Early flight testing of the Dassault Falcon 7X has concentrated on performance of the aircraft's fly-by-wire (FBW) flight control system – the first such application in a business jet. "Flying qualities are better than indicated by the fixed-base simulator," says Philippe Deleume, Falcon chief test pilot.
Beginning with the 5 May first flight, initial testing was conducted with the flight controls in "alternate law", without the flight-envelope protection normally provided by the FBW system. After the flight-control sensors were validated, flying switched to "normal law", which provides speed and angle-of-attack (AoA) protection, and the aircraft flown up to 15° AoA.
The 7X, which has relaxed longitudinal static stability for reduced drag, has also been flown with the FBW system in its back-up "direct law", providing unaugmented electrical signalling of the control surfaces. In this mode, the aircraft has less stability, but still has handling similar to that of the non-FBW Falcon 900EX, says Deleume.
After initial flights with a centre of gravity (CG) in the middle of the range, later sorties explored the maximum forward and aft positions, using an onboard water-ballast system to move the CG. Handling qualities were good, Deleume reports, adding: "The fly-by-wire is doing its job. The pilot gets the same sensation, regardless of CG."
Early flights have revealed the 7X "is a little aggressive on roll, too much like the Rafale", he continues, comparing the business jet to Dassault's latest combat aircraft. "We have to work that out and damp it a little."
Manoeuvres at 41,000ft (12,500m), which are "quite demanding" in previous Falcons, are "a piece of cake" in the 7X, he reveals, adding that landings have shown it is easy to flare the 7X using the sidestick controller – the first in a Falcon.
The second 7X will join the flight-test programme in July and the third aircraft, fitted with an interior, in September. A 400-flight, 1,200h flight-test programme is planned, leading to certification and first deliveries in the fourth quarter of 2006.
* Dassault expects to certificate the "Step 3" upgrade of its EASy integrated flightdeck in September on the Falcon 900EX and by year-end on the 2000EX. That is later than expected, says Olivier Villa, senior vice-president civil aircraft. Now in final flight test, Step 3 adds vertical profile, integrated lightning sensor and video display capability to the Honeywell Primus Epic-based EASy cockpit.
Dassault has, meanwhile, introduced a fixed-cost support programme called FalconCare, which provides new Falcon operators who do not have large fleets with nose-to-tail support.
GRAHAM WARWICK/GENEVA
Source: Flight International
