2024-19-11: Engine/Transmission coupling

1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. 2. The FAA amends § 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 ER26SE24.000 (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 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: 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) 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: Eric.R.Moreland@faa.gov . (k) Material Incorporated by Reference None. Appendix 1 to AD 2024-19-11 BILLING CODE 4910-13-P ER26SE24.001 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-P