Flyman35
You are reading from AIR DUAL BLEED FAULT. If ENGINE1 BLEED FAILURE is because of leak, fire or start valve failed open the APU bleed is to the left of crossbleed so cannot be used. Hence no pressurisation so descent to FL100. If you go down and read ENGINE2 BLEED FAILURE for the same reason it asks you check crossbleed is closed and tells you to start the APU and below FL225 use APU bleed which is to the left side of the closed crossbleed, so can be used. It allows you to maintain FL225 which is the maximum altitude on APU bleed. If the dual bleed loss was do to other reasons then also you can use APU bleed and keep FL225.
Last edited by vilas; 1st Nov 2013 at 14:17.