MCDU - Thrust Reduction / Engine Out Alt.
I've tried FCOM 4 and all the other usual places, but can't find the answer to this one.
Why are "Thrust Reduction" and "Engine Out" sometimes different by a few feet(typically 30 -100 ft) and at other airfields exactly the same as one another in the MCDU. I understood they normally defaulted to 1500ft above aerodrome level, or is one the aerodrome datum and the other the threshold elevation or something cunning like that. I only ask because it never used to be like that in the MCDU database, I always recall them being identical until the last few months. Can anyone help ?