FMC speed vs IAS window speed
Hi All,
Not sure if this has been covered before (had a quick search to no avail), but was wondering if anyone knew a bit about the autothrottle on the 757/767.
When flying a fixed mach number (e.g. across the pond / at ATC request), there seems to be a general feeling that opening up the IAS window, setting it to Mach, then leaving that to control the speed does a better job than just changing the FMC CRZ SPD.
I wouldn't have thought it makes much of a difference - the A/T is being told to fly at 0.80 (say) by the window, or by the box - same thing.
Any thoughts?
Best wishes, and many thanks,
NW3