babyboeing400
25th Aug 2006, 14:39
i can never understand what does it mean when this light comes on..the FCOM vol.2 merely states "A/T computer is calculating a single fixed N1 limit for affected engine(s) when FMC calculations become invalid or if either engine N1 is less than 18%".can anyone please provide me with a more detailed explanation?thanks a millions!
:)
Chopper OZ
7th Sep 2006, 11:12
All it is telling you is that the A/T N1 limit data from the FMC is invalid. I.e. when you select CLB1, CLB2 etc, the data is not being received by the A/T computer. If it is invalid it goes into an alternate mode and sets it's own N1 limit independant of the FMC. The limit light is there alert you to the fact the A/T computer N1 limit is being used instead of the FMC limit. The thrust mode annunciator normally shows dashes as well due to FMC invalid data.