Originally Posted by
Vessbot
But I did look at what my manual says, and (not explicitly, but suggestive language) that what is displayed on the PFD is CAS.
I don't know that all aircraft use the same terminology but what Honeywell and Douglas displayed on the MD-11, MD-90, and 717 PFD was Computed airspeed. I could provide a bit more detail on the derivation if needed. I would argue that the indicated airspeed was CAS (Computed Air Speed not Calibrated Air Speed). TAS is a separate numeric readout that is clearly identified as TAS on the flight decks I worked on.