Airworthiness Directive · Amendment 39-22044 · Turbine section
Rolls-Royce Corporation Turboshaft Engines
This AD applies to Rolls-Royce Corporation (RRC) 250-C20, 250-C20B, 250-C20C (T63-A-720), 250-C20F, 250-C20J, 250-C20R, 250-C20R/1, 250-C20R/2, 250-C20R/4, 250-C20W, 250-C300/A1, and 250-C300/B1 model turboshaft engines with either a 3rd-stage turbine wheel, part number (P/N) 23065818, or a 4th-stage turbine wheel, P/N 23055944 or RR30000240, installed.
The FAA is superseding Airworthiness Directive (AD) 2017-18- 14, which applied to certain Rolls-Royce Corporation (RRC) 250 model turboshaft engines. AD 2017-18-14 required repetitive visual inspections and fluorescent penetrant inspections (FPIs) of the 3rd- stage turbine wheel and removal from service of the 4th-stage turbine wheel. This AD was prompted by in-service turbine blade failures that resulted in the loss of power and engine in-flight shutdowns. This AD requires replacement of the 3rd-stage and 4th-stage turbine wheels. This AD also revises the applicability to include an additional turboshaft engine model. The FAA is issuing this AD to address the unsafe condition on these products.
(1) Within 1,775 hours since last visual inspection and fluorescent penetrant inspection (FPI), or at the next engine shop visit, whichever occurs first after the effective date of this AD, remove:
(i) 3rd-stage turbine wheel, P/N 23065818, and replace with a part eligible for installation.
(ii) 4th-stage turbine wheel, P/N 23055944, and replace with a part eligible for installation.
(2) Within 2,025 hours since last visual inspection and FPI, or at the next engine shop visit, whichever occurs first after the effective date of this AD, remove 4th-stage turbine wheel, P/N RR30000240, and replace with a part eligible for installation.
(1) For this purpose of this AD, an “engine shop visit” is the induction of an engine into the shop for maintenance in which the turbine module is separated from the exhaust collector, the gas-producer-support is separated from the power-turbine-support, or there is separation of pairs of major mating engine flanges, except that the separation of engine flanges solely for the purposes of transportation without subsequent engine maintenance does not constitute an engine shop visit.
(2) For the purpose of this AD, a “part eligible for installation” is a 3rd-stage turbine wheel or 4th-stage turbine wheel that does not have a P/N listed in the Applicability, paragraph (c), of this AD.
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.
