This standard provides minimum performance criteria for air data instruments intended to provide cockpit indication of: aIndicated airspeed (Vi) bComputer airspeed (Vc) cTrue airspeed (Vt) dEquivalent airspeed (Ve) eMach number (M) fAltitude (H) gVertical speed (Hpr) hMaximum operating limit speed (Vmo) iTrue angle of attack (αt) jFree air temperature (Tfat) kTotal temperature (Tt) These functions shall be derived from a central air data computer (AS 417) and through system wiring applied to the respective indicator.