Boeing’s new 777X aircraft will not fly until late autumn due to an issue with its GE9X engines.

At this week’s Paris Air Show, head of commercial jet engines at GE Aviation Bill Fitzgerald said engineers have a fix, but extensive testing is required before it can be applied to the eight engines already delivered to Boeing.

GE will “be in a position to complete the testing by the end of the year and have the plane fly by the end of the year,” Fitzgerald said.

The first 777x was showcased to Boeing employees at the manufacturer’s Seattle HQ in March.

A planned press event was cancelled due to the crash earlier in the month of an Ethiopian Airlines flight operated by Boeing’s 737 Max, which led to the worldwide grounding of the aircraft.

The president of Emirates, which is set to receive the 777X next summer, told the Seattle Times last week that he was initially told the first flight had been pushed back from March to June, and then that he hoped it would fly before mid-July.

At the Paris Air Show this week, Boeing and International Airlines Group held a deferred ceremonial signing to celebrate its order for 18 777X aircraft. It has options for 24 more.

The wide-body aircraft will have two variants, the 777-8 and the 777-9. The GE engines are touted as being the most fuel-efficient ever used on a commercial aircraft.

The plane also features folding wingtips that allow an optimised wingspan while still allowing use of existing airport gates.

Its customers also include ANA, Cathay Pacific, Etihad, Lufthansa, Qatar Airways and Singapore Airlines.

Boeing currently refers to Lufthansa as “a launch customer” of the aircraft.

In January Boeing released pictures of the B777X interiors, which are based on its Dreamliner cabins:

Boeing offers glimpse of B777-X interiors