.
altitude deviation less than 250 feet, or

.
altitude deviation more than 750 feet, or

.
new MCP altitude selected.

Copyright . The Boeing Company. See title page for details.
15.10.4   June 4, 2004

Warning Systems -Controls and Indicators 737 Operations Manual
GPWS Controls and Indicators
PULL UP 
BELOW G/S P-INHIBIT 

PULL UP WARNING LIGHT
Illuminated (red) – indicates one or more of the following exist:
.
excessive descent rate

.
excessive terrain closure rate

.
altitude loss after takeoff or go–around

.
unsafe terrain clearance when not in the landing configuration

BELOW Glide Slope (G/S) Alert Light
Illuminated (amber) – airplane is more than 1.3 dots below glide slope.
Warning Systems -Controls and Indicators

737 Operations Manual
Push – inhibits or cancels below glide slope alerting if pushed while in alerting area.

GPWS Inoperative (INOP) Light
Illuminated (amber) – GPWS computer malfunction or power loss
.  invalid inputs are being received from radio altimeter, ADC, ILS receiver,
IRS, FMC, stall warning system, or EFIS control panel.

Ground Proximity System (SYS TEST) Switch
Push –
.
momentarily on ground, or above 1,000 feet radio altitude in flight:

.  illuminates BELOW G/S, PULL UP, and INOP lights; displays the EADI WINDSHEAR message; and causes “GLIDESLOPE”, “WHOOP, WHOOP, PULL UP”, and “WINDSHEAR” aurals to sound

.  
at least 10 seconds, on ground – above indications always occur first,
followed by any additional aurals, as installed

.
system test is inhibited from lift–off to 1000 feet radio altitude.

GROUND PROXIMITY Flap Inhibit Switch
FLAP INHIBIT – inhibits or cancels warnings/alerts caused by flaps not in 30 or 40 position.
NORMAL (guarded position) – flap position logic is provided for GPWS.

GROUND PROXIMITY Gear Inhibit Switch
GEAR INHIBIT – inhibits or cancels warnings/alerts caused by landing gear not down.
NORMAL (guarded position) – landing gear position logic is provided for GPWS.

GROUND PROXIMITY Switch
FLAP/GEAR INHIBIT – inhibits or cancels warnings/alerts caused by flaps not in 30 or 40 position or landing gear not down.
NORMAL (guarded position) – flap and landing gear position logic is provided for GPWS.
Copyright . The Boeing Company. See title page for details.
15.10.6   December 1, 2000

Warning Systems -Controls and Indicators 737 Operations Manual
EGPWS Controls and Indicators
PULL UP 
BELOW G/S P-INHIBIT 

PULL UP Warning Light
Illuminated (red) – Indicates that one or more of the following conditions exists:
.
excessive descent rate

.
excessive terrain closure rate

.
altitude loss after take-off or go-around

.
unsafe terrain clearance while not in landing configuration

.
terrain or obstacle warning.

Below Glide slope Alert Light
Illuminated (amber) – Indicates that aircraft is more than 1.3 dots below glideslope Push - inhibits or cancels below glideslope alerting if pushed while in alerting area

Ground Proximity Inoperative [INOP] Light
Illuminated (amber) – GPWS computer malfunction or power loss: invalid inputs are being received from radio altimeter, ADC, ILS receiver, IRS, FMC, stall warning system or EFIS control panel.
Warning Systems -Controls and Indicators 737 Operations Manual

GPWS System Test [SYS TEST] Switch
Proper operation of the Enhanced Ground Proximity Warning System may be
verified when the aircraft is on the ground as follows: Ensure that the TERR INHIBIT switch is set to NORM, WXR (EHSI Control Panel) is ON, Weather Radar is in TEST mode, and EHSI selected to a mode which allows the display of weather radar information (EXP NAV, EXP VOR/ILS, MAP, or CTR MAP): Momentarily push the Ground Proximity SYS TEST switch –
.  
amber Ground Proximity INOP light and Terrain Display Select INOP lights illuminate

.
amber BELOW G/S lights illuminate

.
aural GLIDESLOPE message is annunciated

.
amber BELOW G/S lights extinguish

.
red PULL UP lights illuminate

.
aural PULL UP message is annunciated

.
red PULL UP lights extinguish

.  
siren and aural WINDSHEAR, WINDSHEAR, WINDSHEAR
message is annunciated