Air Systems *** Flashcards
Flight Deck Fan Switch controls what?
Recirc fan for flight deck.
Is flight deck fan avail in flight?
NO
How does flight deck fan operate on ground?
- With all PACKS OFF, cabin air supplied
- With one PACK ON, fan increases flow of air (like ac in a car)
Flight Deck temp range in AUTO?
18C-29C
ECS Zone Reset Switch (ZONE RST)?
- Resets zone temp controller if fault has cleared
- If OVERHEAT cleared, reopens master trim air valve and FWD or AFT LLCTRSOV.
What will trigger ECS Zone SYS FAULT Light (Amber)?
- Temp zone duct overheat
- Zone Temp controller fault
- Trim Air Switch OFF
- Master trim air valve failed CLOSED
What will reset Lower Lobe Cargo conditioned air supply duct SOV’s if they were closed by duct overheat?
Turning the LLCCAFR switch OFF momentarily.
LLCCAFR FWD LOW selector?
2/3 of Pack #3 conditioned air distributed to FWD LLCC. Pack #3 remains in HI FLOW during cruise.
LLCCAFR AFT LOW selector?
2/3 of Pack #2 conditioned air distributed to AFT LLCC. Pack #2 will remains in HI FLOW during cruise.
LLCCAFR BOTH LOW selector?
2/3 of Pack #3 and #2 conditioned air distributed respectively to FWD and AFT LLCC. All Packs will remain in HI FLOW during cruise.
LLCCAFR FWD HIGH selector?
All Pack #3 conditioned air distributed to FWD LLCC. All packs op in HI FLOW.
LLCCAFR AFT HIGH selector?
All Pack #2 conditioned air distributed to AFT LLCC. All packs op in HI FLOW.
AFT CARGO HT Switch OFF?
Shuts OFF aft cargo heat bleed air to compartment.
AFT CARGO HT Switch ON?
- Opens Overheat SOV to provide bleed air to compart
- Temp Control Valve OPENS/CLOSES to regulate temp
- Overheat SOV will automatically re-CLOSE for overheat protection
How many zones are air conditioned?
7
3 - FD/UD/CR
2 - MD Fwd and Aft
2 - LL Fwd and Aft
The 4/10 Toggle Switch is for use in what compartment only?
LL AFT
What are the LL Zone(s) Temp Range?
4C-29C
Main Deck Temp Range?
4C-29C
Why is AFT CARGO HEAT normally selected ON when LLCCAFR is in AFT LOW/HI?
Ensures compartment floor temp is maintained above freezing.
TRIM AIR Switch ON?
- Master Trim Air Valve OPEN
- Flight, Upper, Main Deck Trim Air Valves Op Auto
- Auto & Manual Selection of Pack Controllers Enabled
TRIM AIR Switch OFF?
- Master Trim Air Valve CLOSED
- Pack Temp Regulated to avg temp as selected by Flight Deck Temp selector in AUTO
- Cabin Temp Panel control of upper deck inhibited
- PTC A selected
- PTC B (auto and manual) inhibited
AFT CARGO HT air source?
Center section of bleed air duct. (Bleed air manifold)
What does MANUAL selector position of the temp controllers do?
Sets trim air valves manually.
On power up, what is the target temp for flight deck and crew rest areas?
24C
Trim air in not available to the flight deck, upper deck, main deck system if?
- Trim Air Switch OFF
- Center Section of bleed duct isolated.
How many Pack Temp Controllers (PTCs) are there?
Two - A and B
How many channels does each PTC have?
Each PTC has three channels. One for each pack.
What happens when a PTC detects a fault in pack channel?
Control is switched to other PTC.
How is pack operation for a failed PTC restored?
Push the Pack Reset Switch
What happens if a fault or overheat of a PTC is detected?
Respective pack valve closes resulting is pack shutdown.
Center duct air provided for?
- PACK 2
- TRIM AIR
- AFT CARGO HEAT
- Cargo Smoke Detectors
- Potable Water Vacuum Air
- LL cargo TRIM AIR
Generally speaking, how is the air temp regulated in each of the 7 zones?
A modulation valve in each individual air duct allows varying amounts of trim air to mix with the conditioned air.
Do all 3 PACKS try to regulate their respective air to different temperatures?
NO. They have a common discharged temperature based on the zone demanding the lowest supply temp.
How can we reset the LL air temp system (3)?
- LLCCAFR OFF then back ON
- ZONE RESET Switch
- Turn Temp Selector to MANUAL then back to AUTO
Under what conditions would trim air be unavailable to the flight deck, upper deck, crew rest, and main deck?
- EICAS advisory TEMP ZONE is displayed.
- Center section of the bleed duct is isolated.
- EICAS Advisory message TRIM AIR OFF is displayed.
- The Master Trim Air switch is OFF
If TRIM AIR in not available to the flight deck, upper deck, or main deck (for the 4 reasons below ) how is temperature controlled in the cabin?
EICAS TEMP ZONE
Center section isolated
EICAS TRIM AIR OFF
Master Trim air switch is off
Backup Mode
- If Flight Deck Temp selector avail to PTC, packs regulated to achieve temp set by selector 18 C to 29C
- If Flight Deck Temp selector not avail to PTC, packs regulate to achieve last temp set
- If last temp set unavailable to PTC, packs regulated to achieve avg flight deck temp of 24C
L/R duct air provided for?
- WAI
- LE Flaps
- HYD Reservoir and Pressure (L 1&2, R 3&4)
- HYD Demand Pump
- PACK 1 (L duct) & PACK 3 (R duct )
If a duct section is isolated and L/R valve closed, how will LE flaps extend?
Isolated side will extend electrically while opposite side extends normally with available pneumatic air.
NOTE There will be asymmetry until both are fully extended.
Is trim air for the LLCs supplied by controlling the Master Trim Air Valve?
NO
- Trim air for the LLCs is provided directly from the bleed air duct. (Bleed air manifold )
Pack HI FLOW button logic?
ON - All PACKS in HI FLOW
OFF - PACK HI FLOW dependent on LLCCAFR
PACK RST Switch used for?
- Resets PACK fault protection system
- Restarts PACK after auto-
SYS FAULT in amber when overheat or other system fault
What happens if we turn a specific PACK selector to OFF?
- CLOSE the PACK Valve
- Extinguish SYS FAULT Light for the PACK RST Button
- Resets Pack Fault Protection
When the LLCCARF Switch is OFF, what controls PACK outlet temperature?
The flight deck, upper deck, or main deck temperature zone requiring the coolest temperature.
When the LLCCARF Switch is in FWD HI, what happens to PACK outlet temperature?
- PACK 3 maintains FWD LLC at temp set by selector
- Flight deck, upper deck, or main deck temperature zone requiring coolest temperate controls PACK outlet temperature of PACKS 1 and 2.
When the LLCCARF Switch is in AFT HI, what happens to PACK outlet temperature?
- PACK 2 maintains AFT LLC at temp set by selector
- zone ( FD/UD/CR/MD TEMP ) requiring coolest temperate controls PACK outlet temperature of PACKS 1 and 3.
When the LLCCARF Switch is in LOW, what happens to PACK outlet temperature?
- Outlet temp of PACK supplying respective LLC won’t be higher than outlet temperature of other 2 PACKS.
- The respective LLC temperature is regulated by closing the TRIM AIR MODULATING VALVE and supplying cooler air from the pack supplying air to the compartment or modulating the CARGO TRIM AIR VALVE to supply warmer air.
Trim Air is not available for the FWD LLC if?
- Center duct isolated
- FWD LLC zone duct overheat occurred
- FWD LLC Cargo Trim Air Valve CLOSED
If Trim Air is not available for the FWD LLC, what occurs?
BACKUP MODE:
- If FWD LLC Temp selector setting is avail to PTC, PACK 3 is regulated to achieve the set temp.
- If FWD LLC Temp selector setting is not avail to PTC, PACK 3 outlet temp is regulated to achieve the temp sensed when backup mode was initiated.
- If FWD LLC temperature is unavailable to the PTC, PACK 3 outlet temp is controlled to the outlet temperature sensed when backup mode was initiated.
If Trim Air is not available for the AFT LLC, what occurs?
IT’S IDENTICAL TO FWD LLC TRIM AIR LOSS BUT USES PACK 2 INSTEAD OF 3!