On the surface, 3½ feet — just over a yard — might not mean much to most people. Spread your arms out and that’s about it. But in a business jet, every inch of extra space, like every pound of weight designers can eliminate, translates into additional customer options for organizing that new cabin.
Aboard ultralong-range business jets capable of 12- to 14-hour nonstop journeys, such as Dassault’s new Falcon 8X, Gulfstream’s G650 or Bombardier’s Global 6000, there are two sets of customers to please who care about extra space: the people relaxing or working in the cabin and the flight crew up front. Of course, flying means more than simply getting there. On ultralong-range airplanes, mitigating crew-fatigue issues is just as important for a successful flight as cabin amenities are to owners.
As the 8X firmly established Dassault in the ultralong-range category, company designers, already renowned as creative masters of small spaces, turned that 3½ feet of extra space into a fatigue-alleviating option offering crew members a private spot to kick back when they spend a working day and a half aloft. The company says most new 8X buyers are choosing the crew-rest option when they purchase this follow-on to Dassault’s popular Falcon 7X. Some 260 copies of the 7X are flying today, while 15 of the new 8Xs have been delivered to date, many to 7X operators.
Dassault invited Flying to evaluate the 8X recently at the company’s manufacturing facility near Marseille, France. The visit included a few hours of flying as well as conversations with the engineers, designers and test pilots who managed the project to its June 2016 certification.
Updated Systems
The 8X adds two fuselage plugs to create the additional 3½ feet of airframe length. Dassault chose the more powerful D model of the Pratt & Whitney Canada PW307 engines, which added 320 pounds of additional thrust per side while reducing specific fuel consumption by 1.5 to 2 percent. Flat-rated to 6,722 pounds of thrust at 17 degrees Celsius, the 8X, sporting a beefier landing gear, demands only about 170 feet of additional takeoff runway at maximum gross weight, while retaining the 7X’s short-field performance and low ref speeds.
The new 8X gained 3,000 pounds of additional fuel capacity to create the nearly 6,500 nm range. Designers reworked the wing tanks, adding additional fuel space in the center belly section. Dassault admitted the 7X had difficulty reaching Singapore from Paris, an easy trip in the 8X. Los Angeles to Hong Kong and Hong Kong to London were also tough for the 7X, but not for the 8X. From Cannes, an airport with significant weight-limiting noise restrictions, the 8X can make New York City direct. New York nonstop from London City’s challenging 4,948-foot runway now works.
The 8X retains the safety and performance margin provided by a third engine eliminating the required diversion airport on a twin. Dassault says that third motor knocks off as much as 45 minutes of flight time on a long trip. The 7X and 8X share a common type rating, requiring only two days of training for those experienced in the earlier airplane.
The cockpit was created around Honeywell’s Primus Epic III avionics, featuring four 14.1-inch screens to display automated checklists, graphical flight planning and weather, all managed through a cursor-control device — essentially a computer mouse — for each pilot. The cockpit offers an optional dual widescreen head-up display, incorporating FalconEye — a blend of synthetic, database-driven terrain mapping with actual thermal and low-light camera images. Certified in February 2017 and ordered by four out of five 8X buyers, FalconEye increases situational awareness, day or night, during operations in fog, mist, snow and other severe weather. This 8X uses Honeywell’s next-generation 3-D color radar with enhanced turbulence-detection capabilities.
Recognizing an 8X is tough unless the observer notices the two extra windows per side on the longer cabin. The 8X also sports an 86-foot-3-inch wingspan and sits an inch closer to the ground than the 7X. The 8X’s wheelbase is 2 feet wider than the 7X to support the 3,300-pound-higher gross weight. Offsetting some of that increase, Dassault engineers created the 8X’s wing spars out of solid blocks of aluminum, reducing overall wing-structure weight by 600 pounds. Kevlar or carbon composites are used for the nose cone, vertical fin, horizontal stabilizer, winglets and similar secondary components.
Flying by Wire
With decades of fly-by-wire heritage on the Mirage and Rafale fighters, Dassault didn’t think twice about creating the 8X as a fly-by-wire airplane like the earlier 7X. Fly-by-wire means pilot input to either of the 8X’s passive sidesticks — replacements for traditional control wheels — does not actually move the flight controls. Sidestick movements are recognized by onboard computers that signal hydraulic actuators to move the flight controls. For pilots transitioning from a control-wheel aircraft, the 8X’s passive sidesticks can take a bit of getting used to because moving one has no effect on the other, a characteristic some critics detest. (Competitor Gulfstream chose active sidesticks for its new G500/600 models.) Replacing those traditional control wheels does offer some real benefits though, such as cutting another 50 pounds of weight, not to mention the increase in available cockpit real estate.
The philosophy of flying either the 7X or the 8X is a bit different from traditional airplanes. In the 8X fly-by-wire system, the pilot essentially points the aircraft where they want it to go and releases the sidestick. The computer considers the pilot’s request and adds just the right amount of control input to accomplish the job. This change eliminates a traditional trim control, as well as some of the tactile control feedback many pilots are accustomed to. In a standard 25-degree bank, for example, the pilot can simply let go of the sidestick once reaching the desired bank angle. The computer adds in the right amount of back pressure to hold altitude. To appease the computer-anxious aviator, Dassault’s digital flight-control system operates with three main flight computers backed up by three secondaries. There’s also an analog computer controlling the flight spoilers via rudder pedal displacement, as well as backup trim for the horizontal stabilizer through a switch on the center pedestal.
The fly-by-wire system, programmed to the 8X’s structural limits, provides nearly complete flight-envelope protection. The computer won’t allow the pilot to overstress the airplane, even with jerky sidestick movements that would induce stomach-floating Gs in traditional airplanes, making it nearly impossible to stall or overspeed the 8X. When the computer senses either condition, it reduces angle of attack to avoid a stall or brings the nose up out of a dive.
The heart of the digital flight-control system is pretty simple and demands only that the pilot understand there’s a very slim chance of the fly-by-wire computers failing. If that should occur, the first level of control degradation means that flight-envelope protection has moved down a notch from the use of “normal” to “alternate” control laws. In alternate law, some envelope protections disappear; should a further degradation to direct law occur, only then is the pilot essentially flying an airplane with no flight-envelope protections.
Back in the Cabin
The 8X’s longer cabin meant Dassault could easily offer a wide range of customization options. Designers settled on three primary versions, known as short, mid and large entry. Each offers two three-seat divans in the rear of the cabin, as well as a separate four-chair table arrangement about midcabin with two opposing seats on either side near the forward bulkhead.
It’s in front of the main cabin where most of the customization takes place, however. In the large-entry version, the 8X offers a crew rest station with a 78-inch bed and a large galley. Mid entry offers a smaller galley and a small couch near the front door, and the short entry comes with a small galley and a belted seat near the front door. The 8X comes standard with a separate vacuum toilet aft of the cockpit and a rear-cabin shower option. The interior-design people told engineers the new cabin cried out for more natural light to avoid claustrophobic sensations. The result was the two new windows per side. The 8X’s shower option consumes less space than the one offered on the 7X, but still provides 30 total minutes of cleansing time thanks to an 88-liter water tank. Using a dedicated pump to remove the air, the shower water is then dumped overboard.
Infotainment is already changing on the 8X. Early aircraft were delivered with Rockwell Collins FalconCabin HD+ entertainment systems that included a DVD player, but recent deliveries are being upgraded to a distributed system that sends content directly to individual iPads, using a Rockwell Collins onboard server.
To reduce fatigue on long flights, the Falcon’s 10.1 psi pressurization system creates a 6,000-foot cabin at FL 510, with considerably lower cabin altitudes in the normal cruise altitude ranges, such as a 1,000-foot cabin up to 27,000 feet. Dassault says cabin noise has been reduced compared with the 7X and actually measured at 2 to 3 db lower — a significant drop. When it comes to the outside-noise footprint, the 8X has bested its earlier edition too. Although both the 7X and 8X meet the FAA’s strict Stage 4 noise standards, the precise numbers differ. The 7X’s measured noise levels (EPNdB) are 82.3 flyover, 90.1 lateral and 92.6 on approach; the 8X on flyover is 81.5, 88.9 for lateral and 90.6 on approach.
Flying the 8X
The auxiliary power unit was already running on our flight-test airplane, F-WWQA, as I walked across the ramp at Istres, where Dassault shares facilities with the French air force. With me were Dassault’s senior chief test pilot Philippe Deleume and test pilot Hervè Laverne. We planned that Hervè would sit right seat, with Philippe in the jumpseat since Philippe and I had flown together on previous trips.
Because F-WWQA was still decked out with tons of critical test equipment, I wasn’t able to experience the luxury of a completed 8X cabin during my flight, nor the quality of the noise suppression in the cabin. I was, however, able to visit with Dassault’s interior designers, who explained the meticulous efforts of their team to personally interact with customers to create a truly unique cabin on each Falcon, even if that means bringing interior samples to a potential owner thousands of miles away from France.
Climbing into the cockpit of a sidestick-equipped aircraft should be a breeze for a person of almost any size since there’s no control wheel getting in the way. Most pilots will get comfy rather quickly with the extra room in front of the big cockpit displays. The Falcon offers pullout trays for the more important pilot duties, like where to place a lunch tray, or filling out any critical paperwork, of course.
With full-authority digital engine control, it took only a couple of quick twists on the start switch to bring all three of the Pratt & Whitney engines to life. Fadecs have, in fact, turned failed starts almost into a thing of the past, since they can recognize and fix an engine ignition problem before the human even notices the symptom. Our flight test occurred on a cool day, 5 degrees Celsius, with about 13,000 pounds of fuel bringing the 8X up to nearly 50,000 pounds — considerably less than the airplane’s 73,000-pound maximum. There was a gusty breeze blowing as I taxied to Runway 33, but the 8X felt rock steady on its wider gear, perhaps a bit more so than I remember when flying the 7X. Because the 8X uses rudder pedals for nosewheel steering rather than a tiller, the trick for a new pilot is to keep the power back at idle most of the time so as not to drag the brakes, which could lead to an expensive premature replacement.
Before startup, Hervè and I discussed engine-failure procedures, noting that the loss of one on takeoff with a three-engine aircraft is serious, but not quite the issue it is in a twin, especially if happens to the center engine. I agreed that should a failure occur, I’d enter a wide left downwind and return to the airport, after Hervè ran the engine-failure checklist, of course.
At lineup, the controller called the wind as 310 at 20 gusting 32. I added a bit of left aileron correction, but at our weight, the 8X acceleration was brisk, with the rotation speed arriving quickly. Rotation demanded only a slight amount of back pressure on the sidestick to pitch the nose to 14 degrees and allow the flight path cue to meet the flight director command. Autothrottles on the 8X don’t become active until 400 feet, just in case a problem pops up. Unlike those on the 7X, these autothrottles will operate if one engine fails. Flaps and slats came up passing through 400 feet. It only takes a few seconds to get comfortable pointing the Falcon’s nose somewhere, letting go of the sidestick and watching the airplane look for and hold that aerodynamic sweet spot.
At climb power, I hand-flew the airplane to 20,000 feet holding about 260 kias. I can only describe the rate of climb in the cold yet bumpy air as dizzying. Next I leveled off to try some steep turns. Crank in 30 degrees of bank, let go of the sidestick and the Falcon will sit there all day long, considering fuel of course. In a 60-degree bank, I needed to hold the nose up just a bit. When I let go of the sidestick, the airplane rolled back to maintain a perfect 30-degree bank. The results were pretty similar when I later rolled back and forth from one 60- to 70-degree turn to another after climbing the Falcon up into the 40,000-foot region.
During the flight-envelope demonstration, I tried everything to both overspeed and even stall the airplane, but the 8X would have none of it. When I tried yanking back on the sidestick, the airplane would gently reduce the angle of attack. With the throttles at idle power, the 8X’s wing continued flying as I slowed to about 95 knots with slats/flaps set to 2. I brought in some power to maintain 95 and rolled the aircraft back and forth steeply. I swear I heard the airplane say, “Is that all you got? … Yawn.” The Falcon’s marvelous controllability reminded me of flying an equally-controllable Cirrus SR22.
What should not be ignored in a fly-by-wire airplane like the 8X is the absolute precision with which the flying pilot can smoothly maneuver the airplane thanks to the superb flight path monitoring tools on the primary flight display — something I was reminded of a bit later in the VFR pattern. With clear VFR conditions, watching the 8X’s autopilot fly an instrument approach seemed like a waste of time, so I didn’t evaluate that option. But after only an hour and a half in the 8X, I would have felt very comfortable in poor weather should the need have arisen.
As I turned a 3-mile final for Runway 33 back at Istres, the wind was still blowing like crazy from the left. I crabbed slightly, and the airplane settled down nicely as if to confirm I’d found the right spot for the rest of the approach. We’d planned to fly to just below minimums and execute a go-around. Of course, just after pushing up the throttles on the go, my able copilot failed the right engine.
The 8X loves to fly, and the yaw toward the idled engine demanded only a touch of left rudder all the way around the pattern. On base, Hervè gave me back the right engine for a full-stop landing. Our reference speed worked out to be about 106 knots, but as I glanced at the PFD on short final, I realized the wind had slowed our groundspeed to just over 80. Once I touched down, the 8X was almost stopped before I had time to pull the single thrust reverser that pops out behind the center engine. Even with the gusty wind, the 8X trailing link landing gear made me look like I’d been flying this big airplane for years.
As we taxied in, Hervè asked my impressions. I found myself a bit lost for words. All I could do was smile. “Easy to fly?” he queried. “Not just easy to fly,” I replied, “but fun.” Jets are supposed to be business tools, practical machines. But then I remembered that most of Dassault’s test pilots who helped create the Falcons earned their wings in those Rafales and Mirages, where being responsive was an understatement.
Certainly a fully automated airplane like the 8X demands a crew with an in-depth understanding of the pros and cons of the technology in front of them, but when it comes to operations, this new Falcon should prove to be a worthy sibling to the 7X.
