CHAPTER 20 · AME TRAINING MODULE

WEATHER
RADAR

WXR SYSTEMS · AIRCRAFT MAINTENANCE ENGINEERING
20.1 SYSTEM OVERVIEW 20.2 AIRBORNE EQUIPMENT ANTENNA TRANSCEIVER DISPLAY 20.3 PRECIPITATION TURBULENCE HAILSTONES WIND SHEAR QUIZ CHECKPOINTS
◈ WXR-20 TRAINING SIM
C-BAND
ANTENNA OK
TRANSCEIVER OK
MODE: WEATHER
RANGE: 320 NM
LESSON 1 / 12
KEY CONCEPT
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PPI DISPLAY STORM PRECIP ◀ 320 NM RANGE ▶ BLACK GREEN YELLOW ORANGE RED MAGENTA RAINFALL RATE ✈ NOSE CONE FLAT-PLATE ANTENNA PLANAR ARRAY TYPE EQUIPMENT BAY XCVR 1 XCVR 2 2× TRANSCEIVERS WAVEGUIDE CUMULONIMBUS (Cb) — ANVIL TOP HAILSTONES (up to 60mm) UPDRAFT DOWNDRAFT ✈ PENCIL BEAM — SCANNING AHEAD RAYLEIGH SCATTERING Return ∝ Droplet diameter⁶ Larger drop = Stronger return ① CUMULUS STAGE ~20 MIN Warm moist air rises Moisture condenses Latent heat released 15,000 ft ② MATURE STAGE ANVIL Up to 40 MIN Max turbulence Lightning + hail 50,000 ft ③ DISSIPATING Updraughts weaken Downdraughts dominate Cell collapses Cooling + Dissipating ⚠ WIND SHEAR: Opposite air masses create turbulence — basis of WXR turbulence detection MICROBURST ✈ (A) APPROACHING HEADWIND ↑ LIFT ↑ AIRSPEED ✈ (B) EXITING TAILWIND ↓ LIFT ↓ AIRSPEED DOPPLER SHIFT DETECTION Droplets (A) → Higher freq return Droplets (B) → Lower freq return Freq difference = Wind shear warning C-BAND 4 – 8 GHz Wavelength: ~37.5 mm ✓ Penetrates heavy precipitation ✓ Better weather detection ✓ Larger antenna → more power ✗ Larger antenna size required ✗ Lower image resolution USED ON: SMALLER AIRCRAFT WIDER BEAM X-BAND 8 – 12.5 GHz Wavelength: ~25 mm ✓ Higher image resolution ✓ Smaller antenna required ✗ Weather avoidance only ✗ Cannot penetrate heavy rain USED ON: LARGE PASSENGER JETS NARROWER BEAM VS ✈ FAN-BEAM MODE: TERRAIN MAPPING RIVER MOUNTAIN COASTLINE GAIN CONTROL Too low → unclear image Too high → image saturated Optimum → clear display SECONDARY USE OF WXR Rivers · Coastlines · Mountains Selected on control panel by crew ◈ WEATHER RADAR TRAINING SIMULATOR · WXR-20

SYSTEM STATUS

ANT
ANTENNA
XCVR
TRANSCEIVER
PPI
DISPLAY

OPERATING PARAMETERS

C/X
FREQ BAND
320NM
RANGE
0°
TILT

TRANSMITTER POWER

4 GHz5–10 kW12.5 GHz
MODEWEATHER
SCAN WIDTH±90°
PULSE RATENORMAL
TARGETPRECIP
HAZARD LEVELLOW
◈ LESSON BRIEFING
Initializing weather radar training...
LESSON 1 OF 12
SCORE: 0/4
Question...

✈ TRAINING COMPLETE

You have successfully completed the Chapter 20 Weather Radar module. All 12 lessons and 4 knowledge checks passed. You are now cleared to work on weather radar systems!

0/4QUIZ SCORE
12LESSONS
320 NMRANGE
WXR-20MODULE