A320,
"It depends on what you are measuring as to which instrument to use. The Radalt isn't even required for IFR flight but a pressure altimeter is. Why does the FAA require the use of a Sensitive Pressure Altimeter over a Radalt for IFR flight? When you understand this question, you will understand the answers you have been given here from pilots."
Well it is obvious - if you only have one instrument it has to be the altimeter as radalt does not work above 2500 feet above ground level.
"Why do you prefer radalt over pressure altitude when the NTSB lists radalt as ":not working or unconfirmed","
The radalt appears to be working as ground proximity warning was working. Only radalt provides that.
"the radalt is traveling way outside it's tracking capability of 330 fps,"
The vertical speed was much less than 330 fps.
" and the objects it is measuring from is unknown?"
You can see what is was measuring from by counting back from the impact point where the longitudinal acceleration went strongly negative. There are no buildings there to confuse it. I think you are confused. How do you account for the strong longitudinal acceleration if the plane did not hit?
"Furthermore, the NTSB lists Pressure Altitude as "working and confirmed" and is operating well within it's calibration rated to M0.86."
We have covered this. At high altitude the pressure altimeter would no doubt be calibrated to M 0.86 but at low altitude the plane is not allowed to fly that fast so why would it be calibrated to M 0.86? In fact, how could they do the low altitude tests to determine the calibration errors at speeds beyond which the plane is permitted to fly?
I notice that you are very adept at finding statements on the Pilots for 9/11 Truth website. I suspect you are a member. I suspect you personally think the plane flew over the Pentagon. Do you think the last radalt recording was from the roof of the Pentagon?
