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.
(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.
ILLUSTRATION (Table 1 continued)
(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,
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: AMOC@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
(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: eric.r.moreland@faa.gov.
(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
ILLUSTRATION (Appendix 1)
