Dassault Unveils Falcon 5X

By Fred George fred_george@aviationweek.com
Source: Business & Commercial Aviation

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.

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