The EEC is, through its sensors, able to calculate what the thrust lever angle should be according to the temperature in order not to exceed any engine limits or max thrust according to above. This calculation output is presented to the pilot as the "Reference N1 bugs" on the primary engine indications display.
Thanks this is where I had some conflicting information. The first few pages of the FCOM chapter 7 (Engines) you find A/T LIM displayed in a white box on the Thrust Mode Display. The definition of FCOM for A/T LIM is:
The FMC is not providing A/T System with N1 limit values. The A/T is using a degraded N1 thrust limit from related EEC.
So as per this above definition on A/T Limit, during normal operation the A/T system uses N1 limit values ( the N1 reference bugs which are placed on the N1 gauge) from the
FMC, and during a degraded operation it uses a degraded N1 thrust from the related EEC
Isn't this a conflict? Because EEC when in ON posn (which is the normal mode) provides the engines rating or places the Reference N1 bugs on the N1 gauage, but the A/T LIM defenition says A/T system takes input from EEC in a degraded mode,
and in normal mode it takes input from FMC
This is where my confusion lies
Thanks a lot