AD 2006-05-03 Airworthiness Directives; Rolls-Royce plc Models RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 Turbofan Engines

This AD applies to Rolls-Royce plc (RR) models RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 turbofan engines. These engines are installed on, but not limited to, Airbus A330-243, A330-341, A330-342, and A330-343 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 Borescope Inspection (f) Perform an initial borescope inspection of the HP-IP turbine bearing internal oil vent and scavenge tubes and tube heat shields before the thresholds listed in Table 1 of this AD, or within 4 months after the effective date of this AD, whichever occurs later. To do the inspections, use either the on-wing or the in-shop inspection procedures in the Accomplishment Instructions of RR Alert Service Bulletin (ASB) RB.211-72-AE792, dated July 8, 2005. Table 1.—Inspection Criteria Action Inspection threshold (1) Initial inspection 10,000 hours time-since-new (TSN) or time-since-overhaul (TSO), or 2,500 cycles-since-new (CSN) or cycles-since-overhaul (CSO), whichever occurs first. (2) Repetitive inspection interval for tubes with no visible damage to outer heat shields on the tubes 10,000 hours time-since-last-inspection (TSLI), or 2,500 cycles-since-last-inspection (CSLI), whichever occurs first. (3) Repetitive inspection interval for tubes with cracking up to 90 degrees around tube circumference or 10 millimeters along the length of either outer heat shield 6,400 hours TSLI or 1,600 CSLI, whichever occurs first. (4) Repetitive inspection interval for tubes with cracking greater than (3) above, but less than 360 degrees around the tube circumference 1,600 hours TSLI or 400 CSLI, whichever occurs first. Repetitive Borescope Inspections (g) Repeat the borescope inspections of the HP-IP turbine bearing internal oil vent and scavenge tubes within the applicable intervals listed in Table 1 of this AD. To do the inspections, use either the on-wing or the in-shop inspection procedures in the Accomplishment Instructions of RR ASB RB.211-72-AE792, dated July 8, 2005. Removal of Damaged Tubes (h) Within 10 CSLI, remove tubes with cracking around the complete circumference of either outer heat shield, or if any material is missing from either outer heat shield, or if either tube is fretted by loose heat shield material. Terminating Action (i) As terminating action to the repetitive inspections required by paragraph (g) of this AD, at the next IP (05) module overhaul, but before May 31, 2010, remove the HP-IP bearings supports introduced prior to Rolls-Royce Modification 72-E708 and replace with serviceable parts. Information on Rolls-Royce Modification 72-E708 can be found in RR Service Bulletin RB.211-72-E708, Revision 2, dated September 6, 2005. Definition (j) For the purposes of this AD, serviceable parts are new or reworked bearings supports which reduce the adverse effects of HP3 cooling air turbulence on the HP-IP turbine bearing internal oil vent and scavenge tubes and tube heat shields, as described in Rolls-Royce Modification 72-E708. Alternative Methods of

This AD results from two reports of RR RB211 Trent 700 series engines found with the high pressure-intermediate pressure (HP-IP) internal oil vent tube and scavenge tube fretted by damaged heat shields on the tubes. Burning oil can cause the intermediate pressure (IP) shaft to fracture, the IP turbine to overspeed, and possible uncontained failure of the engine. We are issuing this AD to prevent oil ejecting from the HP-IP turbine bearings chamber and igniting.