Air Systems - Environmental & Pneumatics Flashcards
PACKs go to high flow for three reasons-
When is it inhibited?
Single PACK ops
Recirc Fans off
APU is only source of air
**High flow is inhibited for Single Engine ops
How much fuel does being in low flow save?
Approximately 25 pounds/hr
How do you know which switched are electrically actuated and with are hydraulically actuated?
Anything labeled “off” is electric/electric
Anything labeled “valve” is electric/pneumatic
What two things will command the APU valve closed?
- Left Engine Bleed Valve open
- Isolation Valve open with Right bleed on
If you turn the Recir fans off inflight to force PACKs into high flow what caution should you observe with the 757?
Do not turn of the Left fan because it will cause the overboard exhaust fan to latch open, PACK will compensate by going to high flow. Problem is when you turn fan back on, PACK goes to low flow, rev stays open and you may not be able to maintain pressurization
Button on PACK light-
If both ‘INOP” and “PACK OFF” lights are on read the first letter and think-
- Internal PACK Overheat
- puts you in standby mode and you willed to use the dial that is below the button
What happens if you have a zone control failure that you can’t reset?
That zone goes to a “comfortable” temperature
The temp select “INOP” light can mean four things-SOFT
Switch
Overheat
Fault
Trim Air
What does the gasper fan on the 764 do?
Just pushes more air out of the vents
Do the needles on the Pneumatic panel need to be matched?
No-can be up to 30psi apart as long as they are both over 25psi
The INOP/PACK OFF light in the middle of the panel
What would INOP represent?
What would PACK represent?
- A problem on the “out” side of of the PACK
- A problem on the “input” side of the PACK
**Just look at the button, top vs bottom
The INOP/PACK OFF light in the middle of the panel-
If both lights were on what would it mean?
The PACK itself is the problem
If the Auto controller fails what will the valve do?
What action could pilot take?
- Stay in the current position
- Move switch to the “N” position to get a preset position
“INOP” light near top of panel comes on for what reasons? (SOFT)
Switch position
Overheat
Fault in system logic
Trim Air
757 Equipment Cooling
Overboard exhaust logic is designed to protect the Mix manifold because
Air from the equipment cooling flows back to the mix manifold so if there was smoke in the E+E it would end up flowing to the cabin