AD 2004-23-03 Airworthiness Directives; Rolls-Royce plc RB211 Trent 700 Series Turbofan Engines

This AD applies to Rolls-Royce plc (RR) RB211 Trent 768-60, RB211 Trent 772-60, and RB211 Trent 772B-60 series turbofan engines. These engines are installed on, but not limited to, Airbus A330-243, -341, -342 and -343 series airplanes.

You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done. Initial Visual Inspection (f) Using the inspection schedule in Table 1 of this AD, perform an initial borescope inspection of the high pressure-and-intermediate pressure (HP-IP) turbine internal and external oil vent tubes for coking and carbon buildup as follows: (1) Insert an 8 mm diameter flex borescope to see if it will pass along the full length of the vent tube into the bearing chamber. (2) If the vent tube prevents an 8 mm diameter flex borescope from passing along the full length of the tube into the bearing chamber, repeat the action using a 6mm flex borescope. (3) If the 6 mm diameter flex borescope passes through to the bearing chamber, continue using the engine in service, and perform the repetitive inspections in this AD at the required intervals. (4) If the vent tube prevents the 6 mm diameter flex borescope from passing along the full length of the tube into the bearing chamber, clean or replace the vent tube. Information on oil vent tube cleaning or replacement can be found in Rolls-Royce plc Alert Service Bulletin No. RB.211-72-AE302, Revision 1, dated May 25, 2004. Table 1.—Initial Inspection Schedule If the engine or the 05 module: Then initially inspect: Has reached 10,000 hours time-since-new (TSN) or reached 2,500 cycles-since-new (CSN) on the effective date of this AD Within 3 months after the effective date of this AD. Has fewer than 10,000 hours TSN or fewer than 2,500 CSN on the effective date of this AD Within 3 months after reaching 10,000 hours TSN or 2,500 CSN, whichever occurs first. Repetitive Visual Inspections (g) Using the inspection schedule in Table 2 of this AD and paragraphs (f)(1) through (f)(4) of this AD, perform repetitive borescope inspections of the HP-IP turbine internal and external oil vent tubes for coking and carbon buildup. Table 2.—Repetitive Inspection Schedule If at the previous inspection, before any cleaning was performed: Then: (1) There was no coking and carbon buildup of a visible thickness; or an 8 mm diameter flex borescope could pass along the full length of the internal vent tube into the bearing chamber Reinspect within 6,400 hours time-since-last-inspection (TSLI) or within 1,600 cycles-since-last-inspection (CSLI), whichever occurs first. (2) The coking or carbon buildup prevented an 8 mm diameter flex borescope from passing through the internal vent tube, but a 6 mm diameter flex borescope could pass along the full length of the internal vent tube into the bearing chamber Reinspect within 1,600 hours TSLI or within 400 CSLI, whichever occurs first. (3) The coking or carbon buildup prevented the 6 mm diameter flex borescope from passing through the full length of the internal vent tube and into the bearing chamber Clean or replace the vent tubes within 10 CSLI. Information on oil vent tube cleaning or replacement can be found in Rolls-Royce plc Alert Service Bulletin No. RB.211-72-AE302, Revision 1, dated May 25, 2004. Alternative Methods of

This AD results from a report of a RB211 Trent 700 series engine experiencing a disk shaft separation, overspeed of the IP turbine rotor, and multiple blade release of IP turbine blades. Preliminary findings suggest these events resulted from an internal oil fire in the HP-IP turbine oil vent tubes due to coking and carbon buildup. This fire led to a second fire in the internal air cavity below the IP turbine disk drive shaft. We are issuing this AD to prevent internal oil fires due to coking and carbon buildup, that could cause uncontained engine failure and damage to the airplane.