Re: Now Boarding ... Chicken or Beef?
When I did the B738 sim to set the required thrust all I needed to do was to set both levers to 60%. On the display each throttle or thrust position is shown as a circular bar graph, I s'pose you'd call it. A 2nd circular bar graph would then rise up to match it, presumably that aircraft's version of FADEC setting the demand for each engine to match the manual setpoint (thrust lever position).
One part of the display is showing the commanded thrust, and the other the actual thrust. We only occasionally use the command part of the display (on the ground setting the initial 30%). After that you tend to just push or pull the levers for effect, not specifically looking for a power number, but just making the speed trend vector 'go away'. Of course, in the 380, it's almost always autothrust.
In manual thrust, basically the same. In auto, the levers are left in a gate, and don't move with thrust changes.
On another note, often "yaw damper" is mentioned. I looked it up on Wiki but its description is fairly brief so I couldn't really understand how it works or how it's applied. Do you know any links where I can get a better description of it? Or can you explain it better?
Look up Dutch roll. The yaw damper is there to counter that....
Finally, when discussing "alternate law", I presume that it's a mode of control that Airbus uses. Why the term "law" in this regard?
The FBW system is written to obey a set of rules. So calling them 'laws' is as good a term as any. Depending upon the health of the system, it may operate in NORMAL law, ALTERNATE law I, ALTERNATE law II or DIRECT law. In normal law, the flight control computers interpret your control inputs to give you a result. You don't really care which controls are used, or how it does it. If you place the aircraft in a 10 degree bank, it will stay there. Protections exist for bank and pitch limits, overspeed, g limits, angle of attack (i.e. stall). As the system degrades, it might fall back to ALTERNATE I, where most of the protections have disappeared, but the automatics are still available. ALTERNATE II is a bit further down this road, but this time, no automatics are available (flight director, autopilot, auto thrust). In DIRECT law, the controls simply move in concert with any control input. No automatics are available, but the basic flight behaviour is as per a non FBW aircraft (i.e. 747 or 767).