Merci beaucoup!
I have another question to ask: why do we use a relatively complicated instrument to measure CAS, as it is an information I don't think pilots need.
On my 172, I only use IAS to assess my safety margin above stall.
For any other purpose (navigation, landing distance) I can imagine, what I need is ground speed, not IAS/CAS.
Wouldn't a simple angle of attack probe do the job?