Pneumatics Flashcards
- What are the three sources of air on the ground?
External, APU and engine air.
- What’s another name for 4th and 7th stage air?
Mid and high stage.
- What’s the purpose of pressure regulating shutoff valve?
Maintain a maximum bleed manifold pressure of approximately 40 psi.
- What’s the preferred source of air and why?
4th stage because it has lower pressure and temperature.
- What’s the purpose of 7th stage bleed valve?
To supply supplemental air to maintain minimum bleed manifold pressure 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’s the purpose of the isolation valve?
Isolate left and right bleed air manifolds.
- Other than using ISOLATION valve switch, how else can isolation valve be opened?
Selection of APU BLEED AIR switch with weight on wheels, or selection of ENGINE START or Crank switches.
- If the isolation valve cannot be opened electrically, how else can it be opened?
It incorporates manual wrenching device.
- What computers control operation of the bleed air system?
Bleed Air Controllers (BACs)
- What are BACs responsible for?
Regulation of bleed air manifold temperature and supply pressure. (i.e., responsible for min pressures and all temperatures)
- What happens to high stage bleed pressure when a PACK switch is selected to OFF?
It resets 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 the precooler outlet during wing anti-ice operation with single ENG BLEED switch selected to ON?
500°F
