@ slasher
the airbus fbw is not a CWS.
From what I read here and what I hear on the cockpits, very few airbus pilots really know what is the nature of airbus fbw.
Boeings, fbw or not, behave conventionally in the sense that they are speed stable (they tend to maintain the angle of attack due to their static longitudinal stability even when stick free). To manoeuvre a boeing you need to exert forces in the stick, which produce g forces prpportional to the stick forces, thus changing path. This is achieved by making the elevators deflection directly related to stick deflection. Stick Force is what matters, however. You need to feel the force, even if the flight control system is hydraulically powered. The flight control system gives feedback to the pilot by means of stick forces. When you trim the stick force, the airplane will tend to maintain the angle of attack, at the expense of flight path which means you will slightly oscillate in altitude and pitch maintaining the trim speed and only need few and small inputs to maintain flight path.
Airbus fbws behave differently. They are path stable, which means that they tend to keep the trayectory even at the expense of speed and angle of attack, as if they had a different form of longitudinal stability. the airplane will oscillate in speed and even pitch maintaining flight path. In the bus, we achieve the g forces for manoeuvring by deflecting the stick. g force is proportional to stick deflection, not to stick force. The feedbackis not given to the pilot, but to computers. You can't really speak of stick-free in an A320. they are never stickfree. Stick free means "tend to maintain trayectory". Thereore forces in the stick are not necessary. Trim is not necessary at all. There is a THS, and there is "autotrim", but in fact the A320 is a trimless airplane. In the THS jam or dual hydraulic blue remaining ALTN LAW keeps autotrim with elevators alone.
All airplanes are manoeuvred in by inducing g forces. You want the nose up, you pull the stick. You want the nose down: you push the stick. When you achieve the desired flight path we want the airplane to be stable and tend to maintain it. You will only need a few smalls input to maintain the flight path precisely. Forces in boeings, deflections in airbuses.
In the fbws we don't have to trim. That is all the difference. No resemblance to a CWS nor an autopilot.
When pilots say that to "really fly" the A320 you have to disconnect computers to bring the DIRECT LAW... I feel sick because I know they don't know very much about flight controls and flight at all... No airplane could be certified that had a fbw direct law system with no stick forces.