Falcon 2000S

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

The Falcon 2000S retains the 28 VDC electrical architecture of the Falcon Jet family with both main and essential buses. Left and right sides of the system normally are split for fault isolation and manually switched together when needed. There is no automatic bus tie. Power is supplied by two engine-driven brushless generators, two lead-acid batteries and an APU, rated for both ground and flight operation up to 35,000 ft. External power can be supplied by a ground power unit.

The left wing, half the center wing box and aft fuselage tanks are grouped together and feed the left engine. The right wing, half the center wing box and the forward fuselage tanks form the other side feeding the right engine. The DX and S have identical fuel tanks. Total fuel capacity is 14,600 lb., with fuel contained in left and right wing, fore and aft center wing and fore and aft fuselage tanks. Compared to the LX and LXS, the S has shorter fore and aft belly tanks that reduce fuel quantity by 2,060 lb. The left- and right-side fuel systems have almost the same fuel capacity, with the latter holding 64 lb. more and most of that typically is consumed by the APU prior to engine start.

Dual left and right brushless DC fuel boost pumps, housed in quick-change dry sump canisters, supply the engines and APU. After engine start, the bleed air system pressurizes the fuel tanks. If a boost pump fails, this maintains positive head pressure to feed the engine-driven fuel pumps, even at full takeoff power.

The left- and right-side 3,000-psi hydraulic systems, each having two pumps and using MIL-H-5606 red fluid, power the flight control actuators, leading-edge slats, trailing-edge flaps and wheel brakes, along with the nosewheel steering, landing gear and gear doors, plus airbrakes and thrust reversers. One of the pumps in the right-side system is electrically powered and can provide power to essential hydraulic equipment if all three engine-driven pumps are inoperative. The four main wheel brakes are fitted with carbon heat packs. Dassault originally planned for an optional auto-brake system, but the final runway V speeds were so low that engineers deemed it unnecessary.

The primary flight controls are fully hydraulically powered in all three axes. There is an indicated speed-proportionate artificial control feel (Arthur Q) system for roll. Position of the horizontal stabilizer varies the amount of control feel force in pitch. The result is a nearly constant stick force per g of vertical acceleration. The rudder has a simple spring box for artificial feel.

The control surfaces have no trim tabs. Electro servos also reposition the neutral points of the aileron and rudder artificial control feel units to provide trim in those axes.

Dual electric trim motors reposition the movable horizontal stabilizer for pitch trim. There is an automatic Mach trim that increases speed stability between Mach 0.77 and Mach 0.87. The stab range of motion has been recalibrated from +2 deg./-10 deg. to +1 deg./-11 deg. to provide increased nose-up pitch control authority to counter the effect of the winglets and new high-lift system.

The slats and three-position flaps work together as high-lift devices. On Falcon Jets, the full-span slats provide most of the slow speed lift augmentation. The S is also equipped with the Falcon 900LX's three-position trailing edge flaps, along with other high-lift design features. When compared to older Falcon 2000 aircraft with partial-span slats, the full-span slats increase stalling angle of attack (AOA) by as much as 4 deg., thereby cutting stall speed by as much as 8 kt.

The slats also function as automatic stall protection devices at high AOA. If the aircraft is in the clean configuration, the outboard slats extend at high AOA to enhance roll control characteristics by energizing the boundary layer over the wing with a high velocity air stream. If the slats are extended, the inboard slats retract as AOA approaches stall to produce a positive stall break while maintaining full roll control.

Comments On Articles