We toured a specially modified Boeing 747 used as a ‘flying laboratory’ to test new jet engines. See inside.

GE Aerospace is building the world's largest jet engine for Boeing's new 777X, and it's using a giant 747 to test it. We toured the unique plane. GE Aerospace is building the world's largest jet engine for Boeing's new 777X, and it's using a giant 747 to test it. We toured the unique plane.