ATR-72 engine failure after V1
For 72/42-500
Engine flame out at V1.... continue with take off (PNF checks Up-trim on live engine and autofeather on dead engine )
+ve rate of climb: Gear up, (up to this point you will be climbing with v2+5)
Acceleration altitude (500ft agl): Set alt....this meant to let speed increase
As speed reaches White bug.....set IAS on ADU, set MCT and flap to zero if normal conditions. If in icing conditions the flap will remain 15.
You note above that you will initially climb at v2+5 before climbing at White bug speed when you reach your acceleration altitude.
You had engine flame out at take off, why would you want climb to 20,000ft. You will basically climb to a safe altitude, hold somewhere for you to get some time to finish the checklist before initiating an approach. In a practical circumstance you will do a circuit if you are visual and land ASAP