I would try to use some common sense.
330ft per second is a little over 195kts. Well within the capability of the majority of a/c that have Rad Alt fitted.
It is also however a little under 20,000ft per minute. Which even for a fighter a/c is a pretty astonishing rate of climb/descent.
Civilian Rad Alts start to display at 2500ft (less than 7.5 seconds at 20,000ft per minute descent rate). Rates in excess of the tracking capability produce No Computed Data (NCD) indication.
Now which do you think it is?