AOA sensors
Ok, this might be a really daft question but its gone from being a simple "by the way what does this mean" query to a sad obsession!
On the 757 DFDAU, one of parameters is AOA1 and AOA2, I'm assuming these give readings of the AOA sensers on either side of the aircrafts nose.
In straight and level cruise, with a normal 2.5 (ish) degree upward nose attitude on the EADI the readings on the DFDAU are around -7.21 or -7.38 degrees.
Reading the maintenance manual, the sensors pivot at the front and a +ve reading indicates the vanes are pointing down (ie there is a downward AOA), but in the cruise the indications show they point up and therefore give an upward angle of attack.
However, as we slow down the reading increases (ie it goes from -7. something to -6. something), meaning the AOA is decreasing.
To maintain a level attitude with decreasing speed the AOA must increase - surely. Why do the sensors indicate a decreasing AOA with decrease in speed?
Can someone answer what may be a really obvious question?!