Fly-by-wire systems replace the traditional connection of aircraft control surfaces by a series of pulleys and wire with and electronic interface where movement of the flight controls is converted into electronic signals which are transmitted to actuators which move the control surfaces. A fly-by-wire system can also send computer generated signals to these actuators commanding control surface movements without any input from the pilot. These systems are designed to automatically stabilize the aircraft. Since the inception of fly-by-wire technology there has been an ongoing debate about how much pilot input should be allowed versus how much computer generated hard and fast limits should be placed on pilot inputs. For the moment no consensus has arisen, and the two major aircraft manufacturers continue to champion their system over their competitors. Boeing has decided that the pilot’s judgment is paramount while Airbus has decided that hard limits on the aircraft flight envelope are best controlled by a computer. There are 3 primary concerns with the flight envelope of jet aircraft, those being over speeding, stalling and over-banking. Boeing aircraft utilize EICAS (Engine Indicating and Crew Alerting System) provides crews with aircraft engine and system instrumentation and crew annunciations, as well as a checklist for performing remedial actions while Airbus calls their system ECAM (Electronic Centralized Aircraft Monitor) which, in addition to the features of EICAS, also provides recommended remedial action. The Airbus fly-by-wire system has hard limits on the aircraft flight envelope which prevents the aircraft from over speeding, stalling or over banking. It also has an auto-thrust system which automatically spools up the engines and limits pitch angle to prevent stalls and optimize climb performance. Boeing, on the other hand, provides a loud warning sound that the aircraft is approaching or in a potential unsafe condition along with an auto-throttle system which provides a tactile cue to pilots through the control wheel without the pilot having to refer to the EICAS. Please leave a comment and let me know that, as a pilot, which system would you feel more comfortable with? Until next time keep your wings straight and level Hersch! JetAviator7 ps: Don't forget to sign up for our newsletter "All Things Aviation" here!
by John M. White •