Bigger is better in the booming large-cabin business aircraft segment, and the debut of Dassault’s $45 million Falcon 5X is the biggest news at this year’s National Business Aviation Association Convention.

Formerly known as the Falcon SMS, this newest member of the family will have a cabin cross section that’s slightly larger than that of Gulfstream’s G650 uber-jet, but it is considerably shorter, in keeping with its 5,200-nm maximum range at Mach 0.80. The aircraft will cruise comfortably at Mach 0.85, but then range decreases to 4,750 nm.

The 5X is the first clean-sheet Falcon in a decade. It shares little with the 7X that entered service in 2007, having a new fuselage, new wing, new Safran Snecma Silvercrest turbofans and new digital flight control system functionality.

The new Falcon will compete head-on with Gulfstream’s 4,200-nm range but aging G450, and with Bombardier’s 5,400 nm-range but fuel-thirsty Global 5000. But its considerably lighter empty weight, more advanced aerodynamics and 10-15% more fuel-efficient engines will cut fuel consumption by up to one-third compared to those competitors. Dassault claims that the 5X will have 30% lower direct operating costs than the G450’s and 35% less than the Global 5000’s.

The 5X wasn’t always as large or as long-legged as it is today. When Dassault launched initial SMS design studies in 2006, it was intended to compete against Bombardier’s then hot-selling Challenger 300, Gulfstream’s G250 (now G280) and Embraer’s Legacy 600. But when world financial markets tanked in 2008, demand imploded for SMS and smaller aircraft.

However, the large-cabin market began to rebound as the first green shoots of economic recovery sprouted in 2009, so Dassault’s engineers went back to their CATIA screens and completely revamped the SMS. It has become a very different aircraft, the largest and most advanced Falcon yet built, and will provide the basis for larger and longer range Falcons in the future. Expect another member of the new family to be announced before EBACE 2014.

The 5X’s circular fuselage is 8 in. greater in diameter than any previous Falcon’s. Thus, while overall cabin length is 5 in. shorter than the 7X’s, its volume is 14% greater, with 4 in. more headroom and 10 in. more floor width. The main 25.3-ft.-long salon is divided into three: a forward, four-chair club section, a mid-cabin four-seat conference grouping and a separate aft lounge that will accommodate six passengers in full flat berths on overnight missions. Cabin altitude will be 3,900 ft. at FL 410 and 6,000 ft. at FL 510.

The cabin has several new design features. The seats have hollowed-out armrests and cocoon-like, wraparound bases and backs to make passengers feel as though they occupy a space that’s dedicated solely to them. There are plug-in ports for individual seat monitors, and Wi-Fi will support using iPads or iPhones as IFE monitors.

Dassault customers said they wanted more ambient light in the cabin, so the 5X will be fitted with 28 of the largest cabin windows ever used on a Falcon. They’re 1 in. taller than those on the 7X and provide as much window area per cubic foot of cabin volume as the 16 wide-oval cabin windows of the G650.

The 155-cu.-ft. aft baggage compartment will be accessible in flight with no altitude restrictions because the engine rotor burst plane is behind the aft pressure bulkhead. There will also be an unpressurized baggage compartment in the tail.

The Falcon 5X’s airframe and systems introduce no unproven technologies, so early serial number buyers aren’t likely to suffer major growing pains. The primary airframe is a semi-monocoque aluminum structure, with composites for the empennage, fairings, nacelles and other secondary structures.

The clean-sheet 779-sq.-ft. wing is Dassault’s first 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 5-10% better lift/drag ratio than the 7X’s. The Falcon’s signature cruciform tail 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, making it much easier to see over the nose during takeoff, approach and landing. The flight deck is considerably more comfortable, with increased headroom and space aft of the pilots’ seats to recline either one to 130 deg. for short rest breaks. There’s also a new jump seat for a third crewmember that stows behind the right pilot’s seat.

Systems are thoroughly updated. The 5X will be the first Falcon to have a primarily AC electrical system, with 115 VAC variable-frequency starter-generators, eliminating the need for air turbine or DC motor starters. There will be only two main 3,000-psi hydraulic systems, each with a subsystem and electric power pack to provide redundancy for the flight control actuators. The fuel system is vintage Falcon, having pressurized tanks and dual-redundant fuel boost pumps.

The Dassault-designed digital flight control system is based upon Falcon 7X architecture, but it will integrate more functions, including business aviation’s first flaperons, combining flap, roll spoiler and airbrake functions in a single control surface. The cockpit will have left and right sidestick controls linked to three primary and three secondary flight control computers. While most flight control surfaces will be hydraulically powered, the trailing edge flaps will be electrically powered, a departure from the 7X.

Falcons are known for their class-leading fuel efficiency and the 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 5X’s Mach 0.80 design cruise speed, relatively placid by current standards. While some large-cabin business aircraft makers now tout cruise speeds of Mach 0.85 to 0.90, shaving as much as an hour off of longer trips, Dassault’s market research indicates that longtime Falcon operators value cabin comfort, range and price above the need for speed.

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

Dassault is striving to make the 5X the most reliable and most maintainable business jet that it has ever built. Scheduled maintenance will come at 800-hr. or 12-month intervals. Custom-tailored maintenance programs will be offered.

The 5X provides a clean-sheet foundation for larger and longer range Falcon Jets, ones that will compete directly against the newest and most capable designs being developed by Bombardier and Gulfstream. As such, it isn’t just Dassault’s latest jet. It is a milestone in the company’s history, the end of its trijet era and the beginning of a whole new line of twin-engine, large-cabin aircraft that will be more comfortable, more capable and more cost-effective.

Construction of the first flight test aircraft is well under way. First flight is slated for the first half 2015. Look for a full report in the November 2013 issue of Business & Commercial Aviation.

Click here to see photos of the Falcon 5X on our Things With Wings blog.