Airworthiness Directive · Amendment 39-17120 · Rolls-Royce Corporation Turboshaft Engines
Rolls-Royce Corporation Turboshaft Engines
Superseded. A later AD replaced this one: AD 2015-02-22. Comply with the one in force.
This AD applies only to Rolls-Royce Corporation 250-C20, -C20B, and -C20R/2 turboshaft engines with 3rd stage turbine wheel, part number (P/N) 23065818, and 4th stage turbine wheel, P/N 23055944.
We are adopting a new airworthiness directive (AD) for certain Rolls-Royce Corporation (RRC) 250-C20, -C20B, and -C20R/2 turboshaft engines. This AD was prompted by seven cases reported of released turbine blades and shrouds, which led to loss of power and engine in- flight shutdowns (IFSDs). This AD requires a one-time visual inspection and fluorescent penetrant inspection (FPI) on certain 3rd and 4th stage turbine wheels for cracks in the turbine blades. We are issuing this AD to prevent failure of 3rd or 4th stage turbine wheel blades which could cause engine failure and damage to the airplane.
(1) Remove the 3rd stage turbine wheel, P/N 23065818, and the 4th stage turbine wheel, P/N 23055944, within 1,750-hours since last inspection.
(2) Perform a one-time visual inspection and a fluorescent penetrant inspection on the 3rd and 4th stage turbine wheels for cracks at the trailing edge of the turbine blades near the fillet at the rim.
(3) If any cracks in the trailing edge near the rim are detected, do not return the wheel to service.
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
