Normally when an aircraft is rolled out of the hangar, it will do a test flight pilotted by Boeing test pilots. This is called a B1 flight. All going well, this is the only Boeing flown test flight the aircraft does. If there are any issues, they may do a B2
, or even B3
.....as many as it takes. When they are happy, it is handed over to the company's test crew (With Boeing supervision). This is called the C1. Any subsequent flights are C2
Ideally, an aircraft can get away with a B1 and a C1, and then be delivered. Each of these flights will be around 4 hours. B-HNM did up to a B3
, and up to a C2
before delivery.....so it was well work by the time we took it!