Bigger is better in the booming large-cabin business aircraft segment. Just look at the 200+ orders Gulfstream has for its G650 uber-jet, an aircraft with the largest cabin cross-section of any purpose-built jet in current production.

Dassault Aviation, though, set an even larger cabin size standard when it introduced its $45 million, 5,200-nm range Falcon 5X at the 2013 NBAA Convention. Compared to the G650, the Falcon 5X has 1 in. more headroom, 2 in. more floor width and equal maximum internal width. Those measurements allow Dassault to claim it will offer the most generous cabin cross-section in a purpose-built business jet when the Falcon 5X enters service in 2017.

The 5X will be the first clean-sheet Falcon Jet in a decade. The airframe shares little in common with the Falcon 7X that entered service in 2007, having a new fuselage, new wing, new engines and new digital flight control system functionality.

The G650's cabin is longer than that of the Falcon 5X, so the big Gulfstream offers 21% more overall interior volume. That's an essential design provision because Gulfstream's flagship has 3 hr. more endurance than the new Falcon Jet, virtually necessitating a forward crew rest area nestled ahead of the front galley. The Falcon 5X will have 1,770 cu. ft. of net cabin volume available for use by passengers, a little less than the G650 with a crew rest compartment but 220 cu. ft. more than the Falcon 7X trijet, currently Dassault's largest aircraft.

But the Falcon 5X isn't intended to compete against the Gulfstream G650 or replace the Falcon 7X. Instead, the French are taking aim at Gulfstream's aging 4,250-nm range G450 and Bombardier's fuel thirsty 5,500-nm range Global 5000. The Falcon 5X will have a considerably larger cabin than either of those heavy-iron competitors, yet it will weigh less and its wing will have better lift-to-drag characteristics. It also will be fitted with new technology Snecma engines than are 10-15% more fuel efficient than current engines having similar thrust output.

The Falcon 5X's more fuel-efficient engines, combined with its lower weight and advanced wing lift-to-drag characteristics should slash fuel consumption by one-third on average compared to competitive aircraft. Dassault also claims the Falcon 5X will have a direct operating cost 30% lower than the G450's and 35% less than that of the Global 5000.

The new Falcon wasn't always to be as large or as long-legged as the final iteration. When Dassault launched initial Falcon SMS (for “super midsize”) design studies in 2006, it was intended to compete against the then hot-selling Bombardier Challenger 300, as well as the Gulfstream G250 (now G280) and Embraer Legacy 600 in the super-midsize segment.

But when world financial markets tanked in 2008, demand fizzled for SMS and smaller aircraft. Soon, it became apparent that those markets, and particularly the lighter jets, might not fully recover for a decade or more. The large-cabin market, however, began to rebound as soon as the first green shoots of economic recovery sprouted in 2009.

So, Dassault engineers went back to their CATIA screens and completely revamped the SMS design. By the end of 2009, the SMS had become a much different aircraft. Indeed, it would become the largest and most-advanced Falcon Jet yet built, requiring an investment of well over $1 billion. As such, the Falcon 5X will provide the basis for larger and longer range Falcon Jets into the future.

Dassault’s Most Commodious Cabin Yet

The Falcon 5X's circular fuselage has a diameter that is 8 in. larger than any previous Falcon Jet. Overall cabin length only is 5 in. shorter than that of the Falcon 7X, thus the Falcon 5X's cabin volume is 14% greater than that of its trijet sibling. The increased cross section affords 4 in. more headroom and 10 in. more floor width than the Falcon 7X, thereby allowing the use of wider seats while still increasing available aisle width by 5 to 6 in. in most areas of the cabin. Noise will be sopped up by an acoustical insulation package similar to that used aboard the Falcon 7X, assuring interior noise levels at or below those of any current production Falcon Jet.

Similar to most other long-range, large-cabin business aircraft, the heart of the cabin is divided into three sections. The 25.3-ft.-long main seating area has a forward, four-chair club section, a mid-cabin four-seat conference grouping flanked by a credenza with occasional bench seating and a separate aft lounge that can be configured several ways, including with two three-place divans. The three lounges will berth six passengers on overnight missions.

Up front, there's a 7-ft.-long vestibule with crew lavatory, galley and storage that is longer and has about 25% more volume than the vestibule of the Falcon 7X. The galley area also is considerably larger than those of the G450 and Global 5000. The galley has more usable storage space and better ergonomics than the one in the Falcon 7X.

Overhead in the vestibule is business aviation's first large skylight (the HondaJet has a pair of small skylights in its lav) because there's almost never too much ambient light available in the galley area. When the sun is too bright, electro-chromic filters will dim the skylight, as well as all cabin side windows.

As there is 5 in. more floor width in the galley area and the cabinetry has gentle convex curves, passengers won't feel as though they're squeezing through a tunnel as they walk through the forward vestibule area. The galley was designed with extensive input from flight attendants who work aboard current generation Falcon Jets.

Dassault customers said they wanted more ambient light in the cabin, so the Falcon 5X will be fitted with 28 of the largest cabin windows ever used on a Falcon Jet. They're 1 in. taller than the transparencies used on the Falcon 7X. They indeed provide as much window area per cubic foot of cabin volume as the 16 wide oval cabin windows of the G650, so no business aircraft will have more ambient light.

The cabin has several new design features. The chairs, for example, have a more contemporary look with hollowed out armrests and cocoon-like, wraparound seat bases and backs. The cocoon chairs make passengers feel as though they occupy a space that's dedicated solely to them, not unlike belting into the front seat of a luxury automobile. The side rails are split-level affairs. The foldout worktables extend so that the top surfaces are flush with the side rail upper ledges, effectively increasing their usable width to the cabin sidewalls.

On the lower sidewall step, there are storage pockets that are level with the outboard armrests of the passenger chairs. Sliding lids above the storage pockets reveal spaces to stow and plug in iPhones, iPods or PDAs. Each individual chair also has ergonomic cabin management controls with hard line select keys for frequently used functions, plus touch screen controls and a rotating knob for adjusting variables. There are plug-in ports for individual seat monitors and Wi-Fi will support using iPads or iPhones as IFE monitors. Broadband Internet connectivity will be provided by satcom and also perhaps by air-to-ground data links. It's likely that the aircraft also will have an Iridium phone, but Dassault hadn't yet released the initial specifications and description document as we closed this issue.

The mid-cabin section has the feel of an informal conference room. There are four conventional chairs arranged around a conference table, plus a credenza on the opposite side that has a long bench cushion that provides a perch for other passengers to join the conversation with those at the table.

The aft section of the cabin may configured as a private stateroom, with selective electro-chromic filters that transform bulkhead partitions into privacy curtains. Some operators may choose to fit the aft area with a single workstation chair and a pull-out divan on the opposite side. Others may opt for one divan on the left and another on the right. Still others may elect to fit one side with a pair of facing chairs and a divan on the opposite side — or any combination of those modules.

The aft lavatory is shorter than the one in the Falcon 7X, but it's actually quite roomy because of the larger cross-section. In addition, the fuselage doesn't begin to taper until aft of the internal baggage door. The lav features a vacuum toilet, vanity with hot and cold running water, and generous storage. Notably, the forward and aft lavs do not share common water and waste systems. The forward lav is available with either a conventional chemical or vacuum toilet and is not linked to the aft lavatory.

The 155-cu.-ft. aft baggage com–partment will be accessible in flight with no altitude restrictions because the engine rotor burst plane is behind the aft pressure bulkhead. The external access door translates aft of the doorway when opened so that it doesn't obstruct the opening. There is a ladder that will ease luggage loading chores for the crew.

Conventional Structure, Advanced Systems

Construction of 5X components is well underway at Dassault and its subcontractors. No surprises here. Similar to all previous Falcon Jets, Dassault will use high strength aluminum alloys for most of the primary airframe structure of the Falcon 5X. Most of the parts will be joined with conventional hardware. A few components will be fused together using friction stir welding, a first for a Falcon Jet. Composites will be used for the empennage, engine nacelles, fairings and radome, among other secondary structures.

Work share is similar to that on the Falcon 7X, with Dassault building the forward and aft fuselages, plus the wings; Daher-Socata is constructing most center fuselage parts; and Fokker is making the composite empennage with extensive use of resin transfer molding. In addition, Belgium's SABCA is building the aft, lower center fuselage section; GKN is constructing the wing's aft control surfaces; Safran's Snecma supplies the nacelles as part of the integrated powerplant package; Corsica's Corse Composite Aeronautique is building the wing to body fairing; and Potez, in southwest France, is supplying the main entry door.

The aero loft contours depart from those of previous Falcon Jets, starting with the 779-sq.-ft. clean-sheet wing, the first Dassault airfoil to have winglets as part of the initial design. It features a straight leading edge, a relatively modest 33 deg. of leading edge sweep and a 5% to 10% better lift-to-drag ratio than the airfoil of the Falcon 7X. High-altitude Mach buffet boundaries should be at least 15% better than those of legacy large-cabin Falcon Jets. And the wing weighs 500 lb. less than that of the Falcon 7X because of improved structural efficiency, in part due to the wing's straight leading edge that makes possible a wider chord, more rigid internal wing box.

The signature cruciform Falcon Jet tail design is retained, but the horizontal stabilizer has no anhedral.

The nose has completely new loft contours, including cockpit windows that are 32% larger than those of the Falcon 7X. This will make it much easier to see over the nose during takeoff, approach and landing. The flight deck is considerably more comfortable, including increased headroom and sufficient room aft of the pilot chairs to recline either one to 130 deg. for short crew rest breaks.

There's also a new jump seat for a third crewmember that stows full size behind the right pilot seat. It slides laterally into position in the center aisle and it pivots and reclines for greater comfort — a welcome replacement for the origami-like folding jump seat of older Falcon Jets.

The 5X will be the first Falcon to have a primarily AC electrical system, one with starter-generators that will produce 115/200 VAC, three-phase, variable frequency power. AC power, supplied by either the APU or GPU, also will be used to start the main engines, a departure from the air turbine starters and DC starter-generators used on legacy Falcon Jets. AC power will also be used for high electrical loads, including windshield and probe anti-ice heating along with cabin management and IFE systems. Two 35 AH sealed lead-acid batteries will anchor the DC electrical system, used for critical power functions such as the digital flight control system (fly by wire). Transformer rectifiers will convert AC to DC. The overhead electrical control panel has been simplified and the electrical system has enhanced automatic bus tie functioning to protect it in the event of malfunctions.

The dual-redundant 3,000-psi hydraulic systems are simpler than the triple-redundant systems of the Falcon 7X. Four engine-driven pumps supply System A and System B hydraulic circuits, each one having left and right engine-driven pumps. System B also has a DC standby pump. Systems A and B also have electrically powered, backup subsystems that power some of the flight control actuators in the event of dual failure of the normal hydraulic system. MIL-H-5606 is retained as the standard for hydraulic fluid.

The fuel system is vintage Falcon Jet, having pressurized tanks and dual-redundant fuel boost pumps.

Heroux Devtek will supply the landing gear, with soft landing touchdown assured by trailing link main gear and a dual chamber olio nose gear. The steer-by-wire system will be controlled through the digital flight control system. Notably, the nose gear doors will be closed when the gear are fully retracted or extended, greatly reducing cockpit noise during landing approach. Meggitt will furnish the dual-channel brake-by-wire system with high-energy carbon heat packs. Remote tire pressure monitoring and brake temperature indicating systems will be optional.

If the air-conditioning and pressurization system follows the 7X design, there will be a second emergency “pack” having only heat exchangers, but no turbine, compressor and fan.

Similar to legacy Falcon Jets, the Falcon 5X will have a single air-cycle machine pack. It's supplied by Liebherr. There will be separate temperature controls for the cockpit, galley, and forward and aft cabin. The Falcon 7X only has a three-zone system.

The 9.9-psid pressurization system will provide a 3,900-ft. cabin altitude at FL 410 and a 6,000-ft. cabin at FL 510. On most long-distance flights, cabin altitude won't exceed 5,000 ft. because the aircraft normally cruises at or below FL 450.

The digital flight control system, designed and built by Dassault, is based upon the Falcon 7X architecture, but it will integrate more functions. In addition to carefree handling, flight path stability and envelope protection, the fly-by-wire (FBW) system will host control of mid-span flaperons that can function as ailerons, flaps and/or spoilers.

The cockpit will have left and right sidestick controls; three main or primary, dual-channel flight control computers that host normal, alternate and direct law functions; plus three backup, or secondary, single-channel flight control computers that only host direct law functions, including yaw damper. Unlike the Falcon 7X, the Falcon 5X won't be fitted with an analog emergency computer used for temporary control to be used only in the event that all six main and backup flight control computers fail. But the aircraft can be dispatched after any single electronics failure.

Most primary and secondary flight control surfaces will be hydraulically powered. But in a departure from the Falcon 7X, the trailing edge flaps will be electrically powered rather than hydraulically actuated. Use of flaperons is a first aboard a business jet. When the crew selects speed brakes 1, for instance, the outboard ailerons will deflect up while the mid-span flaperons will move down, thereby increasing drag while minimizing wing bending moment. The flight control surface geometry also virtually eliminates turbulence over the horizontal tail that's felt as airframe buffet. The new function especially will be appreciated by passengers when the aircraft is descending with bleed air anti-ice on. Engine power must be increased for adequate bleed air supply. During descents, the speed brakes on older Falcons had to be used to control speed with anti-ice on. That should no longer be necessary with the split aileron/flaperon function.

The 5X has conventional air brake panels, but they only begin to deploy when speed brakes 2 is selected.

The split aileron/flaperon geometry, along with the aircraft's full-span leading edge slats, will be key to enabling Dassault to earn steep approach certification for the 5X, enabling it to use London City Airport.

Bleed air will be used for wing leading edge and engine inlet anti-ice heating. Unlike previous Falcon Jets, pilots will be able to select wing anti-ice while on the ground. It automatically will activate with weight off wheels. UTC Hamilton Sundstrand in San Diego will furnish the ground-use-only APU.

Balancing Act

Falcon Jets are known for their class leading fuel efficiency and the Falcon 5X will be no exception. No other large-cabin aircraft, except for Dassault's own Falcon 2000S and 2000LXS, should squeeze more miles out of a pound of jet fuel on equal length trips.

One reason is the Falcon 5X's Mach 0.80 design cruise speed, which is relatively placid by current standards. Some large-cabin business aircraft makers now tout cruise speeds of 0.85 to 0.90 Mach, shaving as much as an hour off of longer trips.

The Falcon 5X easily can speed up to 0.85 Mach, but doing so increases fuel consumption by close to 9% and shortens max range by 450 mi. Dassault's market research, though, indicates that the most likely Falcon 5X buyers will value cabin comfort, range and price above the need for speed.

Having 5,200 nm of range at 0.80 Mach, the Falcon 5X will be able to fly eight passengers from London to Tokyo, Beijing to Minneapolis or New York to Tel Aviv in 11 hr. 30 min. At 0.85 Mach, it will be able to fly from London to Houston, Detroit to Moscow or São Paulo to Lisbon in under 10 hr.

Glance please at the accompanying specifications box. The Falcon 5X will have a favorable power-to-weight ratio and relatively low wing loading for a large-cabin aircraft with slats. It should offer virtually the best takeoff field length performance of any aircraft capable of flying 5,200 nm.

Dassault is striving to make the 5X its most reliable and most maintainable business jet yet. It will be fully MSG-3-compliant and scheduled maintenance will come at 800-hr. or 12-month intervals. Custom-tailored maintenance programs will be offered to operators.

Extensive high-stress, high-cycle testing of components and systems should minimize growing pains associated with early serial number airplanes. Dassault also is developing a new onboard maintenance monitoring system that will watch up to 10,000 parameters, not unlike the orange flight test boxes bolted into the aircraft for development work. Aircraft health signs and symptoms will be broadcast back to Dassault in real time for analysis. Warranty coverage will be more extensive than with previous Falcon Jets.

Performance and efficiency numbers notwithstanding, the Falcon 5X's trump card is cabin size. No other purpose-built business jet priced less than $55 million equals it.

The Falcon 5X is the most technically advanced civil jet from Dassault, but all of its new systems have been wrung out on other aircraft. Almost nothing on the aircraft is “bleeding edge” technology that might risk the aircraft's spending excessive time in the hangar. Wild frequency AC electrical systems have been used on business aircraft for more than 15 years. The Falcon 7X pioneered the use of digital flight controls on board a purpose-built business aircraft six years ago. The hydraulic system is a basic dual-redundant design with two extra subsystems to provide triple-redundant hydraulic power for the flight control actuators.

Most notably, the Falcon 5X provides a clean-sheet foundation for larger and longer range Falcon Jets, ones that will compete directly against the newest de–signs being developed by Bombardier and Gulfstream. As such, the Falcon 5X isn't just the latest business aircraft to be announced by Dassault, it's also a milestone in the history of the company. It also marks the end of the trijet era at Dassault and the beginning of a whole new line of twin-engine large-cabin aircraft from the French firm that will be more comfortable, more capable and more cost-effective to operate. Construction of the first flight test aircraft is well underway. First flight is slated for the first half of 2015.

Tap herein the digital edition of B&CA

for an interactive look at the Falcon 5X's features, or go to AviationWeek.com/falcon5x

Dassault Falcon 5X Preliminary Specifications
B&CA Equipped Price $45,000,000
 
Characteristics
  Wing Loading 89.3
  Power Loading 3.04
  Noise (EPNdB) NA
 
Seating 3+8/19
 
Dimensions (ft./m)
External
  Length 82.6/25.2
  Height 24.5/7.5
  Span 85.1/25.9
Internal
  Length 44.0/13.4
  Height 6.3/1.9
  Width (Maximum) 8.2/2.5
  Width (Floor) 6.8/2.1
 
Thrust
  Engine 2 Snecma Silvercrest
  Output/Flat RatingOAT°C 11,450 lb. ea./ISA+15C
  TBO OC
 
Weights (lb./kg)
  Max Ramp 69,800/31,661
  Max Takeoff 69,600/31,570
  Max Landing 66,100/29,983
  Zero Fuel 43,500/19,731
  BOW 38,170/17,314
  Max Payload 5,330/2,418
  Useful Load 31,630/14,347
  Executive Payload 1,600/726
  Max Fuel 28,200/12,791
  Payload With Max Fuel 3,430/1,556
  Fuel With Max Payload 26,300/11,930
  Fuel With Executive Payload 30,030/13,622
 
Limits
  Mmo 0.900
  FL/Vmo FL 270/370
  PSI 9.9
 
Climb
  Time to FL 370 NA
  FAR Part 25 OEI Rate NA
  FAR Part 25 OEI Gradient NA
 
Ceilings (ft./m)
  Certificated   51,000/15,545
  All-Engine Service ≥41,000/≥12,497
  Engine-Out Service NA
  Sea-Level Cabin NA
 
Certification  
  FAR/EASA Part 25 Scheduled for 2017