Airworthiness Directive · Amendment 39-19023 · Turbine section
Rolls-Royce Corporation Turboshaft Engines
Superseded. A later AD replaced this one: AD 2022-10-06. Comply with the one in force.
This AD applies to Rolls-Royce Corporation (RRC) 250-C20, -C20B, -C20F, -C20J, -C20R, -C20R/1, -C20R/2, -C20R/4, -C20W, -C300/A1, and -C300/B1 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.
We are superseding Airworthiness Directive (AD) 2015-02-22 for certain Rolls-Royce Corporation (RRC) model 250 turboprop and turboshaft engines. AD 2015-02-22 required repetitive visual inspections and fluorescent-penetrant inspection (FPIs) on certain 3rd- stage and 4th-stage turbine wheels for cracks in the turbine wheel blades. This AD requires repetitive visual inspections and FPIs of 3rd- stage turbine wheels while removing from service 4th-stage turbine wheels. We are also revising the applicability to remove all RRC turboprop engines and add additional turboshaft engines. This AD was prompted by our finding that it is necessary to remove the 4th-stage wheels at the next inspection. We are 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 before the next flight after the effective date of this AD, whichever occurs later:
(i) Remove 3rd-stage turbine wheels, P/N 23065818, and perform a visual inspection and an FPI on the removed turbine wheels for cracks at the trailing edge of the turbine blades, near the fillet at the rim.
(ii) Thereafter, re-inspect the affected turbine wheels every 1,775 hours since last inspection (HSLI).
(2) Any time the turbine is disassembled, perform a visual inspection and an FPI on 3rd-stage turbine wheels, P/N 23065818, for cracks at the trailing edge of the turbine blades, near the fillet at the rim.
(3) Do not return to service any turbine wheels found to have cracks at the trailing edge, near the fillet at the rim, of the turbine blades.
(4) Within 1,775 HSLI, or at the next engine shop visit, whichever occurs later, remove 4th-stage turbine wheels, P/N 23055944, from service.
(5) Within 2,025 HSLI, or at the next engine shop visit, whichever occurs later, remove 4th-stage turbine wheels, P/N RR30000240, from service.
For the purpose of this AD, an “engine shop visit” is the induction of an engine into the shop for maintenance involving the 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.
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
