Overview Flashcards
Bleed air is used for:
- Engine starting
- Engine Anti-ice
- Wing Anti-ice
- Air conditioning and Pressurization
- Water tank pressurization
- Hydraulic Reservoir Pressurization
How is pressure controlled?
Pressure regulating shut off valves (PRSOVS)
What are the sources of bleed air?
- Left Engine
- Right Engine
- APU
- HP external air connection
What stage is air taken from?
5th (primary) LP
9th (Secondary) HP
How is the bleed air valve controlled?
Electrically (DC power)
What position is the bleed switch normally in?
ON
What is the temperature when the BLEED AIR TRIP OFF light illuminates?
490 F
What is the pressure when the BLEED AIR TRIP OFF light illuminates?
220 psi
How is the ISOL valve operated?
Electrically (AC)
When is the ISOL valve closed?
ISOL valve switch - AUTO
BOTH engine BLEED air switches - ON
BOTH engine PACK switches - AUTO or HIGH
What causes the ISOL valve to open with the ISOL valve switch in AUTO?
Selecting any one of the PACK or engine BLEED air switches to OFF
Is the ISOL valve affected by the APU BLEED air switch or the ground HP air supply?
No
ISOL valve switch OPEN
ISOL valve remains open regardless of engine BLEED air or PACK switch position
ISOL valve switch CLOSED
Closes ISOL valve
Which side does the APU supply?
Left
Which side does the HP ground air Supply?
Right
How is the APU bleed air valve operated?
Electrically (DC)
APU BLEED air switch ON
Controls the valve electrically and opens the valve when sufficient bleed air is available
APU provides bleed air for how many PACKS on the ground? In flight?
2/1
APU’s primary use
Ground pneumatic source for air conditioning PACK operation and engine starting.
Max APU BLEED air extraction
17,000 feet
How long should the APU run before BLEED air is available?
1 minute
What does system logic look at to illuminate the DUAL BLEED light?
- BLEED air switch position
- APU bleed air valve position
What are the 2 circumstances when the DUAL BLEED light to be illuminated?
1) The APU bleed air valve is open and the number 1 engine BLEED air switch is ON.
2) The APU bleed air valve is open, the number 2 engine BLEED air switch is ON, and the ISOL valve is OPEN.
What is the restriction of thrust with the DUAL BLEED light illuminated after engine start?
Not above idle thrust
The left WING-BODY OVERHEAT annunciator provides detection for:
- left engine strut
- left inboard wing leading edge
- left air conditioning bay
- keel beam
- bleed duct from the APU
The right WING-BODY OVERHEAT annunciator provides detection for:
- right engine strut
- right wing leading edge
- right air conditioning bay
What light cannot be reset using the TRIP RESET switch
WING-BODY OVERHEAT
How does the WING-BODY OVERHEAT light extinguish?
Once the respective pneumatic duct cools
