Safran has admitted that it needs a second customer for its Silvercrest engine to justify its expenditure on the programme.

Speaking on a third-quarter results call on 23 October, chief financial officer Bernard Delpit said: "One application is not enough for the amount of investment we have made in this engine."

So far, the sole application for the Silvercrest is on the Cessna Citation Hemisphere. The turbofan had also been selected by Dassault to power the 5X, but delays to the engine caused the entire programme to be axed.

Delpit says conversations with prospective customers are ongoing and Safran is "still optimistic" about the engine's future.

Scott Donnelly, chief executive of Cessna parent Textron, says it expects to have a firm idea by mid-2019 as to whether Safran has solved the compressor issue that has plagued the Silvercrest.

"I think that the issue is very, very well understood. They believe the design solution and the model they've come up with addresses that, which is terrific," he said on 18 October.

"That being said, we do want to see it on the test bench. So I think you're looking at a mid-year next year when we would say 'okay, this is a firm goer or not'."

Textron and launch customer NetJets, which has ordered 150 examples, will continue to invest in order to be ready to "pull the trigger" once Safran has validated the engine's performance.