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.

Proposed Rules Federal Register

14596 

Vol. 89, No. 40 

Wednesday, February 28, 2024 

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). 

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 partnumbered 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 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: Eric.R.Moreland@faa.gov. 

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: 

Eric.R.Moreland@faa.gov. 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 


ddrumheller on DSK120RN23PROD with PROPOSALS1
Federal Register / Vol. 89, No. 40 / Wednesday, February 28, 2024 / Proposed Rules 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: 


ddrumheller on DSK120RN23PROD with PROPOSALS1
14598 Federal Register / Vol. 89, No. 40 / Wednesday, February 28, 2024 / Proposed Rules 

PART 39—AIRWORTHINESS 

DIRECTIVES 

■ 1. The authority citation for part 39 

continues to read as follows: 

Authority: 49 U.S.C. 106(g), 40113, 44701. 

§ 39.13 [Amended] 

■ 2. The FAA amends § 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 

(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 newlyinstalled 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, 


ddrumheller on DSK120RN23PROD with PROPOSALS1EP28FE24.000</GPH>

Give special attention to 

these areas for cracks 

Inspect entire periphery for 

cracks and corrosion. 

Inspect this area for cracks. 

Inspect area around washers 

for fretting. 
Federal Register / Vol. 89, No. 40 / Wednesday, February 28, 2024 / Proposed Rules 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 FAAapproved 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: 9-ANMLAACO-AMOC-REQUESTS@faa.gov. 

(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: Eric.R.Moreland@faa.gov. 

(k) Material Incorporated by Reference 

None. 

Appendix 1 to AD ####–##–## 


ddrumheller on DSK120RN23PROD with PROPOSALS1
14600 Federal Register / Vol. 89, No. 40 / Wednesday, February 28, 2024 / Proposed Rules 

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 


ddrumheller on DSK120RN23PROD with PROPOSALS1EP28FE24.001</GPH>

NOTE 

1. Torque values .-,e ln lneh-poum:1, unle• otherwl• spiaeltled. 

2. Torqt.11;11 \i'~ llncludG nut QIN~ tt!V~. 

3. ltlCQ(IIN! torque velU8$ 1 O'IJEi If to~d 8t bolt head. 

4. W•t indle.-:es ~ lll,ilbr,lc.ted with .A257•9 Inti-~. 

5. For elbow and tee fit.tings which require atlgn~. torque to lnd~ 

vak,1111, thiut tighten t{)I d••hd pi,Mi,ition. 

6. Tolerance 1$ ± 1 O'IJEi. min$ fllnQG l$ s~. 

7. Unle$$ a,tl,erwlN spadflad,. thread SIU$ &-32 and llfflllktr ~ n()t -.ed k)r 

Pftm&f'Y ,tructunt and do not nitqulre eon~ Qt t:orQ1,i19$. 

10-32 NAS8803 

NAS6603 th11,.1 NAS8608 Bolts 114~28 NAS8804 

NAS 1303 th11,.1 NAS 1 308 :Bolts 5116-24 NAS8805 NAS823 ScreW$ 318-24 NA.$8608 NAS1351 & NAS1352 SCntW$ 

NAS6001bru NASOOG Screws 7116-20 NAS6607 

112~20 NAS8808 

At 42 $CQW$ AN502 se,-W$ 10-32 A142•1, ·3, -4; AN3 

AN503 Seri!IW:$ AN3 Boll$ AN509 ScriilW:$ 1/4,-28 AN4 

AN4~ 

AN8~ AN525 SeraW:$ 318•24 AN8 . M:824694 Setews AN8Bolt$ : MS27039 Setews 112·20 ANS 

10-32 8330..7 CMS.27151•7l 

STAMPED NUTS 114-21 8330-13 CMS27151•t3l 

{fl'ALNUTS) 5116-24 8330-16 CMS27151·161 

Painutt; are to be uNd ol'llv ·~ 318-24 8330-19 tMS27151·19l .-nd ntpllf;l!l.!id with ne-w when 

rf)lfflOV8d. 7116-20 8330-21 CMS27151~21 l 

112~20 8330-24 IMS27151•2•4l 

118-27 5" note 5 

Str1,1ight flttlngg onty 

1/4,-18 S..note 5 

Str•lght fittings onty 

TAPEAED PIPE 3/&-18 S..note 5 

THREADS Str1,1lght fittings onty 

112~14 S..note 5 

Str.alght Httlngg Qnly 

314*14 See note 5 

Straight fittings onty 

10-32 AN315-3 

ROD END JAM MJ'l'S 114-28 AN31M 

(AN315 ~ AN316} 5116-24 AN316-5 

318-24 AN318-6 

50 

120 

240 

350 

665 

995 

37 

90 

28() 

'195 

6-15 

11-25 

20-40 

29-80 

42-85 

54-110 

50 

120 

85 

170 

110 

220 

180 

320 

230 

480 

15 

40 

80 

110