Rolls-Royce chief executive Warren East is hopeful that the number of Boeing 787s grounded as a result of Trent 1000 issues can be cut from 35 today to 10 by year-end.

He notes that a number of Package C engines are now flying with a redesigned intermediate-pressure compressor blade certificated by the US Federal Aviation Administration and European Aviation Safety Agency in December 2018.

While most of the engines affected by the Trent 1000 durability issues are of the Package C variant, East says redesigned IPC blades for the Trent 1000-TEN and Package B are now in the approval process and should be certificated in the third and fourth quarter, respectively. Meanwhile, a hard-life limit for affected -TEN parts has been removed in favour of an inspection regime.

East acknowledges that R-R’s share of in-service and on-order 787s has declined in the wake of the Trent 1000 issues. Dreamliner operators have a choice between the Trent 1000 and GE Aviation's GEnx engine, and while R-R had hoped that the 787 orderbook would develop toward an equal split between the two engine suppliers, the UK manufacturer's share now stands at 35%, East says.

He acknowledges that several sales campaigns during the first half of 2018 "didn't go our way”, and says GE Aviation "utilised" the situation in a "very aggressive" manner. But he is sanguine about this: "Wouldn’t you?"

Despite the operational disruptions for affected airlines, East describes the Trent 1000 as a "very reliable” engine and says operators are able to "partition in their mind" between the powerplant's in-service performance and maintenance issues.

He expresses confidence that R-R can secure further Trent 1000 orders in future, and that the blade durability issues have been resolved.

The situation with the engine type was, East says, "very unusual" in that it involved multiple issues in the compressor and turbine sections, and several versions had entered service. In reference to the latest version, the -TEN, he says: "We are confident that we have solved the fundamental turbomachinery issues that caused all the hiatus in 2018."

Rolls-Royce has "thoroughly" tested its redesigned blades in a process "cross-examined" by Boeing, East points out. Meanwhile, airworthiness authorities were convinced "not only in terms of certification of the redesigned part, but very thorough analysis of the failure mechanism", he stresses.

"The best brains in the world on this [matter] have spent the last six months on this," says East. "That is confident as we can be."