Originally Posted by
john_tullamarine
Providing you have zero sideslip, no. The purpose of the quite lengthy certification flight test work done to establish the AFM PEC data is to cover all this sort of stuff.
Are you sure about this?
You can't be perfect, there is always some sort of turbulence around the static pressure source, the dual static source is useful to counted sideslip but does it counter it perfectly ?
I don't know the specific term in english but during flight test they use some sort of pole/rod to measure air data very far away from the aircraft.
Originally Posted by
john_tullamarine
Only because I'm totally confused, whence comes 30.5 ?
The pressure vs altitude follows approximately an exponential law, so if the pressure is 10% lower, the pressure rate with altitude is 10% lower as well.
30.5ft/hPa is the figure at 500ft, IF you assume the figure at sea level was 30ft. It was just to give an idea of the difference it made at 500ft : not much.
Originally Posted by
Clinton McKenzie
What is the margin of error of a 'blind' Mode C encoder output?
What is the maximum allowable 'delta' between an aircraft's Mode C encoder output and the reading on the aircraft's altimeters (when set to 1013 hPa)?
That's a very technical question.
I'll try to make a parallel with what I know.
In the black boxes, all values are rounded down to one resolution.
For example, if the altitude is coded with a resolution of 4ft, an altitude of 3ft will read 0.
This problem is most visible on the latitude/longitude parameters, since the resolution can be some meters..
Are you referring to the same kind of problem ?