Boeing has stationed the fourth 787 Dreamliner, ZA004, in Colorado Springs for a series of high-field-elevation tests over several days.
The tests, to be carried out an airport with a high elevation, follow tests on the same aircraft in Mesa, Arizona, conducted at a low-elevation airport in hot weather, says Boeing.
"Earlier this month another 787 conducted touch-and-go manoeuvres in Colorado Springs," it adds.
The 787 flight test fleet, comprising four aircraft, has logged more than 840 hours of flying in the last six months. Two more aircraft will join the fleet soon, says Boeing.