Airworthiness Directive · Amendment 39-17376 · Rolls-Royce plc Turbofan Engines
Rolls-Royce plc Turbofan Engines
This AD applies to Rolls-Royce plc (RR) RB211-Trent 970-84, RB211-Trent 970B-84, RB211-Trent 972-84, RB211-Trent 972B-84, RB211-Trent 977-84, RB211-Trent 977B-84, and RB211-Trent 980-84 turbofan engines that incorporate RR production Modification 72-G585 or modified in-service through RR Service Bulletin (SB) 72-G585, any revision, with a Module 33 installed having a serial number (S/N) prior to HC0320, except S/Ns HC0277, HC0281, HC0294, HC0301, HC0309, HC0313, HC0315, and HC0318.
We are adopting a new airworthiness directive (AD) for certain Rolls-Royce plc (RR) RB211-Trent 970-84, RB211-Trent 970B-84, RB211- Trent 972-84, RB211-Trent 972B-84, RB211-Trent 977-84, RB211-Trent 977B-84, and RB211-Trent 980-84 turbofan engines. This AD requires inspection of the intermediate pressure compressor rear stub shaft (IPC RSS) piston ring. This AD was prompted by the failure of an oil pump drive shear neck due to a piston ring seal that was not seated properly in the IPC RSS groove. We are issuing this AD to prevent failure of the oil pump drive shear neck, which could result in loss of oil pressure in one or more engines and reduced control of the airplane.
Unless already done, do the following.
(1) Within 50 engine flight cycles after the effective date of this AD, inspect the IPC RSS piston ring in accordance with the instructions of paragraph (d)(2) of RR Repeater Technical Variance 129978, Issue 2, dated December 20, 2012.
(2) For an engine that is not in service on the effective date of this AD, before returning the engine to service, inspect the IPC RSS piston ring on-wing in accordance with paragraph (d)(2) of RR Repeater Technical Variance 129978, Issue 2, dated December 20, 2012; or in shop using paragraph (d) of RR Repeater Technical Variance 129994, Issue 1, dated December 19, 2012.
(3) If, during the inspections required by paragraph (e) of this AD, you find that the piston ring seal is not seated properly in the IPC RSS groove or is not intact, replace the piston ring seal or piston ring assembly before returning the engine 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
