AMS: Pneumatic, ECS and Pressurization Flashcards
air management system
for a/c to be on, what must be TRUE?
either GPU or one engine running
max diff cabin pressurization vs. outside
9.4 psi
max diff overpressure for cabin vs. outside
9.6 psi
max diff negative pressure (vs. outside)
-0.3 psi
max diff pressurization for T/O and LDG
0.2 psi
What TWO systems comprise the interconnected pneumatic system?
- ECS (Enviro Control Sys)
- WHHAIS (Wing and Horizontal Stabilizer Anti-Ice System)
*circuits are interconnected or segregated by XBV (Cross Bleed Valve)
what is key valve for bleed system?
the PRSOV - the pressure regulating shutoff valves
what happens to the PRSOV during OEI take off?
the PRSOV automatically closes
FAN (fan air valve) does what?
it is regulated by the pneumatic system to maintain desired bleed air temperature
Describe bleed air from engines to use in ECS as if you were a molecule in the air stream:
bypass air coming through FAV pre-cools the bleed air that can go one of two ways:
#1 to anti-ice functions (cooled a bit via FAV)
#2 to heat exchanger where it is cool by ram air or ground a/c (VCS) by ground fan during ground ops
ECS consists of? (6 systems)
- BLEED air inflow (pneumatic system)
- TEMP control system (TCS)
- VAPOR (A/C) cycle air conditioning system (VCS)
- AIR distribution ducting system
- EMERGENCY ventilation system
- FRESH air supply system (on ground)
What is one input for pressurization system crew must put in prior to departure?
LFE
What will DUMP button do? (2 things & a condition)
When pressed, it will:
a) open the outflow valve
b) turn off recirculating fans
** The outflow valve will open until a cabin altitude of 14,500 (?) is reached.
what is a pneumatic limitation above 30,000 feet?
the airplane cannot de-ice and pressurize the cabin at same time
