P. Bonsai and IGh
Thank you for your explanations; this was the answer that I was seeking for. So Now, I know the sideslip can be related to difference between AOAs, measured by symmetrical positioned vanes on both sides of fuselage. That makes sense. I believe, for Airbus FBW s, this is the case because there are 3 AOA vanes and 2 of them are symmetrically positioned on sides of fuselage. In airliner, normally this information is not needed to be indicated to pilot, except for the case of engine failure. A twin, with wing mounted engines, is prone to a large side slip angle (so high drag) in the case of engine failure. At critical phases of flight like takeoff phase (which has already lots of drag. I.e. Flaps etc.), the added side slip drag with a deficiency of 50% of thrust may not be acceptable. Now exactly at this moment (namely when needed), Airbus Electronic Slip Skid Indicator turns to show Sideslip angle which is known as Beta Target. This function is named aftersymbol, because (I am sure you are well aware than me) it is used to show side slip angle in Flight Mechanic diagrams.
In fact, after your replies, I found this document for GOODRICH Multi Function -Smart Probes (
http://www.goodrich.com/gr-ext-templ...tot-Static.pdf), which is also explaining how to find local sideslip angle with static pressure differences from the side located ports.
John T.
I fully respect your vast knowledge, but I guess as mentioned above, finding Side Slip Angle by IRS, at least, is not a preferred method. I have also basic but limited knowledge on IRS; IMHO, only the way, if IRS can detect instantaneous sideway acceleration, this may be converted to side slip angle; however the problem is –as you mentioned- IRS works in inertial reference systems and Air mass may also be accelerating and decelerating and cannot be assumed as Inertial reference system. In addition to this, due to cumulated errors (Although somehow eliminated by Kalman filters) may not be precise and accurate enough to drive Beta Target indication on EADI of Airbus FBW.
Intruder
I would like state that I also respect your vast knowledge. From your last reply, if I understand correctly, you are also mentioning theoretically, IRS may be calculating Sideslip from instantaneous lateral acceleration. I am not saying “not possible”, but my idea is as I wrote to J.T.
Away from this subject here are some URLs for OEI flight characteristics.
http://www.cast-safety.org/pdf/5_asymmetric_flight.pdf
http://www.avioconsult.com/downloads...d%20Flight.pdf
Department of Aviation Animation, Click one engine inoperative aerodynamics
Engine inoperative principles in a twin airplane | pilotscafe.com Animation
Again thanks to all replies