Summary Boeing's 777X testing program involves four planes with distinct roles for certification and ongoing test flights. Certification testing for the 777X includes various steps to collect information needed for FAA approval. The third prototype aircraft, N779XY, will do the majority of certification flights with the FAA.

US aircraft manufacturer Boeing's testing program for its upcoming 777X flagship widebody is well underway. The manufacturer has completed four test aircraft, each with a different role in the certification process and set of test equipment. The planes are registered to highlight the 777-9X designation uniquely and are given sequential final letters corresponding to the last letters of the alphabet.

Collectively, they have completed over 3,500 hours of flight tests across 1,200 sorties in preparation for FAA certification, which began last month . Airplane One: N779XW The very first 777X aircraft to roll out was anointed with the manufacture serial number 64240 and the unique registration of N779XW. All four models are of the Boeing 777-9 designation, with the smaller 777-8 to follow at a later date.

Simple Flying was on hand for the first flight of a 777X test plane, which occurred on January 25th, 2020 Since its first flight, the aircraft has continued to conduct test flights for the manufacturer and was most recently spotted conducting flights between one and five hours out of Boeing Everett Paine Field. The aircraft is equipped with a water ballast sy.