Originally Posted by
le Pingouin
We ask for "TAS" as that's what TAAATS uses in the flight plan to calculate estimates. If there's a significant difference between what's stored and what the aircraft is flying (e.g. when flying at a significantly different level, after airwork or just because you're not flying what you planned) then we'll get an alert due to the surveillance derived estimate and calculated estimate being too different.
The "surveillance derived estimate".
Would that "estimate" be "derived" from location, groundspeed and track by any chance?