Air Systems Flashcards
BLEED TRIP OFF light illuminates
- Excessive engine bleed air temperature or pressure
- Related engine bleed air valve closes automatically
- Requires reset
Describe the function of the temperature selectors
AUTO: provides automatic temperature control for the associated zones. Rotating the selector manually sets the temperature
OFF: closes the associated trim air modulating valve
Explain the function of the ISOLATION VALVE switch
CLOSE - closes isolation valve
AUTO:
- CLOSES automatically if:
- both engine bleed air switches are ON AND
- both PACK switches are AUTO or HIGH
- OPENS automatically if:
- either engine BLEED air OR PACK switch is positioned OFF
OPEN - opens isolation valve
Memory aid AUTO function ISOLATION VALVE
Auto functions via the position of the 4 corner switches (bleeds and packs). If any of the four corner switches are OFF, the isolation valve opens, otherwise it is closed.
Explain the function of the TRIP RESET switch
Push (if fault condition is corrected)
- resets BLEED TRIP OFF, PACK and ZONE TEMP lights
- related engine bleed valve OR pack valve OR air mix valve opens
- light remains illuminated until reset
What does the TRIP RESET switch NOT reset?
WING-BODY overheat light
Describe the associated alerting with an E & E bay over temperature on the ground
Alerting is provided through the crew call horn in the nose wheel well
Explain the function of the pressurization mode selector
AUTO - pressurization system controlled automatically
ALTN - pressurization system controlled automatically using ALTN controller
MAN - pressurization system controlled manually by outflow valve switch, both auto controllers bypassed
Altitude that will cause the cabin altitude warning horn to sound
Intermittent warning horn sound when cabin altitude reaches 10,000ft
Explain the function of the cabin ALT HORN CUTOUT switch
Push - cuts out intermittent cabin altitude warning horn
Explain the meaning of an illuminated WING-BODY OVERHEAT light
Left: indicates overheat from
- bleed air duct leak in left engine strut
- left inboard wing leading edge
- left air conditioning bay
- keel beam
- OR APU bleed air duct
Right: indicates overheat from
- bleed air duct leak in right engine strut
- right inboard wing leading edge
- OR right air conditioning bay
Explain the function of the AIR TEMP source selector
SUPPLY DUCT - selects appropriate zone supply duct temperature
PASS CAB - selects forward or aft pax cabin temp
PACK - selects left or right pack temp
Illuminated PACK light
- Pack trip off OR failure of both primary and standby pack controls
- During MASTER CAUTION recall, indicates failure of either primary or standby pack control. Extinguishes when Master Caution is reset
Illuminated ZONE TEMP light
CONT CAB
- duct temperature overheat
- OR failure of the flight deck primary AND standby temperature control
FWD or AFT CAB
- duct temp overheat
During Master Caution light recall
- CONT CAB indicates failure of the flight deck primary OR standby temperature control
- FWD CAB or AFT CAB indicates failure of the associated zone temperature control
- Lights will extinguish when Master Caution is reset
Illuminated OFF SCHED DESCENT light
A/C descended before reaching the planned cruise altitude set in the FLT ALT indicator
What happens if a flight is aborted in climb and returns to the takeoff airport?
The controller programs the cabin to land at the takeoff field elevation without further pilot input.
If the FLT ALT indicator is changed, the automatic abort capability to the original takeoff field elevation is lost.
TRIM AIR switch function
ON - trim air pressure regulating and shutoff valve signaled open
OFF - trim air pressure regulating and shutoff valve signaled closed
Function of the RECIRC FAN
- Reduces air conditioning system pack load and engine bleed air demand
- Air from pax cabin and electrical equipment bay is drawn to the FWD cargo bay where it is filtered and re-circulated to the mix manifold
Function of the EQUIP COOLING SUPPLY switch
NORM - normal cooling supply fan activated
ALT - alternate cooling supply fan activated
Function of the EQUIP COOLING EXHAUST switch
NORM - normal cooling exhaust fan activated
ALT - alternate cooling exhaust fan activated
Explain the meaning of an equipment cooling supply OFF light
Illuminated amber - no airflow from selected cooling supply fan
Explain the meaning of an equipment cooling exhaust OFF light
Illuminated amber - no airflow from selected cooling exhaust
Selecting the alternate fan should restore airflow and extinguish the OFF light within approx. 5 seconds
Meaning of an illuminated DUAL BLEED light
Illuminated amber:
- APU bleed air valve open AND engine no. 1 BLEED air switch ON
- OR APU bleed air valve AND isolation valve open AND no. 2 BLEED air switch ON
How is the air panel configured if the DUAL BLEED light comes on?
- In a way that it would be possible to back pressure the APU
- The light observes the APU bleed valve and the isolation valve and the no. 1 and 2 engine bleed air switches
Explain the meaning of a RAM DOOR FULL OPEN light
Illuminated blue - indicates ram door in full open position
Function of the engine BLEED air switches
OFF - closes the engine bleed air valves
ON - opens the engine bleed air valves when engines are operating
Function of the APU BLEED air switch
OFF - closes APU bleed air valve
ON - opens APU bleed air valve when APU is operating
Function of the PACK switch
OFF - pack signaled off
AUTO - pack signaled to operate in the AUTO mode
HIGH - pack regulates to high flow, provides maximum flow rate on ground with APU BLEED switch ON
