Fly-by-Wire: Digital Flight Controls Move from Airliners to Jets
In a fly-by-wire aircraft, the pilot's inputs go to computers rather than cables. The Falcon 7X brought the idea to business jets in 2007, and it now defines most new large-cabin designs.
In a conventional aircraft, moving the control column pulls cables and pushrods that run back to the control surfaces, often through hydraulic boosters. In a fly-by-wire aircraft, the pilot's hand sends an electrical signal to a set of computers, and the computers decide how to move the surfaces. The idea came from fighters and airliners. Over the past two decades it has become the defining technology of new large business jets.
What it is
A fly-by-wire system has three main parts. Sensors measure the pilot's inputs and the aircraft's motion. Flight control computers, usually duplicated or triplicated so that one failure does not matter, calculate the required response. Electric or electro-hydraulic actuators then move the ailerons, elevators, rudder and spoilers.
Because a computer sits between pilot and surfaces, it can do more than relay commands. The most important extra is flight envelope protection: the software will not let the aircraft stall, overspeed or bank too steeply, however hard the pilot pulls. Systems run under different "laws". Normal law includes full protection; if sensors or computers fail, the system falls back to alternate law with fewer protections, and in the last resort to direct law, which passes the pilot's commands straight to the surfaces.
From fighters to airliners
Concorde used an analogue form of fly-by-wire from 1976. The breakthrough for airliners was the Airbus A320, which entered service in 1988 as the first mass-produced airliner with digital fly-by-wire controls and small sidesticks instead of a control column. Boeing adopted the technology on the 777, which first flew in 1994, keeping a traditional yoke and allowing pilots to override the protections, a philosophical difference that still separates the two makers.
Business jets follow
Dassault brought fly-by-wire to business aviation with the Falcon 7X. It first flew on 5 May 2005, was certified by EASA and the FAA on 27 April 2007 and entered service that June as the first business jet with fully digital flight controls. The Falcon 8X, Falcon 6X and the new Falcon 10X continue the approach; Dassault says the 10X adds a "Smart Throttle" linked to both engines and a protection mode derived from the Rafale fighter.
Gulfstream's G650, certified by the FAA on 7 September 2012, was the second fly-by-wire business jet. The G500 and G600 went further with active control sidesticks, which are electronically linked so each pilot feels what the other is doing. The G700, certified on 29 March 2024, and the G800, certified in April 2025, share that design, as does the G400.
Embraer took the technology down a size. The Legacy 500, certified by the FAA on 21 October 2014, was the first midsize business jet with fly-by-wire and a flat-floor stand-up cabin. The Legacy 450 followed in 2015, and both evolved into the Praetor 600 and Praetor 500 in 2019. Bombardier's Global 7500, certified by Transport Canada on 28 September 2018, uses a fly-by-wire architecture based on the airliner now called the Airbus A220, with active load alleviation to reduce the effect of turbulence. The Global 8000 inherits it.
VIP versions of airliners bring the technology with them: every Airbus corporate jet, from the ACJ318 to the ACJ350, and the Boeing BBJ 787 are fly-by-wire. The BBJ versions of the 737 are not.
Benefits, limits and what comes next
Fly-by-wire saves weight by removing cables and pulleys, and it lets engineers make an aircraft handle the same way across its speed range. Protections reduce the risk of loss of control, the leading category of fatal accidents in many aviation safety studies. Load alleviation gives passengers a smoother ride, and a family of aircraft can share control software, which shortens pilot training between models.
The costs are high. The software must be certified to the strictest standards, the hardware needs multiple backups and independent power, and the development cost is hard to recover on a small, inexpensive jet. That is why no light jet in the JetAtlas catalogue uses full fly-by-wire. As each new large-cabin design arrives, the technology spreads a little further. Whether it reaches the light-jet class depends on cheaper computers and actuators, and on a manufacturer willing to pay for the certification first.