oceancrosser,
Thanks for the reply,
I agree that we are totally free to use speedbrake.
I just wonder why the FMS’s algorithm draw such unachievable path without extra drag (speedbrake) path in spite of the below assumptions in the FCOM.
“The path to the first constraint is based on:
• idle thrust
• speedbrakes retracted
• FMC cruise wind
• wind entries on the DESCENT FORECAST page
• predicted use of anti-ice
• applicable target speed”
Besides, in my previous types, i.e. B737CL, B737NG and A320, I could follow VNAV PATH down to FAF in most situations when no short cut or no detour from STAR.
However in case of B767 it seems I have to elect not to use VNAV descent or to use VNAV with help of speedbrakes in the deceleration portion.