Systems 5 Pneumatics

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Systems 5 Pneumatics
2013-08-01 19:05:43

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  1. Compressed air for the pneumatic system can be supplied from what sources?
    • Engines Bleed Air
    • APU
    • Ground air source.
  2. What are 5 common systems the utilize compressed air from the pneumatic system
    • Air Con/ Cabin pressurisation
    • wing and Engine De-Icing
    • Engine cross-bleed starting
    • Hydraulic reservoir pressure
    • Air-Driven Hydraulic pumps
  3. What compressor stages is bleed air normally taken from?
    Intermediate to low pressure
  4. When is air bled from the high pressure stages of the compressor, and how is it activated
    During high demand times

    Automatically by a pneumatically operated High Pressure Reg valve (HPV) at the HP stage outlet.
  5. What is the typically maximum across skin loading aircraft are stressed to?

    What can it exceed this by during max climb rate?
    9psi max

    can exceed by 0.25psi

    8000ft cabin pressure at 40,000ft give 8.3 psi
  6. How is cabin pressure controlled
    Via a pressure controller which passes a signal to an outflow valve.

    Control of outflow not inflow is the key.

    Rate of change can be set in the cabin for climb and descent
  7. What is the max Negative differential pressure across the hull?
  8. What is the max permissibly rate of change of cabin pressure in ft/min and psi/min?
    1500 ft/min

    0.16 psi/min
  9. How much fresh air must be supplied per pax
    1 lb per person per minute

    not less than 0.5 if the system breaks.
  10. Carbon monoxide content must not exceed what?
    1 part in 20k