Rolls-Royce chief executive Warren East has acknowledged that premature blade deterioration on Trent 1000s continues to cause Boeing 787 operators "significant disruption" as aircraft are parked so that the engines can be serviced.
But he said during a financial results briefing today that the issues relating to compressor and turbine blades across different engine variants were now causing "an awful lot less disruption" than in the 2018.
The UK engine maker foresees that the number of aircraft on the ground will be reduced to a single-digit figure by year-end.
Earlier this year, R-R disclosed that blades in the high-pressure turbine of the Trent 1000 TEN – the latest variant of the engine family, an option on the 787 – deteriorate at a faster-than-expected rate, even though the component had already been subject to a reduced life limit of 1,000 cycles.
Some blades need replacement "a couple of hundred cycles" before reaching the 1,000 mark. East describes this as "completely unacceptable" in itself.
In April, the European Union Aviation Safety Agency directed operators to start repetitive inspections before the 650-cycle point and not to pair engines with more than 1,400 cycles combined.
R-R estimates that about a third of Trent 1000 TENs are affected by premature HPT blade deterioration.
East notes that the issue is creating additional pressure on overhaul facilities as the blades' replacement causes increased shop visit time. This in turn will extend "little bit longer" the time required to service earlier-generation Pack B and C Trent 1000s, he says.
R-R is in the process of testing a redesigned HPT blade for the Trent 1000 TEN.
Meanwhile, the manufacturer is progressing with the installation of a modified intermediate-pressure compressor blade for Pack C engines, which represent about half the Trent 1000 family's installed base.
As a number of Pack C engines operate with original IPC blades without issues, and don't need immediate replacement of the component, East foresees that the fleet-wide implementation of the new IPC blades will take "some time".
A redesign for the IPC blades for Pack B and TEN engines is meanwhile under way. East expects that the new IPC blade for the Trent 1000-TEN will become available for installation by year-end. The Pack B blade will follow "soon thereafter".
R-R says the Trent 1000 in-service issues brought a cash cost of £219 million ($268 million) in the first half of 2019, versus £107 million in the same period last year.
The cash cost will incrementally increase to a total of £450-500 million for the full year but then decrease by £50-100 million in 2020 and "materially thereafter", the manufacturer predicts.