Chapter 2: Air Systems Flashcards
Explain the meaning of an illuminated BLEED TRIP OFF light.
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 control toward C (cool) or W (warm) manually sets the desired temperature.
OFF – closes the associated trim air modulating valve.
Explain the function of the ISOLATION VALVE Switch.
CLOSE – closes isolation valve.
AUTO –
- isolation valve closes automatically if both engine BLEED air switches are ON and both air conditioning PACK switches are AUTO or HIGH.
- isolation valve opens automatically if either engine BLEED air or air conditioning PACK switch positioned OFF.
OPEN – opens isolation valve.
Note: Auto functions via the position of the four 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 opens, or related pack valve opens, or related air mix valve opens.
- light remains illuminated until reset.
The TRIP RESET switch does NOT reset a WING-BODY OVERHEAT light.
Describe the associated alerting with an E & E bay over temperature on the ground.
If an over temperature occurs 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.
Recall the cabin altitude that will cause the cabin altitude warning horn to sound.
Intermittent Cabin Altitude Warning Horn sounds when cabin reaches 10,000 feet altitude.
Explain the function of the cabin ALT HORN CUTOUT Switch.
Push- cuts out intermittent cabin altitude warning horn.
Cabin altitude warning horn sounds when cabin altitude is greater than 10,000 feet.
Explain the meaning of an illuminated WING-BODY OVERHEAT light.
- left light 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 light 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 Temperature (AIR TEMP) Source Selector.
SUPPLY DUCT – selects appropriate zone supply duct temperature.
PASS CAB – selects forward or aft passenger cabin temperature.
PACK – selects left or right pack temperatures.
Explain the meaning of an illuminated PACK light.
- Indicates 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.
Explain the meaning of an illuminated ZONE TEMP light in the following areas.
- CONT CAB (control cabin) indicates a duct temperature overheat or failure of the flight deck primary and standby temperature control.
- FWD CAB or AFT CAB indicates duct temperature overheat.
- During Master Caution light recall:
- CONT CAB indicates failure of the flight deck primary or standby temperature control.
- Either FWD CAB or AFT CAB indicates failure of the associated zone temperature control.
- Lights will extinguish when Master Caution is reset.
Explain the meaning of an illuminated OFF SCHED DESCENT light.
The airplane descended before reaching the planned cruise altitude set in the FLT ALT indicator.
Note: 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 inputs. If the FLT ALT indicator is changed, the automatic abort capability to the original takeoff field elevation is lost.
Recall the function of the TRIM AIR Switch.
ON – trim air pressure regulating and shutoff valve signaled open.
OFF – trim air pressure regulating and shutoff valve signaled closed.
Recall the function of the RECIRC FAN.
NORM – normal cooling supply fan activated.
ALT – alternate cooling supply fan activated.
Explain the function of the (Equipment) EQUIP COOLING SUPPLY Switch.
NORM – normal cooling supply fan activated.
ALT – alternate cooling supply fan activated.
Explain the function of the (Equipment) 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 fan.
Selecting the alternate fan should restore airflow and extinguish the OFF light within approximately 5 seconds.
Describe the meaning of an illuminated DUAL BLEED Light.
Illuminated (amber) – APU bleed air valve open and engine No. 1 BLEED air switch ON, or,
No.2 BLEED air switch ON, APU bleed air valve and isolation valve open
Note: The DUAL BLEED light indicates that the air panel is configured 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 Number 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.
Describe the function of the Engine BLEED Air Switches.
OFF – closes the engine bleed air valve.
ON – opens the engine bleed air valve when engines are operating.
Describe the function of the APU BLEED Air Switch.
OFF – closes APU bleed air valve.
ON – opens the APU bleed air valve when APU is operating.
Explain the function of the Air Conditioning 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.
