Originally Posted by
pagey
We turn off the apu for de/anti ice. Also close all bleeds and turn off packs.
APU is turned back on after. We start a timer for re-opening bleeds and a slightly longer time before turning the packs back on.
All takeoffs after de-ice are done pressurized.
Why in the world would you takeoff unpressurized? This is for CRJ.
Because the FAA was/is/has/will mandate the upper fuselage be treated with type4 as it is a critical surface per Bombardier. Type 4 fluid shears off and slides right into the strategically placed APU intake destroying the APU compressor blades (screaming loud CRJ APU'S?) and contaminating bleed air.
If your using your using anti-ice, no bleed avail from engines.