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

GE Aerospace showed off its Boeing 747 "flying laboratory" in July. It's being used to test the engine of Boeing's future 777X. Carl Court/Getty Images GE Aerospace uses a decades-old Boeing 747 to test and help certify new commercial jet engines. The aircraft is filled with cabling, metal data boxes, workstations, and passenger recliners. Business Insider toured the unique 747 at an airshow in July and spoke with GE's chief test pilot. Leading American manufacturer GE Aerospace is building the world's largest jet engine for Boeing's coming 777X — and it needs a massive plane to test it. The enginemaker bought a now-32-year-old Boeing 747-400 from Japan Airlines in 2010 to serve as its modern Flying Test Bed, or FTB. It replaced the aging Boeing 747-100 that GE had had since 1992.