Hi SAS108,I think you meant to type:Pitch angle = Flight path vector + AOAApparently the AOA in this equation is the one thats displayed on the AOA indicator on the PFD, although its not exactly the same as 'aerodynamic' AOA which is measured relative to the mean chord line of the wing.The AOA displayed in the cockpit is measured relative to the body line of the fuselage, the same line to which pitch angle is measured, which is convenient because it allows use of the simple equation above. Also, its a lot easier to measure the AOA when its defined in this way (ie. relative to the body line of the fuselage) than it would be if you tried to take account of the mean chord line, which changes its position depending on flap/slat position. Ian's photo of the AOA vane is good because it makes it clear how this is being measured - I didn't know how it was done before this.Anyway, these are my conclusions.

Hi Craig,You're right, + and - is the most difficult part of mathematics :-)Of course it should read Theta = gamma + alpha.This equation is quite central in performance calculations because the flight path vectors incidence to the horizon, measured in radians, is the same as the acceleration available. Furthermore, gamma * TAS gives you the Rate of climb or descent (if gamma < 0). Just watch the unit of that ROC/D because calculated by the expression above you will get it in Nm/hour, so you have to convert to feet per minute. One knot is equal to 101.27 feet per minute.I believe that we can say that the subject is exhausted :-)/SAS108