I have a question regarding the SRS mode and acceleration altitude.
What reference of barometer causes the SRS mode to switch to CLB mode if STD was set below the acceleration altitude?
1/For example, if i were to input an acceleration altitude of 4000ft into the PERF TAKEOFF page, and climbing out i set STD on the barometer. Will the aircraft accelerate on the PFD Altitude at 4000ft with the STD reference or 4000ft on a QNH reference???
2/ So if i decide to takeoff with 6000ft in the FCU, trans alt 6000ft, but the departure has an early constraint at 4000ft and i suddenly set STD straight away after takeoff, will ALT CST level the aircraft at 4000ft +/- the STD deviation from QNH. Say its 1003 mb at lgw (200ft amsl), i pull STD which is 300ft difference, i reach the constraint of 4000ft with STD accidently set, will the PFD altitude display 4300ft????