised
paragraph (g)(1)(iii) of this AD to clarify that the inspection area is
only for the flex plate assembly bolts and to remove any references to
nut P/N D210-6.
Conclusion
The FAA reviewed the relevant data, considered any comments
received, and determined that air safety requires adopting this AD as
proposed. Accordingly, the FAA is issuing this AD to address the unsafe
condition on these products. Except for minor editorial changes, any
other changes described previously, and a clarification note added to
paragraph (g)(1)(i) of this final rule, this AD is adopted as proposed
in the NPRM. None of the changes will increase the economic burden on
any operator.
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. This
material also contains the information specified in Appendix 1 to this
AD, which specifies torque values, and Figure 1 to paragraph (g)(1) of
this AD, which depicts the areas for the flex plate inspection.
Costs of Compliance
The FAA estimates that this AD affects 1,725 helicopters of U.S.
registry. The FAA estimates the following costs to comply with this AD.
Labor costs are estimated at $85 per work-hour.
Visually inspecting a flex plate will take approximately 0.25 work-
hour for an estimated cost of $21 per helicopter and $36,225 for the
U.S. fleet.
Visually inspecting a yoke, including inspecting each yoke bolt,
will take approximately 1.25 work-hours for an estimated cost of $106
per helicopter and $182,850 for the U.S. fleet.
Replacing a yoke will take approximately 6 work-hours and parts
will cost approximately $890 for an estimated cost of $1,400 per
helicopter.
Removing paint and inspecting a yoke using 10X or higher power
magnifying glass will take approximately 1.5 work-hours for an
estimated cost of $128 per helicopter.
Performing a magnetic particle inspection will take approximately
1.5 work-hours for an estimated cost of $128 per helicopter.
Applying torque to one bolt, nut, and palnut will take
approximately 1 work-hour for an estimated cost of $85 per hardware
set.
If required, replacing a flex plate will take approximately 1 work-
hour and parts will cost approximately $1,240 for an estimated cost of
$1,325 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.
[[Page 78788]]
Sec. 39.13 [Amended]
0
2. The FAA amends Sec. 39.13 by adding the following new airworthiness
directive:
2024-19-11 Robinson Helicopter Company: Amendment 39-22853; Docket
No. FAA-2024-0237; Project Identifier AD-2023-00491-R.
(a) Effective Date
This airworthiness directive (AD) is effective October 31, 2024.
(b) Affected ADs
None.
(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 (flex plate)
part number (P/N) C947-1 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 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.
Figure 1 to Paragraph (g)(1)(i)--Flex Plate Inspection
[GRAPHIC] [TIFF OMITTED] TR26SE24.000
(ii) Visually inspect yoke P/N C907-1 or C907-2, as applicable
to your model helicopter, 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 using the torque value information in Appendix
1 to this AD.
(iii) Visually inspect each flex plate bolt for a torque stripe,
loose fastener, and a loose nut, and to ensure that palnut P/N B330-
19 is installed. If there is a missing torque stripe, loose fastener
on any nut (can be moved by hand), or if any nut is loose (nut can
be turned by hand), or if palnut P/N B330-19 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 using the torque value information in Appendix
1 to this AD.
(2) For Model R44 helicopters having serial number 0002, or 0004
through 9999 inclusive, except not 1140, and R44 II helicopters
having serial number 1140 or 10001 through 29999 inclusive on which
a yoke replacement as specified in paragraph (g)(1)(ii) or (iii) of
this AD was not accomplished: Prior to the accumulation of 2,200
total hours TIS on any yoke P/N C907-1 or C907-2 or 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, remove that
yoke from service and replace it with an airworthy yoke, and torque
each newly-installed bolt, nut, and palnut using the torque value
information in Appendix 1 to this AD.
(3) For Model R44 helicopters having serial number 30001 and
subsequent, on which a yoke replacement as specified in paragraph
(g)(1)(ii) or (iii) of this AD was not accomplished: Prior to the
accumulation of 2,400 total hours TIS on any yoke P/N C907-1 or
C907-2 or 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, remove that yoke from service and replace it with an
airworthy yoke, and torque each newly-installed bolt, nut, and
palnut using the
[[Page 78789]]
torque value information in Appendix 1 to this AD.
(4) As an alternative to removing the yoke from service as
required by paragraph (g)(2) or (3) of this AD as applicable, remove
yoke P/N C907-1 or C907-2, as applicable to your model helicopter,
remove the paint on the yoke using Cee-Bee stripper A-292, without
using a plastic media abrasive paint stripper, and accomplish
paragraphs (g)(4)(i) and (ii) of this AD, as applicable.
(i) Using 10X or higher power magnifying glass, visually inspect
the yoke for any crack, seam, lap, shut, and any flaw which 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 using the torque value information in Appendix 1 to this
AD.
(ii) If the yoke is not removed from service as a result of the
actions required by paragraph (g)(4)(i) of this AD, inspect it for
any crack, seam, lap, shut, or any flaw which is open to the surface
by performing a magnetic particle inspection 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 with an airworthy yoke, and torque each
newly-installed bolt, nut, and palnut 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 in order 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: <a href="/cdn-cgi/l/email-protection#57161a18141731363679303821"><span class="__cf_email__" data-cfemail="16575b59555670777738717960">[email protected]</span></a>.
(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
For more information about this AD, contact Eric Moreland,
Aviation Safety Engineer, FAA, 3960 Paramount Boulevard, Lakewood,
CA 90712; phone: (562) 627-5364; email: <a href="/cdn-cgi/l/email-protection#93d6e1faf0bdc1bddefce1f6fff2fdf7d3f5f2f2bdf4fce5"><span class="__cf_email__" data-cfemail="5411263d377a067a193b263138353a30143235357a333b22">[email protected]</span></a>.
(k) Material Incorporated by Reference
None.
Appendix 1 to AD 2024-19-11
BILLING CODE 4910-13-P
[[Page 78790]]
[GRAPHIC] [TIFF OMITTED] TR26SE24.001
[[Page 78791]]
Issued on September 19, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft
Certification Service.
[FR Doc. 2024-21921 Filed 9-25-24; 8:45 am]
BILLING CODE 4910-13-C
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