[Federal Register Volume 89, Number 40 (Wednesday, February 28, 2024)]
[Proposed Rules]
[Pages 14596-14600]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2024-03970]


 ========================================================================
 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.
 
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 

  Federal Register / Vol. 89, No. 40 / Wednesday, February 28, 2024 / 
Proposed Rules  

[[Page 14596]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2024-0237; Project Identifier AD-2023-00491-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 adopt a new airworthiness directive (AD) 
for all Robinson Helicopter Company Model R44 and R44 II helicopters. 
This proposed 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 proposed AD would require visually inspecting a certain 
part-numbered flex plate assembly (flex plate) and certain part-
numbered yokes, including each yoke bolt, and depending on the 
inspection results, removing an affected part from service and 
replacing an affected part with an airworthy part. This proposed AD 
would also require 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 
proposing this AD to address the unsafe condition on these products.

DATES: The FAA must receive comments on this proposed AD by April 15, 
2024.

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-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 NPRM, any comments received, and other 
information. The street address for Docket Operations is listed above.
    Related Service Information: For service information identified in 
this NPRM, 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; or at 
robinsonheli.com. You may view this service information at the FAA, 
Office of the Regional Counsel, Southwest Region, 10101 Hillwood Pkwy., 
Room 6N-321, Fort Worth, TX 76177. For information on the availability 
of this material at the FAA, call (817) 222-5110.

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 ADDRESSES. Include ``Docket No. FAA-2024-0237; Project Identifier 
AD-2023-00491-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 amend 
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

    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

[[Page 14597]]

proposes to adopt a new AD for all Robinson Helicopter Company Model 
R44 and R44 II helicopters to ensure adequate inspection and 
maintenance of all driveshaft yokes. This condition, if not addressed, 
could result in loss of M/R drive and subsequent loss of control of the 
helicopter.

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 Service Information

    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 
service information also contains the information specified in Appendix 
1 to this proposed AD, which specifies torque values, and Figure 1 to 
paragraph (g)(1) of this proposed AD, which depicts the areas for the 
flex plate inspection.

Proposed AD Requirements in This NPRM

    This proposed AD would require visually inspecting 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 the flex plate arms and depending on the inspection results, 
removing the flex plate from service and replacing it with an airworthy 
flex plate.
    This proposed AD would also require visually inspecting yoke P/N 
C907-1 or C907-2 as applicable, and yoke P/N C908-1, 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, this proposed AD would require visually inspecting each 
yoke bolt for a torque stripe, loose fastener, loose nut, and to 
determine if nut P/N D210-6 and palnut P/N B330-19 are installed. If 
there are any missing torque stripes, loose fasteners, loose nuts, or 
if nut P/N D210-6 or palnut P/N B330-19 are not installed, this 
proposed AD would require removing the associated yoke from service and 
replacing it with an airworthy yoke.
    This proposed AD would also require removing from service any yoke 
P/N C907-1 or C907-2 that has accumulated more than 12 years or 2,200 
total hours TIS, whichever occurs first since first installation on any 
helicopter, and replacing it with a yoke P/N C907-1 or C907-2 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, this proposed AD would 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, this 
proposed AD would 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 this proposed AD, this proposed AD would require torquing 
each bolt, nut, and palnut using the torque value information in 
Appendix 1 to this proposed AD.

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 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, 
would 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 would take approximately 6 work-hours and parts 
would 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 would take approximately 1.5 work-hours for an 
estimated cost of $128 per helicopter.
    Performing a magnetic particle inspection would take approximately 
1.5 work-hours for an estimated cost of $128 per helicopter.
    Applying torque to one bolt, nut, and palnut would take 
approximately 1 work-hour for an estimated cost of $85 per hardware 
set.
    If required, replacing a flex plate would take approximately 1 
work-hour and parts would 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

    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 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.

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:

[[Page 14598]]

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 adding the following new airworthiness 
directive:

Robinson Helicopter Company: Docket No. FAA-2024-0237; Project 
Identifier AD-2023-00491-R.

(a) Comments Due Date

    The FAA must receive comments on this airworthiness directive 
(AD) by April 15, 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, which includes the four bolt holes. 
If there is any loose fastener (can be moved by hand), crack, 
fretting, corrosion, or wear in any area including the four bolt 
holes, 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.

Figure 1 to Paragraph (g)(1)(i)--Flex Plate Inspection
[GRAPHIC] [TIFF OMITTED] TP28FE24.000

    (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 yoke bolt for a torque stripe, loose 
fastener, a loose nut, and to ensure that nut P/N D210-6 and palnut 
P/N B330-19 are installed. If there is a missing torque stripe, 
loose fastener on any nut (can be moved by hand), any nut is loose 
(nut can be turned by hand), or if nut P/N D210-6 or palnut P/N 
B330-19 are 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 helicopters on which a yoke replacement as specified in 
paragraphs (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) As an alternative to removing the yoke from service as 
required by paragraph (g)(2) of this AD, 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)(3)(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, missing cadmium plating,

[[Page 14599]]

and any flaw which is open to the surface. If there is any crack, 
seam, lap, shut, missing cadmium plating, 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)(3)(i) of this AD, visually 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: [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.

Appendix 1 to AD ####-##-##

[[Page 14600]]

[GRAPHIC] [TIFF OMITTED] TP28FE24.001


    Issued on February 21, 2024.
Victor Wicklund,
Deputy Director, Compliance & Airworthiness Division, Aircraft 
Certification Service.
[FR Doc. 2024-03970 Filed 2-27-24; 8:45 am]
BILLING CODE 4910-13-P