First flight of the Boeing 777X is likely to be delayed due to an engine issue

Seattle, Washington - Problems with the world's largest aircraft engine could force Boeing to delay the flight tests of the world's largest twin-engine jet.

During an industry event in New York, Boeing CFO Greg Smith said that some technical issues detected in the General Electric's GE9X engine could further delay the maiden flight of the Boeing 777X that was scheduled for June 26.

Smith reaffirmed that the problem wouldn't affect the aircraft's targeted delivery dates. The first copy will be delivered to the German flag carrier Lufthansa next year.

Delays are very common in a new aircraft program. Almost all popular jetliners that are in service today had program delays in the past. But, due to the ongoing 737 MAX crisis, such news from Boeing attract much attention.

"The long pole in the tent right now is the GE engine," Smith said. There are some challenges they are working through there on testing. So we are having to do some re-testing, and they're working their way through that," Smith said.

"As we see it today, we still expect to fly this year and enter into service in 2020, But obviously, we're staying very close to that and we'll keep you updated if that changes. But that's still the current assumption," the Boeing executive added.

The first two 777X prototypes have rolled out the final assembly line at the manufacturer's Everett factory for integrated system testing on the ground.

Two more aircraft are currently being assembled at the Boeing's Everett plant.

Boeing and the U.S. Federal Aviation Administration are both under close scrutiny by the federal government over aircraft certification after two deadly 737 MAX 8 crashes in less than six months.

For this reason, the process is unlikely to be accelerated to keep up with the previous schedule.