Originally Posted by
Volume
Not groundspeed, but indicated airspeed....
In a nutshell: total pressure is constant wherever you have airflow, hence you can place a pitot tube at any location where you have attached airflow, if the probe roughly points into the airflow, it will work satisfactory.
Measuring static pressure only works in places, where the airflow has exactly the same speed as the aircraft. If you would measure static pressure on the upper wing surface, you would actually measure the low pressure which keeps you in the air. Also on the nose fuselage, you have slightly increased airflow speed, an your static pressure is too low. Towards the end of the fuselage your airflow may be more the same as the general airspeed, but the turbulent boundary layer of the fuselage would create some high frequency pressure variations. So it is very, very hard to find a proper place for the static probe.
If you place the static probe in a position where the additional speed due to the airflow around the fuselage is well known, you may correct the measured pressure electronically. This obviously happen here, static pressure measurement is AoA sensitive, so you measure AoA to correct your static pressure.
This way, an AoA failure results in unreliable static pressure, hence UAS and unreliable altitude. Additionally your AoA driven stall warning goes havoc...
Not so nice if you are sitting in row 0.
The link between AoA and indicated airspeed is not so obvious. As part of my profession I get to see a lot of the internals of modern Air Data / Inertial Navigation systems. And without going into detail, the correction from AoA for the static pressure is minimal (other corrections like ground effect, reverse thrust etc are more pronounced and still small). If AoA is way off, it seems more likely a miscompare is triggered between AoA1 and AoA2. This could have all kinds of consequences and warnings which on a 737 probably need to be recognized by a pilot an actively worked (i.e., manually switch Air Data source of affected side to standby or opposite).
Agree with the stall warning, the amber band etc will be all over the place.
edit:
link to Boeing Aero magazine regarding AoA indication on Boeing aircraft.