We Fly: Dassault Falcon 6X

The Falcon 6X is, by far, Dassault’s largest, heaviest, and most powerful business jet in the 60-year history of its business jet production line.

The 6X represents a sea change in Dassault’s design focus. Falcons always have appealed to pilots, engineers, and technicians—lean, nimble, and hyper fuel-efficient.

Now, passenger comfort has become the top priority. The latest Falcon jet offers a wider floor and taller cabin than any other purpose-built private jet in current production and promises to have mid 40 dBA super-low interior noise levels. 

This results in a nearly 38-ton aircraft at max takeoff weight, so I wanted to find out if it still had the famous agility of previous Falcon jets, ones quite clearly inspired by Dassault’s famed Mirage and Rafale fighters. Or, considering its apparent heft, would it handle more like a tour ’Bus from Toulouse?"

A. Single or dual FalconEye head up displays with40-degree wide and 30-degree vertical fields of view are highly desirable options.

B. EASy IV primary flight displays provide 3D depictions of airport environments, including sign posts for taxiways, runways and ramps. Sirius XM satellite radio weather, ADS-B IN traffic advisories, and Honeywell ROAAS also are available.

C. The fly-by-wire sidestick commands pitch and roll attitude. Dassault uses path stable pitch control law for “carefree” handling.

D. Left and right tablet computer docking stations provide a full range of electronic flight bag functions.

E. The 6X is one of few business jets to have both all-en-gine and one-engine-inoperative autothrottle functions.

For the record, the Falcon 6X actually grew to be bigger in cabin volume, heavier overall, and more powerful than originally intended. Development began in 2009 as Falcon 5X when Dassault abandoned plans to develop a new super-midsize aircraft in favor of a much larger and longer-range next-gen model. The Falcon 5X was announced in October 2013. Dassault planned to deliver the aircraft to the first customers in late 2016.

Dassault’s design goals were to create a new standard in cabin comfort by offering business aviation’s widest and tallest cabin, to achieve 15 percent better fuel-efficiency than competitors, and to preserve competitive speed and range. When launched in 2009, the Falcon 5X’s main competitors were the 4,200 nm range, Mach 0.80 [459 ktas] Gulfstream G450; and the 5,100 nm range, Mach 0.82 [470 ktas] Bombardier Global 5000. Dassault targeted 5,200 nm with eight passengers at 459 knots true for the Falcon 5X, enabling it to fly from Los Angeles to Paris on the same fuel that a G450 would need to fly from Los Angeles to Reykjavik.

Being a Falcon, it would be a technological tour-de-force, starting with its digital fly-by-wire flight controls. Dassault pioneered FBW in business jets with its Falcon 7X that entered service in 2007, borrowing heavily from technologies it had used for 40 years in its fighter jets, including its Mach 2-class Rafale.

Stability and performance are classic trade-offs in both military and civil aircraft designs. The more agile performance, the more stability must be sacrificed. The Rafale that I flew 16 years ago is a classic example. It’s so frenetically unstable that without digital flight controls, it’s nearly impossible for anyone other than a skilled test pilot to fly. Fit a Rafale with FBW, and it becomes as docile as a Falcon 10.

Unlike the Falcon 10, though, the Rafale will maintain its flight path if you let go of the controls, even with changes in speed or aircraft configuration. The Rafale also has full flight envelope protection. Yank and bank until you nearly black out. If you reef back the stick to the stops, you can’t overstress it, stall it,or cause it to spin. Dassault’s term is “carefree handling.” The pilot is free to concentrate on higher priority tasks, such as navigating around threats, checking six for bandits, delivering ordnance on target, or shooting down the bad guys.

Unlike the latest fighter jets, all Falcon jets are inherently stable. But, as with its military aircraft, Dassault upgraded its newer Falcon jets with FBW controls to slash pilot workload, incorporate flight envelope protection, and improve passenger comfort. Simply put, FBW makes the Falcons easier, safer, and more comfortable to fly. 

The Falcon 5X would have Dassault’s latest version of FBW flight controls, integrating nose wheel steering, plus slats and flaps. It also would be the first business jet to be fitted with flaperons, trailing edge devices that combine flap and aileron functions. When deflected in harmony with the ailerons, flaperons increase roll control authority, thus improving controllability at low speeds. When the flight spoilers are used, the flaperons deflect downward while the ailerons deflect upward to increase drag, minimize buffeting and unload the outboard wing sections. Note to self: The flaperons could make it lither than it looks.

Two enabling technologies were the keys to the Falcon 5X’s success. First was Dassault’s unmatched ability to build lightweight, low-drag airframes. TheFalcon 5X’s empty weight would be 5,000 pounds less than a G450 and 12,000 pounds lighter than a Global 5000. Second was Safran’s new 11,450 lb.-thrust Snecma Silvercrest turbofan engines, which promised 15 percent better fuel efficiency than competitive engines, along with considerably lower emissions.

The Silvercrest would be Safran’s first fully homegrown civil aircraft turbofan. The challenges proved too daunting, especially in developing the core or high-pressure section. After Silvercrest failed to meet a series of performance benchmarks, causing unacceptable delays in the Falcon 5X certification campaign, Dassault fired Safran as engine supplier and halted the Falcon 5X program in late 2017.

Safran subsequently settled with Dassault for €250 million. But, Dassault had already invested several million more euros in the Falcon 5X, so it wasn’t about to cancel the program entirely. It swiftly moved to morph the Falcon 5X into a new model, soon to be launched as the Falcon 6X.

Time was of the essence, as Bombardier planned to replace the Global 5000 with the faster and more fuel-efficient Global 5500, and Gulfstream was about to drop the dated G450 for the 30-knot faster, higher flying, roomier, and more fuel-efficient G500, first of the G-VII family. Bombardier also added more fuel capacity to the Global 5500, stretching its range to 6,000 nm. The Gulfstream G500 could fly 5,400 nm, 1,200 nm more than G450. The competitive landscape obviously had undergone a revolution in the years since the Falcon 5X was announced.

To prevent its next-gen Falcon from becoming an also-ran in the race with the Canadians and Americans—or worse yet, a still-born—Dassault needed to find a suitable replacement engine without delay. It also needed to give the aircraft more range to keep it in the running with the updated Global 5500 and clean-sheet G500.

By the end of 2017, Dassault found an engine for the Falcon 6X. It was the 13,500 lb.-thrust Pratt & Whitney PW812D turbofan, essentially a scaled-down version of the PW814GA Pure Power engine used on the Gulfstream G500. Of prime importance, PW800 series engines were a low-risk choice, as they use the same high-pressure sections as Pratt & Whitney’s geared turbofan engines. In airline use, the GTFs have logged more than 18 million hours of fleet time. The engine core has proven to be rock-solid reliable.

The PW812D produces 2,000 pounds more thrust than the Silvercrest engine, but a pair add 900-plus pounds of installed weight. Dassault countered this weight by stretching the Falcon 6X fuselage 20 inches ahead of the wing and adding an extra cabin window on each side. The stretch makes the cabin 4 percent longer, affording passengers more comfort.

Dassault also added 5,590 pounds more belly tank fuel ca-pacity to boost maximum range by 300 to 5,500 nm. However,that’s at Mach 0.80 or 459 ktas, compared with Mach 0.85 for the competition. The Falcon 6X’s range at Mach 0.85 drops to 5,100 nm.

The PW812D engines, fuselage stretch, and bigger belly tanks boost the Falcon 6X’s empty weight by 2,700 pounds. With extra fuel, max takeoff weight is increased 7,860 pounds compared to the 5X. The considerably more powerful Pratt & Whitney engines endow the Falcon 6X with a better thrust-to-weight ratio than the Falcon 5X with Silvercrest turbofans, so the aircraft still is a strong performer. Even though wing area remains the same and wing loading goes up 11 percent, the Falcon 6X takeoff distances at max take-off weight are very close to those of the competition. On more typical 2-hour trips, the Falcon 6X needs less than 3,000 feet of pavement when departing a sea-level, standard-day airport. That’s on par with a Beechcraft King Air 360.

I traveled to Dassault’s flight test facility at Istres-LeTubé to fly the Falcon 6X a few months before it was slated for FAA and EASA certification. A visit to LeTubé is always a treat because you’re up close to the Mirage 2000, Rafale, and C-135 air refueler operations. The day I flew the Falcon 6X, we had to share the runway with Rafale pilots in the “bounce pattern”—field carrier landing practice in preparation for carrier qualification. 

Serial Number 4, the aircraft I would fly, is intended to be a customer demo aircraft, so it was equipped with a whole raft of options, including the FalconEye wide field-of-view HUD and combined vision system, one of the best with which I’ve yet flown; optional Iridium and KA-band SATCOM for high-speed WiFi and VOIP mobile phone calling for the passengers; cabin humidifier; HEPA air conditioning filters; extended galley, and several other items that added 1,237 pounds to its empty weight. Even so, the tanks-full payload was 1,750 pounds, enough for eight passengers and their bags, plus plenty of catering and beverages. For my demo flight, I would fly left seat, Dassault’s chief test pilot Phillipe Duchateau would be in the right seat as my instructor, and Fabrice “Tom” Valette—lead Falcon 6X test pilot—would occupy the jump seat as safety pilot. As the aircraft was still in experimental status, the uniform of the day would be blue Nomex flight suits for the three of us.

The demo was also the 54th test flight, so we carefully briefed the maneuvers on the test card [aka “the dance card”]. The main purpose of the mission was to provide me with the opportunity to evaluate the aircraft’s stability and agility.

Filled with 17,000 pounds of jet-A and accounting for start and taxi fuel burn, our computed takeoff weight was 59,000 pounds. That was enough fuel to fly from Istres-Le Tubé to Gander, Newfoundland, or Dubai, UAE. If the aircraft had been full of fuel and with eight passengers aboard, we could have flown from Le Tubé to Seattle, São Paulo, or Ho Chi Minh City [aka Saigon].

Using the normal slats and flaps 2 position for takeoff, our V speeds were 117 knots for the V₁ takeoff decision speed and V_R rotation speed, 121 knots for the V₂ one engine inoperative climb speed, and 151 knots to retract slats and flaps. Those comparatively low V speeds are worth noting because the Falcon 6X has the highest wing loading of any current production purpose-built business jet. Without Dassault’s signature full-span leading edge slats, those V speeds would have been at least 20 knots higher.

Belting into my seat, I was immediately impressed with the size of the flight deck windows and room for pilots. The window area is a third larger than in the Falcon 8X. I’ve not flown a business jet with bigger windows or better visibility outside of a Cirrus Vision Jet.

Dassault’s flight test ground crew already had the APU running, so everything up front had electrical power when we entered the flight deck. Duchateau was busy programming the aircraft’s EASy IV [enhanced avionics system, fourth-generation] computer with crew weights, fuel load, and allowances for spares and stores.

The 6X has much shorter checklists than previous Falcons because several systems are more automated. But the flow pattern of checks and flight deck layout closely resemble those of its predecessors that I’ve flown. There just are fewer switches, buttons, and knobs that need to be touched during normal operations. When necessary, however, it’s easy for pilots to intervene and exercise adult supervision over the computers. Dassault takes special steps to avoid pilots having to ask, “What’s it doing now?”

To start the engines, I needed only to move the throttles to idle and turn one central knob to “start.” That would automatically initiate start, first for the right engine, then for the left. For this flight, though, we overrode the automatic two-engine start feature and started one engine at a time to allow the ground crew to make some post-start checks related to flight test.

Once the main entry door was closed, I was impressed with the low interior sound levels. Releasing the parking brake, it took just a little thrust to start the aircraft moving. All the FBW Falcons do away with steering tillers. It’s all done through the rudder pedals, with nose wheel steering progressively increasing with pedal movement and decreasing with taxi speed. I found the brakes to be a little touchy, but my technique got better with practice.

EASy IV, similar to Gulfstream’s Symmetry avionics package, provides 2D airport moving maps and 3D synthetic vision of the airport environment, including signposts for ramps, taxiways, and runways; depictions of buildings; and, eventually, ADS-B In images of proximate aircraft and ground service vehicles. Upgraded EASy also supports Sirius XM weather and Honeywell’s Runway Overrun Awareness and Alerting System.

These aren’t gimmicks. Every pilot with whom I’ve spoken raves about Sirius XM satellite weather as a strategic planning tool. ROASS warns pilots of landing fast, touching down long, or braking too gently. And importantly for me, taxiing between ramp and runway in poor visibility and/or darkness is much more challenging than flying it from takeoff to touchdown. Dense fog increases the risks of getting lost on the ramp, rolling off the pavement, or having to slam on the brakes. EASy IV’s 3D airport moving maps take a lot of the stress out of ground maneuvering.

For flight, in contrast, I like to spend most of my time looking out of the aircraft, not head down, hawking the instrument panel. That’s when the optional FalconEye HUD showed its value. All imagery is focused at infinity, so it enhances distance vision that’s so critical to spotting risks. Aircraft attitude, flight path trajectory, heading, and bank angle, among other essentials, all are displayed 1:1 with the outside world, so the HUD promotes situational awareness using basic visual references. You only have to glance down occasionally to check fuel quantity, engine instruments, and systems status. The FalconEye also has multi-spectral infrared and visible light sensors that provide certified enhanced vision system credit, along with synthetic vision, enabling the crew to earn approval to fly down to 100-foot ceilings on instrument approaches. For me, the HUD is the greatest safety breakthrough since the advent of the windshield.

Once cleared for takeoff, we used a FOD prevention technique to reduce the chance those pricey PW812Ds would swallow debris that could damage them. I advanced thrust to 52 percent N1 fan speed, waited until the aircraft was rolling at 45 kias, and then pushed forward on the power levers to the stops. At our relatively light weight, the aircraft’s weight-to-thrust ratio was nearly 2:1. Acceleration was a whole lot sportier than the Falcon 8X I last flew a few years ago.

When Duchateau called “V1, Rotate!”, mild back pressure on the sidestick was all I needed to set 15 degrees nose up. With a positive rate of climb, we retracted the gear. As the FBW system uses path-stable pitch control law, I didn't need to move the sidestick as the 6X accelerated, automatically trimming the horizontal stab. At V₂ + 30 knots, we retracted the slats and flaps, turned toward the Mediterranean, engaged the autothrottles, and settled into a 250-kias climb to 15,000 feet.

Once leveled at 15,000 feet, it was time to begin the big dance. This would start with baby steps, progressing to break dance moves. I first used gentle sidestick pressure to roll the aircraft into a left 30-degree angle of bank and then reversed it to the right. With a light touch, the Falcon 6X moved with the uber-soft restraint. If passengers had been aboard, there was no chance of rattling silverware, shifting china plates, or spilling that 2010 Chateau Dassault St. Emilion.

Then, I started making more assertive sidestick inputs, rolling the aircraft rapidly between 60 degrees left and right. Healthy springs inside the sidestick control boxes prevent pilots from making such spirited moves inadvertently, but if you muscle this aircraft around at 250 knots like a 25-year-old Rafale pilot, it responds with alacrity and aplomb.

Slow-speed agility usually is more of a challenge for a large-cabin jet. I disengaged the autothrottle and let the airplane decelerate until the sidestick was on the backstop. The outboard slats automatically extended,and we were alerted by aural and visual warnings that we should lower the nose and recover. We kept the sidestick firmly against the stops as the aircraft stabilized at VMIN, the highest angle of attack allowed by the FBW system, which is just a few knots above aerodynamic stall. Nose attitude eased down to just below the horizon and the VSI plunged.

With the sidestick fully aft, I started rolling the aircraft 30 degrees left and right. In spite of the abuse, the Falcon 6X sank as gracefully and obediently as with a dozen other Falcons I’ve flown. High alpha maneuvering is as dramatic as in a Piper J-3 Cub.

Next, we configured the aircraft for landing with gear down and slats/flaps extended, stabilizing it at the 125-knot V_REF landing reference speed, plus 10 knots padding for maneuvering.

Starting with gentle banks, I progressed to full sidestick deflection rolls to 40 degrees left and right. Whoa. That’s when the flaperons revealed their true roll control power. The Falcon 6X may look plump on the ramp, but in the air I found it as impressively agile as older Falcons.

After our stability and control checks, it was time to return to Istres-Le Tubé for abbreviated pattern work. To hasten our descent, I pulled the air brake lever back to position 1 [AB1]. The ailerons deflected up and the flaperons deflected down, creating plenty of drag without changing nose attitude significantly. There was almost imperceptible airframe buffeting. Dassault plans to certify the use of AB1 with gear, slats, and flaps extended to stabilize aircraft descent rate for steep approach approval, needed for London City and Lugano, Switzerland, airport operations. I’ll wager it will be just as valuable for flying into Aspen, Colorado, with its 6.49-degree or 6.59-degree final approach glide paths.

If maximum drag is required, say for an emergency descent, pulling the lever back to AB2 causes all four spoiler panels on the wings to extend, resulting in a high rate of descent. Normally, the spoilers only are used during landing roll to dump lift, thus improving main wheel traction and braking effectiveness. All the trailing edge high lift devices also deflect upward onlanding to enhance lift dump.

As we approached the airport, we noted a 20-knot overshooting left crosswind on Runway 33. Not a problem in this aircraft. I just crabbed into the wind until 50 feet above the concrete, where I pulled the thrust to idle, held the nose attitude relatively flat, pushed in a little right rudder, and settled in for a feathery touchdown. That surely was a reflection of the aircraft’s long-travel, soft oleo main landing gear, not my flying finesse. Duchateau commented that it’s nearly impossible to embarrass yourself by crunching down in this aircraft, even for newbies.

We reconfigured on the roll for a touch-and-go and flew around for a second landing. This time, Duchateau had me offset 500 feet to the right of centerline. About 1,000 feet above touchdown height, he had me make an aggressive alignment maneuver to centerline. The aircraft responded crisply, precisely, and confidently. At 500 feet, we were stabilized on centerline and VASI glidepath. Using the same landing technique as before, the aircraft touched the runway as though I had logged 2,000 hours in type, not two.

The Falcon 6X, as with all other aircraft, has its design trade-offs. A 5,500 nm trip flown at the Falcon 6X’s Mach 0.80 long-range cruise speed takes 45 minutes longer than one flown in a competitor cruising at Mach 0.85. Push it up to Mach 0.85, and the range drops to 5,100 nm, still sufficient for Paris to Portland, London to Tokyo, or Beijing to San Francisco.

Unrefueled short-haul missions are this aircraft’s strong suit because of its comparatively high max landing weight. Depart Van Nuys for a five-leg trip to Tucson, El Paso, Salt Lake City, Portland, and back to Van Nuys, and you’ll never tap the fuel truck until you’re back in Southern California.

You can also fly from Washington, D.C., to Teterboro, then on to Rome—across the pond—without refueling. That's a nice flight plan to consider.

Passengers, not pilots, buy most large-cabin airplanes. Along with speed and range, comfort and convenience weigh heavily on the purchase decision. Falcon 6X’s high wing loading and flexible wing structure, along with the stability controls built into its FBW system, should make it tops in class for a pillow-soft ride.

The cabin has 30 windows, each about 10 percent bigger in area than on older Falcons, that flood the cabin with daylight and that make it feel larger than it measures. Just ahead of the galley, there’s a crew lavatory and swiveling third crewmember seat.

The 10.2 psi pressurization system assures cabin altitudes at or below 4,800 feet at typical cruising altitudes. The 155 cubic foot aft baggage compartment is fully accessible in flight. There is another 76 cubic foot unpressurized compartment for golf clubs, skis, snow-boards, or mountain bikes.

The standard 12-seat floor plan includes a typical four-chair club section up front, a four-seat conference grouping in mid-cabin, and a three-place sofa sleeper plus single chair in the aft cabin. There are power outlets throughout the cabin for tablets, laptops, and phones. The optional satcom WiFi system provides dozens of channels of audio/visual entertainment and full-time broadband connectivity.

Quite clearly, the Falcon 6X delivers a crème de la crème passenger experience befitting a Comtesse de Champagne. Up front, I’ll wager that pilots will find that it provides that it tops any Falcon they’ve previously flown for handling ease, situational awareness, and low workload. As Dassault’s first foray into ultra-large private jets, the Falcon 6X retains top honors as one of the nicest flying airplanes ever to wear rouge, blanc, et bleu.

This article was originally published in the May 2023 Issue 937 of  FLYING.