Embraer will face fierce competition in the super-midsize class from Bombardier and Gulfstream when the Legacy 500 enters service in early 2014. But the Brazilians are betting that their newcomer will offer higher levels of technology that will help win them market share.
The Legacy 500, which will be followed in one year by the shorter, 2,300-nm-range Legacy 450, will be the first business aircraft in this class to have three-axis FBW flight controls for elevators, rudder, ailerons and multifunction spoilers. The next least-expensive business jet with three-axis digital flight controls is the $52 million Dassault Falcon 7X. Embraer and Dassault both fit their FBW cockpits with sidestick controllers to increase legroom for the flight crew and provide an uninterrupted view of the instrument panel.
The flight control system will afford full envelope protection, including over speed/Mach, overstress and excessive angle of attack (AOA) limiters. The AOA protection system eliminates the need for a stall warning stick shaker and stick pusher, similar to the system installed in Embraer's E-Jets. The AOA limiter should allow a razor-thin margin to Cl max, thereby resulting in lower V speeds and shorter runway requirements than would be possible if these speeds were referenced to a conventional stall shaker or pusher.
The FBW system also includes a beta, or sideslip, limiter to prevent over-stress of the vertical stabilizer. In case of engine failure, the system also provides pilots with a target sideslip indicator on the primary flight displays (PFD) to help them extract maximum engine-out climb performance in proportion to asymmetric thrust.
Similar to the E-Jets, the FBW system of the Legacy 450/500 has soft limits for pitch and roll that return the aircraft to +30/-15 deg. pitch and +/-33 deg. of bank if the sidestick is released. However, there are no hard limits to pitch and roll if a pilot keeps pressure on the sidestick and stays within the minimum AOA and top speed limits. But the maximum available 30-deg.-per-second roll rate virtually eliminates the temptation.
FBW also offers a smoother ride for passengers because the flight control computers correct aircraft attitude for minor bumps much faster and more precisely than humans can react. The system also reduces pilot workload because the crew only has to make changes to the flight path. Let go of the sidestick and the aircraft will maintain the flight path within flight envelope limits.
FBW also potentially reduces aircraft empty weight because the airframe doesn't have to be overbuilt to provide margins for ham-fisted pilots. In addition, FBW has a stability augmentation function that allows the weight and balance envelope to be expanded so the aircraft can be safely flown with a more aft c.g. This results in reduced trim drag, thereby improving fuel efficiency and range performance.
Four solid-state Goodrich SmartProbe air data/AOA sensors eliminate pitot and static plumbing along with a moving AOA vane. SmartProbes should slash the cost of pitot/static/AOA system maintenance by a factor of seven.
Rockwell Collins is supplying its Pro Line Fusion equipment for the Legacy 450/500, one of the latest avionics designs. The two Embraers feature four 15-in. landscape configuration flat-panel displays with standard synthetic vision, dual FMS and electronic charts. The base package also includes a hybrid TCAS/Mode S traffic surveillance system, Class A TAWS, solid-state weather radar with Doppler turbulence detection and dual comm/nav/surveillance radios.
Most optional equipment will be certified after the aircraft enters service. Options include HUD and EVS, VNAV, auto-throttles, WAAS LPV, RNP 0.3 and dual IFIS file servers for paperless chart operations, plus required time of arrival, 4-D nav and takeoff and landing distance computer for the FMS. Rockwell Collins MultiScan weather radar, ADS-B OUT, predictive wind-shear and XM satellite radio or XM data link weather also will be offered at extra cost, along with Link 2000+ CPDLC for Europe, single or dual HF transceivers and VHF data link for ACARS.