AD 2025-11-07 Airworthiness Directives; Robinson Helicopter Company Helicopters

Makes named: robinson. Models named: R44, R44 II. Read the applicability below — it usually turns on serial or part numbers too.

This AD applies to Robinson Helicopter Company Model R44 and R44 II helicopters, certificated in any category.

Comply with this AD within the compliance times specified, unless already done.

(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. EN06JN25.000 (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 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 Prior to accumulating 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, 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 having serial number 30001 and subsequent Prior to accumulating 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, 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, 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.

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.

This AD replaces AD 2024-19-11, Amendment 39-22853 (89 FR 78785, September 26, 2024).