There's no need to have any false illusions here - nothing will happen before 2029/30 with a prototype engine. Don't expect the first production Serial aircraft with their own functioning engine until 2032/33.
The validation and testing of a high-performance engine takes at least 3-4 years and an additional 1-2 years for flight tests.
I am sure that Block 0 and maybe 10 will still run with F119 engines.
The validation and testing of a high-performance engine takes at least 3-4 years and an additional 1-2 years for flight tests.
I am sure that Block 0 and maybe 10 will still run with F119 engines.