Pneumatics Flashcards
On the ESC/PRESSURIZATION synoptic page, what do the BLUE and White numbers displayed on the zones of the aircraft?
BLUE - Requested Temp
White - Is Zone Temp
What are the air conditioning temperature select ranges in AUTO and MANUAL?
Auto: 60° to 90°
Manual: 35° (Cool Air Manifold Min Temp) - 230°
What are the three sources of air on ground?
External, APU and engine air
What’s another name for 5th and 8th stage air?
Mid and High stage
What’s the purpose of pressure regulating shutoff valve?
Maintain a maximum bleed manifold pressure of approximately 40.5 psi
What’s the preferred source of air and why?
5th stage because it has lower pressure and temperature
What’s the purpose of 8th stage bleed valve?
To supply supplemental air to maintain bleed manifold pressure of 14 to 35 psi depending on configuration and existing conditions
What’s the caution associated with use of external air?
Do not connect air with electrical power off
What are the requirements for APU load control valve to open in-flight?
Both engine bleed air switches, both pack switches, and both wing anti-ice switches must be in OFF position.
What’s the purpose of isolation valve?
In the normally closed position, it isolates left and right bleed air manifolds
Other than using ISOLATION valve switch, how else can isolation valve be opened?
APU air switch with weight on wheels, or engine MASTER START or CRANK.
Other than using ISOLATION valve switch, how else can isolation valve be opened?
It incorporates a manual wrenching device
Why does one pack shut down after selection of MASTER START or CRANK, and another shut down with selection of L or R ENG START?
This shutdown is designed to prevent large pressure bump during start by initiating two smaller ones that shouldn’t be as noticeable
What’s the caution associated with use of engine bleed air and APU air?
They shouldn’t be selected ON at same time
What computers control operation of the bleed air system?
Bleed Air Controllers (BAC’s)
What are BAC’s responsible for?
Regulation of bleed air manifold temperature and supply pressure (i.e., responsible for min pressures and all temperatures)
What wing temperature is maintained during wing anti-ice operation?
Approximately 130°F
What happens to high stage bleed pressure when a PACK switch is selected to OFF?
It’s reset to 35 psi
What temperature would you expect at precooler inlet during wing anti-ice operation?
Maximum of 630°F depending on power lever position
What precooler outlet temperature would you expect under normal operating conditions?
400°F
What’s the maximum temperature of bleed air at precooler outlet during wing anti-ice operation with single WING ANTI ICE switch or single ENG BLEED switch selected to ON?
500°F
