^^^yup this is what I was taught.
MCDU: uses winds entered or uploaded into the box (CLIMB/CRUISE/DESCENT) to compute GS and ETAs. I.e. previously measured or forecasted winds.
ND: uses actual/current winds (as shown on ND, furnished from ADIRS) to compute GS and ETA.
Hence ND is more accurate, uses actual conditions, MCDU uses planned/forecasted conditions
Last edited by Airmann; 13th September 2012 at 10:34.