GAIN Control
Rotate – sets gain in WX, WX+T and MAP modes.

TILT Control
Rotate clockwise – radar antenna tilts up to selected degrees from horizon.
Rotate counterclockwise – radar antenna tilts down to selected degrees from horizon.
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Flight Management, Navigation -Controls and Indicators 737 Flight Crew Operations Manual
YC153, YC154

Weather Radar Mode Switches
Push – selects mode. Left mode switches control the Captain’s radar display, right mode switches control the First Officer’s radar display.
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WX/T (turbulence) – shows weather radar returns and turbulence.
Turbulence display is available on displays of 40 nm or less.

Note:  Turbulence detection requires presence of detectable precipitation. Clear air turbulence cannot be detected by radar.

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WX – shows weather radar returns at selected gain level

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MAP – shows ground returns at selected gain level

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IDNT – suppresses ground return in WX and WX/T modes

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TFR (transfer) – transfers other map display selections to related map

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TEST –

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tests weather radar system operation without transmitting

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shows test pattern and any fault messages on navigation display MAP, center MAP, VOR, and APP modes, with WXR selected.

Note:  If the airplane is on the ground and the thrust levers are not advanced for takeoff, WXR tests the predictive windshear system (PWS) indications. These include PWS caution, PWS FAIL, and PWS warning. Deactivating WXR on the EFIS control panel will not discontinue the test and can result in automatic WXR activation on both pilot displays. The PWS test lasts approximately 15 seconds.

Gain Uncalibrated (UCAL) Lights
Illuminated – related gain control is in an uncalibrated position.

TILT Control
Rotate clockwise – radar antenna tilts up to selected degrees from horizon.
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Flight Management, Navigation -Controls and Indicators 737 Flight Crew Operations Manual

Rotate counterclockwise – radar antenna tilts down to selected degrees from horizon.

GAIN Control
Rotate – sets gain in WX, WX/T, and MAP modes.
CAL (calibrated) – gain is set to calibrated level in the full counterclockwise position.
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737 Flight Crew Operations Manual

Introduction
Navigation systems include the flight management system (FMS); global positioning system (GPS); air data inertial reference system (ADIRS); radio navigation systems (ADF, DME, ILS, marker beacons, and VOR); transponder; and weather radar.
YC153, YC154 Many of the flight instrument display symbols listed in this chapter also appear on the Heads Up Display (HUD) System. Refer to Chapter 10, Flight Instruments, for HUD system display symbol descriptions.
Flight Management System
The flight management system (FMS) is comprised of the following components:
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flight management computer system (FMCS)

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autopilot/flight director system (AFDS)

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autothrottle (A/T)

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inertial reference systems (IRS)

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global positioning system (GPS). Each of these components is an independent system, and each can be used independently or in various combinations. The term FMS refers to the concept of joining these independent components together into one integrated system which

provides continuous automatic navigation, guidance, and performance management.
The integrated FMS provides centralized flight deck control of the airplane’s flight path and performance parameters. The flight management computer, or FMC, is the heart of the system, performing navigational and performance computations and providing control and guidance commands.
YA686, YA687, YC153 - YK104 The primary flight deck controls are the AFDS MCP, two control display units (CDU’s), two electronic flight instrument system (EFIS) control panels, and an FMC source selector switch. The primary displays are the CDUs, outboard display units, inboard display units, and upper display unit.
YA613, YA626, YA721 - YA809 The primary flight deck controls are the AFDS MCP, two control display units (CDU’s), two electronic flight instrument system (EFIS) control panels. The primary displays are the CDUs, outboard display units, inboard display units, and upper display unit.
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Flight Management, Navigation -Navigation Systems Description