B737Cl Lights & Switches (Aft Overhead)

Front 1

APU HOUR METER

Back 1

Indicates the total APU operating time since the last reset.

Front 2

LED
LE FLAPS: Consists of the two inboard panels. They will fully extend at flaps 1 and the green extend lights will illuminate.

Back 2

LE SLATS: Consists of the three outboard panels. They will move to the 'EXTEND' position at TE flaps position 1-5, and the three middle green lights will illuminate. Aft of position 5 the LE slats move to the 'FULL EXTEND' position, and the aft three green lights will illuminate.

Hint 2

TRANSIT: Indicates the respective leading edge device is in transit.

When each device is fully retracted, the associated transit light will be off.

TEST: This switch tests all the LE DEVICES lights on the annunciator panel.

Front 3

IRS
TEST:
+ Tests IRS DISPLAY UNIT lights and number displays.

+Initiates a ten second self test.

LEFT OR RIGHT: Selects the left or right IRU for display data.

Back 3

TK/GS: Displays true ground track on the left and ground speed on the right.

PPOS: Displays current latitude and longitude.

Hint 3

WIND: Displays current true wind direction on the left and current wind speed on the right.

HDG/STS:
+Displays true heading on the left and any malfunction status codes on the right.

+Displays minutes remaining until alignment completion beginning at 7 minutes.

Front 4

ENT KEY: Both green cue lights illuminate when alphabet keys are pressed. When ENT key is pressed, cue lights extinguish and data is entered to both IRU's.

Back 4

CLR KEY:
+If data entered is not acceptable to the IRU, both green cue lights illuminate. Pushing the CLR key will delete the unacceptable data.
+The CLR key can also be used to erase data entered prior to pushing the ENT key.

ALPHABET KEYS: Allows control of the data display and arms the display unit for numeric entries.

NUMERIC KEYS:
+Permits manual entry of present position when in the

Hint 4

ALPHABET KEYS: Allows control of the data display and arms the display unit for numeric entries.

NUMERIC KEYS:
+Permits manual entry of present position when in the ALIGN mode.
+Allows entry or mag heading when either mode select switch is in ATTITUDE.

Front 5

IRS MODE SEL UNIT ALIGN
ON STEADY:
+IRU aligning when in the ALIGN, NAV, or ATT positions.
+In a 30 second shutdown mode if mode selector is OFF.
ON FLASHING: Alignment fault due to the following.
+Airplane movement during alignment process.
+10 minutes has expired without entering present position.
+Significant distance between last position at shutdown and entered position.
+An unreasonable entry
OFF:
+The alignment is complete, and the IRU is providing data to respective systems.
+The IRS mode selector is off.

Back 5

ONDC
The associated IRS is operating on the Hot Battery Bus due to a lack of AC power.
MODE SELECT switch has been placed in ALIGN, NAV, or ATT from the off position and the IRS is testing the backup DC source of power for 5 seconds.

Hint 5

FAULT
A fault exists with the respective IRS.
DCFAIL
Backup DC power source is not available to the respective IRU.

If normal AC power is available, IRU will operate normally.
DC FAIL lights will illuminate if the battery voltage less than 18 volts.

Front 6

OFF: Shuts down the associated IRU after a 30 second shutdown mode.
ALIGN:
+IRU initiates a 10 minute alignment mode.
+When placed to ALIGN from NAV, will accomplish IRS fast alignment.

Back 6

NAV: Data provided to associated systems after a 10 minute alignment process. Alignment can be accomplished by moving the selector to the NAV mode rather than ALIGN.

Hint 6

ATT: Will display attitude and heading information to the associated ADI, HSI, and opposite RDMI. Heading must be manually entered by pushing the H key on the IRS DISPLAY UNIT. Navigation data is not available.

Front 7

DOMELIGHT

Back 7

Controls two overhead dome lights above the captain and first officer.

Front 8

ENG PANEL REVERSERS
Reverser sleeves are asymmetrical. One stowed and the other one un-stowed. REVERSER UNLOCKED light on the center instrument panel also illuminates.

Back 8

Comes on when the reversers are commanded to stow, and will extinguish after approximately 10 seconds when the isolation valve closes.

Hint 8

Illuminates if the isolation or selector valves are not in their commanded positions.

Illuminates when the reverser is in transit.

Front 9

PMC CONTROL SWITCHES:
ON: Switch is selected on and the PMC is armed for operation at or above 46% N2 RPM.

Back 9

OFF: Indicates the PMC switch is selected off. De-energizes the PMC so the MEC controls engine operation.

Hint 9

PMC INOP LIGHTS: The PMC has detected an internal fault, or the PMC CONTROL switch has been placed off.

Front 10

LOW IDLE
Illuminates for the following reasons:
+One or both engines are in low idle when they should be in high idle.

Back 10

+The speed of either engine is below 25% N1 in flight.

Hint 10

+As applicable, an engine start switch is in FLT and one or both engines are operating at or below 45% N1 above 500 ft AGL.

Front 11

OXY PANEL
Indicates crew oxygen pressure upstream of the oxygen shutoff valve.
Power to gauge is from the BATTERY BUS.

Back 11

NORMAL: Passenger oxygen system armed for automatic operation when cabin altitude reaches 14,000 feet.
ON: Manually activates the passenger oxygen system.

Hint 11

Passenger oxygen system is activated.

Front 12

FLIGHT RECORDER PANEL
TEST: Allows flight recorder operation without the engines running.
NORMAL: Recorder operates whenever either engine is running or in flight, regardless of engine operation.

Back 12

Power is off or a tape malfunction exists.
Tests the associated

MACH/AIRSPEED warning system, and the airspeed clacker sounds.

Hint 12

STALL WARN TEST
Tests the associated stall warning computer and the associated stick shaker.