Boeing 747: Air Conditioning

747 Air Conditioning by jerome meriweather
	AFT OverHead Glareshield Forward Pedestal
Up to Pressurization Left to Fuel Start Down to Pneumatic To View a Control's Description, MouseOver it and ... Click to "Show" - MouseDown to "Drag" - DoubleClick to "Hide"

747 Photo and/or Graphic Element

HUMID Switch

Gasper Switch

PACK RST Switch

When pushed, resets pack in system fault mode, if fault no longer exists.
Resets pack fault protection system.
Restarts pack after automatic shutdown if fault no longer exists.
Resets recirculation fan logic and restarts recirculation fans if fault no longer exists.
SYS Fault Light - Indicates a pack overheat or other pack fault has occurred.

HI Flow Switch

EQUIP Cooling Selector

NORM- Prior to engine start and based on OAT, cooling air is exhausted overboard or into the forward cargo compartment.
- With two engines running, equipment cooling air is exhausted into forward cargo compartment and the ground exhaust valve closes.
- With single internal fault, equipment cooling valves close to allow internal circulation of cooling air.
STBY- Same as NORM, except:
- Ground exhaust valve closes and inboard exhaust valve opens.
- Bypasses automatic control to configure system for flight.
OVRD
- Inboard exhaust valve closes.
- Ground exhaust valve closes.
- Equipment supply valve closes.
- Smoke/override valve opens.
- Differential pressure exhaust cooling air overboard.

AFT Cargo Heat Switch

ON - Overheat shutoff valve opens to provide bleed air to the AFT Cargo compartment.
OFF - Shuts off all bleed air to the AFT Cargo compartment
TEMP Light - AFT Cargo compartment temperature excessive.

Fan Switches

Trim AIR Switch

ON - Master Trim AIR valve opens and zone regulating valves operate automatically.
OFF
- Master Trim AIR valve closes.
- Pack output temperature is regulated to provide an average cabin temperature of 75°F.
- EICAS advisory message TRIM AIR OFF is displayed.
- Flight Attendant control of zone temperature is inhibited.

Zone RST Switch
Resets zone temperature controller if fault no longer exists.

SYS Fault Light
- Illuminated indicates zone duct overheat or another zone temperature controller fault has occurred.
- Master trim air valve has failed closed.
- Trim air switch OFF.

Passenger & Flight Deck Temperatures

AUTO
- Provides automatic control of passenger zone temperature.
- Sets master temperature for all zones.
- Selectors range is 65°F - 85°F.
ALTN
- Zone trim air valves remain in last positive.
- Pack outlet temperature regulated to provide an average cabin temperature of 75°F or 85°F in the warmest zone.
- Flight Attendant control of zone temperature is inhibited.