Bleed Air/AC/Press. Flashcards
The APU provides bleed air to the ____ (L/R) duct
Left side of the system
A high pressure external air connection provides bleed air to the ____ (L/R) side of the system
Right
Bleed air is used for: (6 options)
Engine starting
Engine anti ice
Wing anti ice
Air conditioning and pressurization
Water tank pressurization
Hydraulic reservoir pressurization
The ___ Stage, or ____ pressure stage, is the primary source of bleed air from the engine
5th stage or low pressure stage
When the ___ (#) stage air is insufficient for bleed system requirements, the ____ (high/low) stage valve in the ___ (#) stage, modulates open to maintain adequate pressure
5th
High
9th
T/F
When the engine is not running the bleed valve automatically closes.
True
The normal position of the engine bleed air switch is in the ____ position
ON
What does an illuminated BLEED TRIP OFF light mean?
The pressure regulating shutoff valve (PRSOV) has exceeded a predetermined limit for pressure/temperature and the engine bleed valve has closed automatically.
The TRIP RESET button on the bleed air panel does what?
Resets the pressure regulating shutoff valve (PRSOV) when the over pressure or over temperature condition has dissipated
With the ISOLATION VALVE in AUTO, what causes the valve to close?
Both engine bleed air switches on
Both pack switches in AUTO or HIGH
With the ISOLATION VALVE in AUTO, what causes the valve to open?
Placing any one of the pack or engine bleed air switches to OFF
The isolation valve position is not affected by the ______ or _____
APU BLEED switch
Ground high pressure air supply
The isolation valve is ____ (AC/DC) operated
AC
The APU can provide bleed air for ___ packs on the ground? In flight?
Two packs on the ground
One pack in flight
APU bleed air is available up to an altitude of ____
17,000 ft
After the APU has been started, when can bleed air be supplied?
One minute after APU GEN OFF BUS light has illuminated
What does the DUAL BLEED light indicate?
What causes it to illuminate?
It illuminates to remind you that a back pressure of air to the APU is possible
It illuminates based off switch position and is independent of engine operation. Caused by two conditions:
- APU bleed air valve is open and the engine 1 bleed air switch is ON
- APU bleed air valve is open, the engine 2 bleed air switch is ON, and the isolation valve is open
With the DUAL BLEED light illuminated after engine start, the crew should not ___
Operate the engines above idle thrust
The WING-BODY OVERHEAT light indicates what?
A hot bleed air leak has been detected in the respective system
T/F the WING-BODY OVERHEAT light can be extinguished using the TRIP RESET button
False. The system must cool for the light to extinguish
Which pack supplies air to the flight deck?
Left pack
T/F: Both packs can be supplied by one engine
False
A single pack is capable of maintaining pressurization up to what altitude?
Maximum certified ceiling
41,000 ft
The pack valves are ____ controlled and _____ Operated
Electrically
Pneumatically
What two conditions cause the packs to switch to high flow when the switches are in AUTO?
When is the automatic switching to high flow inhibited? 2 answers
- If only one pack is operating
- When both engine bleed switches are off and the APU bleed switch is on
- When on the ground
- In flight with the flaps extended
When should the packs NEVER be selected to HIGH?
With the engine bleeds ON, during takeoff/approach/landing
What does the PACK TRIP OFF light mean?
What happens when it illuminates?
How do you extinguish it?
The pack temperature has exceeded its limits.
The corresponding pack valve automatically closes and the mix valve drives to the full cold position
Push the TRIP RESET once the situation has been corrected
What does the RAM DOOR FULL OPEN light mean?
When is it activated?
The ram air inlet doors are fully opened. This occurs automatically on the ground, or in flight with flaps extended.
With the recirculation fan in AUTO, when is the fan turned off in flight?
If either or both packs are selected to HIGH
The SUPPLY DUCT AIR TEMP switch displays what temperature?
The air temperature in the supply duct overhead the passenger cabin
The DUCT OVERHEAT light means what?
What does this cause the system to do?
How do you reset this light?
There is an overhead condition in the hot air distribution duct.
The air mix valves drive to the full cold position.
The TRIP RESET button, once the overheat is no longer present
The EQUIP COOLING “OFF” light means what?
Either the respective normal equipment cooling supply or exhaust fans are producing sufficient airflow. Selecting the ALTERNATE starts the other fan and should extinguish the OFF light within 5 seconds
How can the Overboard exhaust valve be opened through switch configuration?
During smoke/fumes removal the valve opens when either pack is set to HIGH and the RECIRC fan is set to OFF
What happens if the in use cabin pressure controller detects a fault?
The AUTO FAIL light illuminates
Pressure control automatically transfers to the other auto controller
ALTN light illuminates
What happens if both cabin pressure controllers fail?
The AUTO FAIL light will illuminate and the ALTN light will extinguish
What conditions can cause the AUTO FAIL light to illuminate?
Controller fault
Excessive differential pressure
Excessive rate of cabin pressure change
Loss of DC power
High cabin altitude
Outflow valve control fault
If the cabin altitude exceeds _____ ft the cabin altitude warning horn sounds.
How can the horn be silenced?
10,000 ft
The cabin ALT HORN CUTOUT button, or by descending below 10,000 ft
When manually controlling the pressurization outflow valve, what must be done before entering the landing pattern?
Slowly position the outflow valve to full open to depressurize the aircraft. Verify the differential pressure is zero
The aircraft has ____ positive pressure relieve valves that do what?
Two
The valves prevent overpressure damage to the airplane structure
The positive pressure relief valves ____ (do/don’t) require intervention from the crew to activate
Don’t
The positive pressure relief valves open at ____ psi differential, limiting the differential pressure to a maximum of ____ psi
8.95
9.1
The OFF SCHED DESCENT light means what?
The airplane is descending before reaching the planned cruise altitude. The controller will program the aircraft to land at the takeoff field elevation without pilot input.
What causes the automatic capability for the pressurization system to plan a return to the departure elevation?
If the FLT ALT is changed
T/F: Normal operating differential pressure is allowed within the amber band
True
The pressurization cruise mode starts when the aircraft reaches ____ psi within the selected altitude
0.25
The pressurization descent mode starts when the aircraft descends ____ psi below the selected FLT ALT
0.25
