GUY NORRIS / LOS ANGELES
Manufacturer plans two-phase upgrade to tackle powerplant performance deterioration in hot and heavy conditions
An upgrade package to tackle faster than expected performance deterioration on Rolls-Royce Trent 800s operating in hot and heavy conditions is expected to be shipped to Boeing 777 operators by year-end.
The upgrade, designated the 895C, comes in two main phases, the first part of which is already being retrofitted during maintenance downtimes. The initial upgrade consists of improved high pressure (HP) and intermediate pressure (IP) turbine seal segments which have been revised with improved cooling and materials resistant to higher temperatures. The more resilient material is being used in the abradable honeycomb of the seal and the solid backplate supporting it. The latter is now made using "a single crystal style of material", says Trent 800 chief engineer Andy Geer.
The second part of the upgrade consists of an enhanced cooling and thermal barrier coating (TBC) treatment for the IPT and HPT nozzle guide-vanes. The TBC material, already used in the Trent 500, covers the guide-vane platform. and is being extended to cover the vane, adds Geer. "Hardware will be delivered at the end of the year in new engines, as well as being available for retrofit," he says.
The improvements counter "more rapid thermal deterioration than expected" on higher-power Trent 895s, particularly on 777-300s flown by Dubai-based Emirates, which is expected to be a key beneficiary of the 895C package (Flight International, 19-25 November). Geer says that time-on-wing is expected to improve by "at least 25%" as a result of the changes.
R-R, meanwhile, says inspections of the suspect 892 engine operated by Thai, which was shut down on approach to Taipei on 11 November, has shown the problem was "maintenance-related".
Although the engine-maker declines to detail the cause, it is believed to have to do with detachment of part of the recently overhauled annulus.
Source: Flight International
