Pneumatics Flashcards
What PSI bleed air is supplied for the surface de-ice system?
18 PSI
Can only one engine supply enough bleed air for the pneumatic and vacuum systems?
Yes
Where is the bleed air ducted to when it leaves the engine?
The respective L or R flow control unit
What type of line tees off the engine bleed-air line forward of the firewall and flow control unit?
A pressure supply line
What does the pressure supply line contain pneumatic pressure for?
To operate surface de-ice system, rudder boost, door seal, and flight hour meter
What is used to change the pressure to a vacuum to operate the gyro instruments?
An ejector
What unit is used to regulate the mixture of engine bleed air for pressurization along with the ambient air?
The flow control unit
What are things the pressurization air is used for?
Heating, cooling, pressurizing
What’s the suction gage indicate?
The gyro suction (vacuum system)
What does the pneumatic pressure gage indicate?
Air pressure available to the de-ice distribution valve, vacuum system, bleed air warning, rudder boost, hour meter, and door seal.
What’s the purpose of the bleed air warning system?
Used to alert the pilot when a pressurization line or pneumatic line ruptures
At what temperature will the bleed air warning system alert?
204 degrees F
How does the bleed air warning system alert?
Warning lights labeled L BL AIR FAIL or R BL AIR FAIL
What could a severe bleed air leak do to engine power and ITT?
Decreased torque, increased ITT
If the bleed air valve is in the INST AND ENVIR OFF position, what should you look for?
Increase in torque and decrease in ITT
*would indicate a severe leak was isolated
What should be done anytime a warning light illuminates?
Respective bleed air valve switch positioned to INST AND ENVIR OFF
What switches controls the pressurization of the cabin?
BLEED AIR VALVES
What are the 3 positions?
OPEN, ENVIR OFF, and INST & ENVIR OFF
What happens when the bleed air valve switches are in OPEN?
Environmental flow control unit and pneumatic instrument air valve open
What happens when the bleed air valve switch is in the ENVIR OFF position?
Environmental flow control unit closes and pneumatic instrument air valve remains open
What happens when the bleed air valve switches are in the INST & ENVIR OFF position?
Environmental and pneumatic flow valves are closed
When does the door seal inflate?
After liftoff
What landing gear safety switch controls the door seal 4PSI valve?
The left
What is required to make the flight hour meter work?
Bleed air and DC power
What landing gear squat switch controls the hour meter?
The right
What’s the limitations of the bleed air system for the: Pneumatic Gage? Vacuum gage?
Pneumatic: 12-20PSI
Vacuum:
15-30k ft MSL — 3.0-4.3in Hg
SL - 15k ft MSL — 4.3-5.9in Hg
What’s 2 malfunctions could lead to a lack of sufficient heat in cruise that cannot be remedied by switch from AUTO to MAN HEAT?
A dead flow pack or because a bypass valve motor has failed
