Airworthiness Directive · Amendment 39-14776 · Rolls-Royce Corporation Models 250-C30, 250-C40, and 250-C47 Series Turboshaft Engines
Rolls-Royce Corporation Models 250-C30, 250-C40, and 250-C47 Series Turboshaft Engines
This AD applies to Rolls-Royce Corporation (RRC) models 250-C30, -C30G, -C30G/2, -C30M, -C30P, -C30R, -C30R/1, -C30R/3, -C30R/3M, -C30S, -C30U, -C40B, -C47B, and -C47M turboshaft engines, with a third-stage turbine wheel, part number (P/N) 6898663 or P/N 23065843 installed, or a fourth-stage turbine wheel, P/N 6892764 or P/N 23066744, installed. These engines are installed on, but not limited to, Bell 206L-3, Bell 206L-4, Bell 230, Bell 407, Bell 430, MDHI 369F, MDHI 369FF, MDHI 600N, and Sikorsky S-76A helicopters.
The FAA is adopting a new airworthiness directive (AD) for Rolls-Royce Corporation (RRC) models 250-C30, 250-40, and 250-C47 series turboshaft engines with a third-stage turbine wheel, part number (P/N) 6898663 or P/N 23065843 installed, or a fourth-stage turbine wheel, P/N 6892764 or P/N 23066744, installed. This AD adds an additional life limit for third- and fourth-stage turbine wheels. This AD results from analysis by RRC of failures of third-stage turbine wheels. We are issuing this AD to prevent loss of power, possible engine shutdown, or uncontained engine failure.
You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.
(f) Within 30 days after the effective date of this AD, record each time the third- and fourth-stage turbine wheels enter into the speed range between “Event Threshold” and “Maximum Overspeed Transient”. Use paragraph 2.A. through 2.A.(5) of the Accomplishment Instructions and the applicable Figures 1 through 5 of RRC Alert Commercial Engine Bulletins (CEBs) No. CEB A-72-3272, No. CEB A-72-5048, and No. CEB A-72-6054 (combined in one document), all Revision 2, dated June 27, 2006, to determine the speed range.
(g) Remove and retire any third-stage turbine wheel or fourth-stage turbine wheel after the sixth time the wheel enters into the speed range between “Event Threshold” and “Maximum Overspeed Transient”.
The retirement criteria in this AD are in addition to the existing third- and fourth-stage turbine wheel hour and cycle life limits. You must retire the wheels when you exceed any published life limit (transient speed excursions, hours, or cycles).
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Engines
