The flight tests are complete, the paperwork submitted, and certification of the Falcon 6X, Dassault Aviation’s flagship-in-waiting, is expected “in the coming weeks,” CEO Éric Trappier said this week at EBACE. But the twinjet's journey to service entry began well before its first test flight in February 2021, as Philippe Duchateau, chief test pilot on the program, explained aboard the outfitted 6X on the EBACE static display (AD_02) in Geneva.
The test program begins “in the development phase, with a lot of work on the ground before even getting to the flight line,” said Duchateau. Flight-test pilots first meet with engineers to “discuss what the aircraft should be like” in terms of flight control response, handling, and cockpit ergonomics. Engineers then create a basic simulator to mimic the desired characteristics and “we go and test it” to refine the controls, said Duchateau, a former French Air Force test pilot.
“Once your system is optimized, you test it with real [flight control] boxes,” he said. “That allows us to have the best preview of the handling qualities and flying qualities of aircraft.”
When the resulting system is integrated into the prototype aircraft, the flight tests begin. Each test flight is carefully planned and may first be "flown" in the simulator multiple times in preparation.
“When you do the envelope extension [flights], or the dive to [Mach] 0.97 [performed to achieve certification for the 6X’s Mach 0.925 top speed], you repeat it many times on the bench before doing it for real,” he said.
Each test flight is followed by an extensive debriefing. “Then it's time to write reports,” detailing any issues discovered, Duchateau said. “When you go to the test pilot school, you learn how to fly, but also how to write those reports.”
The test regime also aims to identify human factors that can impact pilot performance. On some flights pilots wear video goggles so engineers who monitor the test flights in real-time can see where pilots are looking and where their hands move to ensure the flight deck layout is intuitive and easy to interact with. In addition, the test program is designed to uncover ways less experienced pilots could encounter difficulties flying the jet.
“As test pilots, we have got to forget about the egos. We don't want to be top pilots, we just want to understand what could go wrong, what could be misleading,” Duchateau said. “You have to put yourself in the situation of a youngster getting on the aircraft and try to make his life easier. That is the real job for a test pilot.”
The 6X certification program used four test aircraft, accumulating a total of some 1,700 flight hours over about 600 flights — figures in line with initial projections. The final phase of the program, called Mission 1, took the aircraft “all over the world,” flying typical flight profiles, with a variety of pilots at the controls, logging some 200 hours over more than 90 flights.
When certification comes, “We'll have a glass of champagne, but it's not the end of the story,” Duchateau said. “We still have the steep approach [certification] to go, and we’ll extend the crosswind limitation. We'll try to push the envelope everywhere that we can. So it's not finished yet.”