PACK TRIP OFF Light
Illuminated (amber) –
.
indicates pack temperature has exceeded limits
.
related pack valve automatically closes and mix valves drive full cold
.
requires reset.
TRIP RESET Switch
PUSH (if fault condition is corrected) –
.
resets BLEED TRIP OFF, PACK TRIP OFF and DUCT OVERHEAT
lights
.
lights remain illuminated until reset.
Equipment Cooling Panel
Equipment (EQUIP) COOLING SUPPLY Switch NORMAL – normal cooling supply fan activated. ALTERNATE – alternate cooling supply fan activated.
Equipment Cooling Supply OFF Light
Illuminated (amber) – no airflow from selected cooling supply fan.
Air Systems -Controls and Indicators 737 Operations Manual
Equipment (EQUIP) COOLING EXHAUST Switch NORMAL – normal cooling exhaust fan activated. ALTERNATE – alternate cooling exhaust fan activated.
Equipment Cooling Exhaust OFF Light
Illuminated (amber) – no airflow from selected cooling exhaust fan.
Cabin Altitude Panel
CABIN Altitude (ALT)/Differential Pressure (DIFF PRESS) Indicator
Inner Scale – indicates cabin altitude in feet.
Outer Scale – indicates the difference between cabin pressure and ambient pressure in psi.
CABIN Rate of CLIMB Indicator
Indicates cabin rate of climb or descent in feet per minute.
Copyright . The Boeing Company. See title page for details.
2.10.6 December 7, 2001
Air Systems -Controls and Indicators 737 Operations Manual
Altitude (ALT) HORN CUTOUT Switch
PUSH –
.
cuts out intermittent cabin altitude warning horn
.
altitude warning horn sounds when cabin reaches 10,000 feet altitude.
Cabin Pressurization Panel (Airplanes with CPCS)
FORWARD OVERHEAD PANEL
AUTO FAIL Light
Illuminated (amber) – automatic pressurization control failure. Control automatically transfers to the standby mode.
OFF Schedule (SCHED) DESCENT Light
Illuminated (amber) – airplane descended before reaching the planned cruise altitude set in the FLT ALT indicator.
Air Systems -Controls and Indicators 737 Operations Manual
Flight Altitude (FLT ALT) Indicator
.
indicates selected cruise altitude
.
set before takeoff.
Flight Altitude Selector
Push/rotate to set planned cruise altitude.
Landing Altitude (LAND ALT) Indicator
.
indicates altitude of intended landing field
.
set before takeoff.
Landing Altitude Selector
Rotate to select planned landing field altitude –
.
large diameter control sets 1000 foot increments
.
small diameter control sets 10 foot increments.
MANUAL Light
Illuminated (green) – pressurization system operating in the manual mode.
STANDBY Light
Illuminated (green) – pressurization system operating in the standby mode.
Cabin Rate Selector
.
DECR – cabin altitude rate of change equals 50 ft/min
.
INCR – cabin altitude rate of change equals 2000 ft/min
.
Index – cabin altitude rate of change equals 300 ft/min.
Outflow VALVE Position Indicator
. indicates position of outflow valve
. operates in all modes. Note: Indicator moves to the full left position when no AC power is available.
Outflow Valve Switch (spring–loaded to center)
CLOSE – closes outflow valve electrically with pressurization mode selector in
MAN position.
OPEN – opens outflow valve electrically with pressurization mode selector in
MAN position.
Copyright . The Boeing Company. See title page for details.
2.10.8 December 7, 2001
Air Systems -Controls and Indicators 737 Operations Manual
Cabin Altitude (CAB ALT) Indicator
.
Indicates selected cabin altitude
.
Set before takeoff.
Cabin Altitude Selector
Rotate to select desired cabin altitude
.
large diameter control sets 1000 foot increments
.
small diameter control sets 10 foot increments.
Pressurization Mode Selector
AUTO – pressurization system controlled automatically
STBY – pressurization system controlled through the standby mode
MAN –
.
pressurization system controlled manually by Outflow Valve Switch
.
AC – outflow valve operates from AC power
