Thierry Dubois is a freelance writer specializing in helicopters, business aviation and aerospace technology. He earned a degree in fluid dynamics from an engineering school in Toulouse, France in the mid-1990s. At an unexpected crossroads, he found his first job in journalism. In 1997, he started working for French aerospace weekly Air &amp; Cosmos in Paris. This lasted until 2000, when he moved south to Lyons. He then became a freelancer, working for various aerospace publications and has been part of the AIN team since late 2000. In addition to writing about business aviation, Thierry shares responsibility for the rotorcraft section. He also is a regular on-site writer for AIN’s daily editions at international airshows such as the Paris, Farnborough, Dubai and Singapore shows, as well as at EBACE in Geneva.
In 2007, he won the Honeywell award for “Best systems or technology submission” at the Aerospace journalist of the year awards. In 2013, he won an Aerospace Media Award for the "Best Safety, Training &amp; Simulation Submission."
In other activities, Thierry moderates international conferences on aviation technology topics. Thierry is married and has three children, who seem to begin enjoying the mountains–as their parents do.

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Thierry Dubois

Dassault is preparing to fly two new Falcons–the Falcon 5X twinjet and the Falcon 8X trijet, both large-cabin business aircraft–in the first half of 2015. Five test aircraft are thus expected to grace Dassault’s Istres, France ramp by the end of next year. The 5,200-nm Falcon 5X was announced at the 2013 NBAA show and the 6,450-nm Falcon 8X a few months later at EBACE 2014.
As the Falcon 8X is a derivative of the in-service Falcon 7X, its development is moving faster and it is slated to fly in the first quarter of next year. The first test aircraft has been put together; its electrical systems were powered up in July and the first engine run is scheduled for November. In mid-October, it was about to complete ground vibration tests at Dassault's Bordeaux Mérignac factory. About 500 vibration inducers were generating various frequencies. During a recent visit to that facility, AIN also could see the dedicated spike for the test pitot tube installed at the tip of the nose cone.
This first aircraft will be dedicated to flight envelope expansion, said chief test pilot Philippe Deleume. The second Falcon 8X, scheduled to fly in the second quarter of 2015, will focus on performance. A third example, while not a test aircraft, will help with cabin systems and preparation for entry into service.
The Falcon 8X campaign will total 550 flight hours in 200 flights and 14 months, according to Dassault’s plan. Some 700 analog parameters will be followed, which is fewer than for the Falcon 5X. “We already have some information from the 7X, and test equipment is complex and heavy,” Deleume explained.
Falcon 8X certification is planned for mid-2016 and initial deliveries in the second half of that year. Dispatch reliability at entry into service is targeted at 99.97 percent.
Also at the Bordeaux Mérignac factory, the airframer is close to completing the final assembly of the first Falcon 5X. The first test of the fuel system was performed in September and the first engine run is planned for December or early January. This means the ground-test schedule has slipped slightly to the right. Nevertheless, Dassault is confident that the first flight will take place in the second quarter of 2015.
Snecma crews have been flying the Silvercrest engine on a modified Gulfstream G2 (see story page 40). Dassault also plans for some pilots to fly the Gulfstream to “have a feeling of the engine,” Deleume told AIN. The 5X airframe built for static and fatigue trials has arrived at the CEAT test facility in Toulouse, where actual testing is to begin in December.
At its Saint-Cloud headquarters, near Paris, Dassault engineers are making an intensive use of the “Falcon simulation bench.” In addition to fly-by-wire control and autopilot development, it serves as a tool to prepare flight-test campaigns. Dassault and EASA even perform some otherwise dangerous certification tests, such as the autopilot’s minimum-use height.
On the Falcon 5X, fly-by-wire software has been designed from scratch, although it retains the 7X’s software philosophy. “But we have some new control laws, due to the new control surfaces,” an engineer explained. The Falcon 5X’s flaperons will combine the roles of ailerons and flaps. One expected benefit is creating drag without spoiling lift, thus keeping a lower angle of attack at approach and landing, the engineer added.
The Falcon simulation bench can be linked to the “Falcon global test bench,” which reproduces aircraft systems such as computers, actuators, hydraulic systems, pneumatic ducts and so forth.
Falcon 5X development will use three test aircraft, Deleume said. The first will be for flight envelope expansion and the second for performance and systems evaluation. The third will be dedicated to cabin system tests and extreme weather campaigns, thus preparing for entry into service.
The Falcon 5X campaign will total 1,500 flight hours in 500 flights and 20 months, according to Dassault’s plan. Some 1,000 analog parameters will be recorded. Falcon 5X certification is anticipated late in 2016 and entry into service in mid-2017.
Sixteen pilots will be involved in the two flight-test campaigns, Deleume explained. For six or seven of them, this will be a primary job, while the remaining nine or 10 will simultaneously participate in Dassault’s military activities. One of the 16 pilots was hired in September, in anticipation of a busy year for the flight-test team.

Falcon 8X, Falcon 5X Move Closer To First Flight

As the first two test aircraft are practically assembled, Dassault has been using a cockpit test bench to develop fly-by-wire controls.

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