Mark Hansen wrote:


Although Part 97 and the AIM are silent on whether Approach Categories
are IAS, TAS, or ground speed, how could they possibly be anything other
than IAS?


I'm not sure sure Part 97 is silent on the issue. It says that the categories
are based on the "speed of VREF, if specified, or if VREF is not specified,
1.3 Vso at the maximum certificated landing weight".

VREF and Vso are IAS references, aren't they?

So it would seem. ;-)