Airworthiness Directive · Amendment 39-13994 · Rolls-Royce plc Models RB211 Trent 768-60, Trent 772-60, and Trent 772B-60 Turbofan Engines
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 330 series airplanes.
The FAA is superseding an existing airworthiness directive (AD) for Rolls-Royce plc (RR) models RB211 Trent 768-60, Trent 772-60, and Trent 772-60 turbofan engines. That AD currently requires initial and repetitive surge margin testing of engines. This AD requires the same actions but at updated intervals. This AD also requires installation of updated software for the engine electronic controllers (EECs), and adds a terminating action for the surge margin testing requirement. This AD supersedure results from RR requiring EEC software to be revised, and extending the repetitive interval for surge margin testing for engines that have incorporated the software update for the EECs. This AD also results from RR introducing a stage 1 high pressure (HP) compressor casing and intermediate case outer location ring with wear-resistant coating, to reduce wear to prevent reduction in surge margin. We are issuing this AD to prevent a possible dual-engine in- flight surge, which could result in dual engine power loss.
You are responsible for having the actions required by this AD performed within the compliance times specified unless the actions have already been done.
Although RR Alert Service Bulletin (ASB) No. RB.211-71-AD509, Revision 3, dated October 17, 2003, allows surge margin testing of engines during revenue service, this AD only allows surge margin testing during dedicated maintenance checks.
Perform initial surge margin testing using paragraph 3 and Method A(1) of the Accomplishment Instructions of RR ASB No. RB.211-71-AD509, Revision 3, dated October 17, 2003, as follows:
(1) Before further flight, for engines that have accumulated more than 2,000 cycles-since-new (CSN) on the effective date of this AD; and for engines that have accumulated more than 1,000 cycles-since-overhaul (CSO) of the HP compressor casings and blades.
(2) Before accumulating 2,000 CSN for engines that have not had an overhaul of the HP compressor casing and blades.
(3) Before accumulating 1,000 CSO for engines that have had an overhaul of the HP compressor casings and blades.
Within 6 months from the effective date of this AD, install an EEC that features revised software to increase the in-flight N3 low idle schedule. Information on the revised software standard that features the increase in the in-flight N3 low idle schedule can be found in RR SB No. RB.211-73-AE224.
(i) For engines that do not have a revised EEC installed, as specified in paragraph (h) of this AD, perform repetitive surge margin testing at intervals not to exceed 130 cycles-since-last surge margin test. Use paragraph 3 and Method A(1) of the Accomplishment Instructions of RR ASB No. RB.211-71-AD509, Revision 3, dated October 17, 2003, for testing.
(j) For engines that do have a revised EEC installed, as specified in paragraph (h) of this AD, perform repetitive surge margin testing at intervals not to exceed 160 cycles-since-last surge margin test. Use paragraph 3 and Method A(1) of the Accomplishment Instructions of RR ASB No. RB.211-71-AD509, Revision 3, dated October 17, 2003, for testing.
Within 4,500 cycles-in-service after the effective date of this AD, install a stage 1 HP compressor casing and intermediate case outer location ring with wear-resistant coating. Use paragraph 3.A. of the Accomplishment Instructions of RR Service Bulletin No. RB.211-72-D574, Revision 1, dated January 12, 2004, to do this. Performing these actions is considered terminating action for the repetitive surge margin testing required by this AD.
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.
