Air Systems and Ice Flashcards
Which pressure compression sections can bleed air come from?
Both high and low
When may the engine bleed valves automatically close? (3)
- When APU is starting an engine
- When external air is connected
- Or under low engine bleed air demand such as when air con packs are off
What does HI STAGE mean?
Means excessive air pressure and high pressure bleed valve has closed automatically and locks
What does ENG BLEED VAL (discrete BLEED light on panel) display mean?
Excessive bleed air temp and if excessive the engine bleed valve automatically closes
After starting the first engine what happens to APU bleed valve once engine on speed?
It automatically closes and running engine now provides bleed air to system
What bleed air starts the second engine?
APU, as although the APU bleed valve automatically closes after the first engine started, when the second engine started that closed the running engine’s bleed valve automatically and APU then provided bleed air again
When high thrust settings are encountered what happens to high pressure shut off valves?
They close so only low pressure valves provide the air
APU BBLEED VAL indicates what?
Valve disagree
BLEED ISLN VAL mean?
Valve disagree
What does BLD DUCT LEAK (discrete DUCT LEAK) mean?
System has detected a bleed air leak
5 things air systems used for?
- Engine Start
- Hydraulic Reservoirs
- Pressurisation
- Wing and Engine Anti-Ice
- Air conditioning
What are the two positions of the Air Con Pack valves? (not switch)
Normal and high flow
When pack valve go to high flow?
When pack is required to provide additional air - occurs automatically with no crew action - during ground operation when APU or ground source supplying air, or inflight when one pack is off, or when a recirculation fan is inoperative
When is pack hi flow inhibited? (4)
- One engine supplying bleed air with wing anti-ice on
- Engine inoperative
- Flaps greater than 1
- Aft Cargo fire system armed
Comp temp controllers regulate temperature between what range?
18-30deg c
When in STBY mode what are the three temp positions?
Normal, full cold, full warm
Which temperature does the temp controller demand from the PACKs?
The controller that demands the lowest temp
What does TRIM air system do?
Once compartment controller starts delivering coolest temperature required by individual controllers the trim air system then takes warm bleed air to bring up the temperature in any required zone
Purpose recirculation fans?
Circulate discharged air from flight deck and passenger cabin back into mix manifold to maintain desired level of cabin ventilation while minimising use of bleed air
Foot and shoulder heaters, how work and where? Only work when?
Foot, under floor electric
Shoulders, adds heat to conditioned air flowing from should area
Only work when aircraft is in the air
What does PACK OFF light mean? (2)
Loss of pneumatic pressure or system shut down
PACK TEMP and INOP light mean? (2)
Either a pack controller fault or high pack outlet temperature
If a pack controller fails, what temperature will it remain at?
Last commanded output temperature
What can do if PACK TEMP and INOP light come on?
Use the standby system
If using standby system after PACK TEMP or INOP light and the lights remain on, what should you do?
Wait 5 min and reset the pack by pushing the PACK RESET switch
How confirm a PACK failure?
If after 5 minutes in the standby system the pack reset doesn’t work then confirmed pack failure
What happens if both PACK OFF and PACK TEMP on EICAS?
Pack trip due to internal overheat
TRIM AIR OFF light mean?
TRIM air valve is closed
When trim air off what does system control temp to?
24 deg c
Difference between trim air failure and zone temperature controller failure?
Trim air = TRIM AIR FAIL + each zone will be inop
Zone temp cont fail = just the 3 zones inop
What does a single INOP light mean on a zone? (2) What do?
Fault in zone temp or zone supply duct overheat
Trim air for that zone should be turned off
INOP light on RECIRC Fan mean with switch on? (3)
- fan has failed
- fan has load shed
- fan is inhibited
When are recirc fans inhibited? (2)
- When a cargo fire switch in armed position
- smoke detected in equipment cooling
Equipment cooling provides equipment for what? (3)
- Cockpit instrument panels
- Fwd E/E compartment
- Aft E/E compartment
The overhead panel for equipment cooling only controls what? Why?
Only for forward equipment cooling
No controls for aft equipment cooling or cargo heating - fully automatic when aircraft is powered
Which recirc fan used for fwn equipment cooling?
Left
OVHT light on equipment cooling means?
is supply fan fails
What does pushing ALTN for equipment cooling do? (2)
Turns on alt supply fan and opens overboard exhaust valve
When does the aux supply fan come on for equipment cooling? (2)
- If HMG is only source of AC power
- if both supply fans have failed with ALTN selected
What does SMOKE light mean?
Smoke detected in FWN equipment cooling system
What occurs automatically when SMOKE in equipment cooling light comes on? (3)
And when smoke no longer detected?
- one or both recirc fans turn off
- on or both air con packs switch to high flow
- overboard exhaust valve is latched open
When no longer detected the recirc fans and packs return to normal, overboard exhaust valve remains open
What 4 inputs do the cabin alt controllers get?
- Baro corrected altitude
- Air/ground
- Thrust lever position
- Cabin alt
Do both cabin alt controllers work at once?
Yes
Which cabin alt controller moves the outflow valve?
Just the one selected
If one cabin alt controller fails, what happens?
The other one automatically takes control
Rate limits of auto cabin rate controller?
+500fpm, -300fpm
Dest airport landing altitude selector range?
-1000ft to +14000ft
What happens to cabin pressurisation system when on ground and taking off?
With engines running and throttles advanced beyond 10deg it descends slightly below take off airport elevation
Pressurisation schedule for climb?
Rate proportional to ROC up to 8.6PSI (approx 35K), the a climb schedule above to keep 8.6PSI
When cruise mode established in cabin alt controller?
After 1 min in stable altitude
Once in cruise mode, what cabin alt is maintained?
Compares landing alt with cabin alt and selects the higher of the two (if needing to climb the cabin to a higher landing alt then it climbs at half rate until it is reached)
When does cabin alt enter descent mode?
If a descent of more than 1000ft is initiated
In descend what is cabin actually descended to?
100ft below selected landing alt
What happens on touchdown to press system?
outflow valve is open
CABIN AUTO INOP mean? Position of outflow valve?
Both auto 1 and 1 inop
Outflow valve freezes in last position
How regain control of outflow valve when CABIN AUTO INOP displayed?
Go through to manual
What power does manual cabin alt control use to power the outflow valve?
standby DC bus
When cabin alt warning come on? When cancel?
10000ft
Cancel below 8500ft
When in auto mode does pressure switch automatically close the outflow valve? When normal outflow valve operation restored?
When above 11000ft auto closes, restored once below 9500ft
How positive and negative max diff pressures protected?
Positive and negative pressure relief valves
What anti ice heated by bleed air? (2)
Engine cowls
Three leading edge slates outboard of engines
What antic ice heated electrically? (2)
flight deck windows and all probes
Which windows heated for anti-ice and which for anti–fogging?
Fwd windows both, side windows only anti-fogging
Window INOP light means? (2)
Overheat or inop
If overheat window what can you do?
Reset the system by pushing the switch to off then back to on but waiting in off for 10sec
If a window arcs or is damaged should you turn off the window heat?
Yes
When do probe lights turn on?
After either engine is started
What does TAI mean?
Respective engine anti-ice valve is open
Eng anti-ice valve light mean?
Disagree
Wing anti-ice avail on the ground?
No
Wing anti-ice VALVE light mean?
Disagree
Do not operate wipers when?
On dry windsheilds
Which windows receive supplementary de-fogging air flow?
Front two only
What things occur when TAI switch turned on?
- Engine anti ice valve opens
- If in auto ignition the selected ignitor is on
- TAI is displayed on Upper EICAS
- Max EPR value is reduced
- Min idle setting goes to approach idle
