New Engines Drive Change From Falcon 5X to 6X

Dassault released details on its newest business jet, the Falcon 6X, during a day-long technical briefing today. The latest model is a replacement for the 5X, a project canceled due to multiple delays in the development of its proposed Snecma Silvercrest engines. The 6X will have Pratt & Whitney Canada PW812D ("D" for Dassault) engines. The 13,000- to 14,000-pound-thrust PW800 family has logged more than 20,000 test hours. It has also been selected to power the Gulfstream G500, with the PurePower PW814GA, and the G600 with the PW815GA.

“I had no choice to stop the 5X program and find the best possible engine,”  chairman and CEO Eric Trappier told reporters gathered in the company’s large Le Bourget hangar, where he unveiled a large model of the new 6X. He revealed that in 2015/2016 Dassault engineers began developing a Plan B for the Falcon 5X when the Silvercrest engine began experiencing problems with its high-pressure compressor. As the troubles intensified, the company took the opportunity to design an aircraft with more range and more space. Olivier Villa, Dassault’s senior v-p of civil aircraft, told AIN, "We talked with Pratt & Whitney Canada, and they modified their engine somewhat for us. And we adapted the airplane to match the engine." 

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The engines are far from the only change. The new twinjet will have a 20-inch-larger cabin, enabling either a larger aft lounge area or a choice of larger forward galley or a crew rest area. The 6X will also have a 300-nm range increase over the 5X (to 5,500 nm), and first deliveries are scheduled for 2022. As for commonality with the 5X, Villa said, “Much of the systems architecture will be retained—the fly-by-wire system is one step beyond that of the 8X—and there will be some commonality in the cockpit and the empennage. But otherwise, it is a thorough redesign.”

For example, he said, though the aerodynamics of the wing remain, heavier loads required significant changes. “There are no common parts,” Villa said. He also added that the extra fuel required for the additional range caused Dassault to switch to a nitrogen-based fuel pressurization system. “We were first to have a pressurized fuel system, which is safer for crossfeeding. And our experience with military aircraft led us to add a nitrogen system for the 6X. It’s a first for a business jet, and the ultimate in fuel system safety,” he said.

“It wasn’t something we wished,” said Villa of the 6X program, “but we’re excited by the capability, and customers have responded enthusiastically.”

UTC Aerospace Systems (UTAS) will supply the nacelle system for the 6X, including an inlet, fan cowls, thrust reverser and an engine build-up system. “This program will enable us to bring the many new nacelle system technology advancements we’ve developed and matured for large commercial aircraft over the last 15 years to the business and corporate jet market,” said UTAS Aerostructures president Marc Duvall.

Trappier noted that most customers switched from the 5X to 7X and 8X as they “didn’t want to wait,” but some are in contract negotiations now to switch to the 6X. He expects some to be finalized in “the next few days.” The price will be about the same as the 5X, $47 million “in 2018 economic conditions.”

When Dassault decided late last year to drop Safran's Silvercrest engine that had already delayed its Falcon 5X by three years (the actual engine delay was four years), the obvious replacement choice was the PW800. However, the higher thrust range would necessitate a redesign, and for this reason, among others, the company decided to ditch the 5X name and “relaunch” the Falcon 6X. Dassault made the announcement in late February and followed up with a technical briefing on March 8.

During the “unveiling,” chairman and CEO Eric Trappier said, “The more powerful engine results in a longer range [up by 300 nautical miles to 5,500 nm].” He added that the 6X “retain[s] the same wing that proved so efficient in our short flight-test [program for the 5X]" and that "we’ve kept the new flight control system too.” Finally, he added, “It will also feature the most spacious cabin and largest cross-section in the large [business jet] segment [at 2.7 meters/8.9 feet].” Dassault plans to “fly [the aircraft] in less than three years and have the aircraft on the market in four,” said Trappier, a goal he acknowledged is challenging.

Pratt & Whitney Canada proposed the PW800 that uses the new core developed for its range of geared turbofan engines that now powers airliners such as the Bombardier C Series and Airbus A320neo family. The PW814, certified last year, was developed for the Gulfstream G500/G600 and uses the midsize core from the airliner engine, but without the reduction gearbox. The 6X’s PW812D uses a smaller core.

Switching to the Pratt & Whitney Canada engine results in a thrust increase for the 6X from 11,450 pounds per engine with the Silvercrest to 13-to-14,000 pounds with the PW812D, with its 44-inch single-piece fan and 4.5-to-5.0 bypass ratio. Specific fuel consumption of PW800s is some 10 percent less than that of current, in-service engines, according to P&WC.

Olivier Villa, senior executive v-p civil aircraft, who was instrumental in the 5X program, told the audience, “We’ve kept the basis of the 5X and optimized the new design around the new engine. We’ve increased the length of the cabin by 20 inches,” which he added later was a “stretch” in front of the wing due to the greater weight of the larger engines. “It will also have the brightest environment, with large windows and skylight [a popular feature that has been retained from the 5X design].” The aircraft will be offered with 12-,13- or 14-passenger versions of the cabin, he said. Cabin altitude will be “3,900 feet at FL410—and it will be ‘whisper-quiet’ like the 8X,” which measures 49 dB on average, with air quality “up to 10 times better than an office building.” Cabin height will be 78 inches from floor to ceiling, the baggage compartment will be 155 cubic feet “with an additional, unpressurized compartment of 76 feet, three inches.”

Villa noted that the new mtow will be 77,460 pounds, “So we keep a very good ratio [85 percent] of maximum landing weight to maximum takeoff weight” which “means it can do a short hop and then, unrefueled, fly 3,600 nm, for example, Washington-to-New York and then [on to] London, Paris, or Geneva. You won’t do that with our competitors,” said Villa, as he presented a slide showing the Gulfstream G500.

In addition, the aircraft will “still be able to use challenging airports, including, of course London City Airport, with its steep approach and noise controls.” And Villa pointed out that the 6X’s takeoff speed will be “15 knots slower than [the equivalent] Gulfstream's.”

Avionics

He said the cockpit was built around the EASy 3 platform (a development from the in-service 8X), with the Honeywell IntuVue RDR-4000 radar and FalconEye EVS/SVS head-up displays, which are "unique in the market.” The 6X will also be improved over the 5X, given the additional development timescale, with “smart systems, but with the pilot still in the loop. This reduces by a factor of three the number of pilot actions needed to power up and start the aircraft—to only five steps.” FalconSphere II electronic flight bags (EFBs) will be integrated into the front instrument panel (pilots can use their iPads or other tablets for flight planning away from the aircraft).

Villa claimed that Falcons have “more than 60 percent greater control-surface efficiency, increased maneuverability, and safety [as a result of] the systems DFS introduced with the 7X and improved with the 8X.” The 6X carries forward the 5X's flaperons (“from our military heritage” such as the Rafale fighter) and with the control surfaces working in tandem, lift-over-drag augmentation improves “visibility, control, and comfort during a steep approach.” It also has a closed-loop autotrim that further reduces pilot workload. “It will set the flight path, and the system does all the necessary adjustments.”

Another new 6X feature, even compared to the 5X, will be the introduction of OBIGGS (On-Board Inerting Gas Generation System), using nitrogen to pressurize the fuselage fuel tanks. This minimizes the risk of ignition of fuel vapor. It is the first nitrogen-based system for a business jet, said Villa, again citing synergy with Dassault's military aircraft designs.

Smarter Maintenance

On the MRO/support side of things, Villa said the “FalconScan” system would monitor 100,000 parameters, and will be “directly connected to all aircraft systems, so you quickly know where a failure is and can decide quickly what to do.” Apart from alerts in the cockpit, in-flight notification to engineers on the ground is via FalconBroadcast, he added.

Likewise with the PW812D engines, Cedric Gauthier, director business aviation sales and marketing with P&WC, said the company and Dassault would “have the ability to anticipate problems before they occur.” He added that the new engine was “designed with 10,000 hours on-condition, a 40 percent reduction of on-wing maintenance.”

Technical Briefings

In-depth technical briefings, akin to what will ultimately be contained in the type-rating course, followed at Le Bourget. Gilles Constant, system technical manager for the Falcon 6X, and Mark Aubin, director of Falcon technical support, gave a presentation explaining the flight control system. Aubin said the 6X will be the first business aircraft to have a 115V generator, so electric power can come from the engines, APU or RAT (ram air turbine, which deploys for emergency power). He said, to start the aircraft, the pilot simply turns the APU on, starts it, then starts the left and right engines, “and that’s it, five steps.” The system “auto-configures load-shedding to make the most of what’s left,” he added. While the process is highly automated, “the pilot can still override the automation,” said Aubin. On the support side, he said “We’re working on advanced prognostic algorithm integration and big data.”

Another technical presentation was given by Woody Saland Ph.D., who is based at Teterboro Airport, the headquarters of Dassault Falcon Jet. He stressed that with new Falcons, pilots fly the trajectory. “The sidestick controller is not like on a traditional aircraft; it’s just to influence the flight path.” the FCS works out what had to be done to fly the commands, while making the handling as simple, and ride as comfortable, as possible. Dassault illustrated this with a film comparing steep turns being flown in a Falcon 8X and a Boeing 787, both over Le Bourget, with stark differences in the amount of pilot input and constant correction required. Saland said, “You tell the system, ‘I want to climb [or turn]. You figure it out.'” And the safety angle is covered by having “three different redundant systems from three different manufacturers. Any one of these can fly the aircraft, and if not, you are back to ‘direct law.'” Added to that, there is a priority button on the controller “to kill the other stick,” to avoid situations in which one pilot is unintentionally overriding the inputs of the other, as was the tragic case with Air France flight AF447.

He noted: “Since the Falcon 2000, anyone flying a Falcon is flying the same cockpit,” more or less, so training to transfer is minimized. That said, he noted that with the 6X, the cockpit would be “the biggest we’ve ever had.” He noted that the new EFB is removable “but the idea is that you leave it there, the pilot takes his tablet to the hotel, and wirelessly transfers data [to/from] the airplane.”

The 6X is priced at $47 million, which Dassault claims is no more than the 5X would have been. It is currently negotiating with 5X customers and others to secure the first sales, while it also negotiates new supplier agreements. It expects to produce two aircraft a month beginning in 2023, according to Trappier, “But that depends on how the market is going to react.”