Abnormal procedures ‘Eng Shutdown’ Procedure has a little explanation of when you can use the APU bleed after engine shutdown. Without damage there is no restriction, with damage you have to be careful which engine you use it with to prevent contamination from the fire suppressant. If ENG 1 is shutdown with damage you can’t use the bleed at all, if ENG 2 is shutdown then you can shut the bleed crossfeed and use the app bleed to take some load off the good eng.