Airborne Weather Radar

Question 1

Frequency band and wavelength of AWR

Answer 1

SHF - 9GHz
3cm (ideal for detecting wet hailstones)

Question 2

How is the AWR stabilised

Answer 2

Using the ac attitude reference system

Question 3

Radiation pattern of AWR

Answer 3

Conical/Pencil (cone shapes beam)
Beam width 3 degrees to 5 degrees

Question 4

Functions of the AWR

Answer 4

Weather Mode - Black/Green/Amber/Red/Magenta

WX/Turb Mode - Doppler shift (infer turbulence)

MAP mode - Black (water) Green (Land) Amber (high ground)

Question 5

AWR - Gain control

Answer 5

Sensitivity
High gain = smaller water droplets detected

Too high - unnecessary weather avoidance
Too low - severe weather being missed.

Question 6

Mapping Mode

Answer 6

Used to display ground features of 150nm or more

Question 7

Ground operations of AWR

Answer 7

Short microwave make it dangerous
Switch off when not on runway

Question 8

Take off/climb with AWR

Answer 8

Tilt radar along flight path - 4 degree up

Question 9

AWR - In the cruise

Answer 9

Tilt angle slightly down as upper part of cloud is mainly ice
Not too low for ground returns

Question 10

AWR - Descent and approach

Answer 10

Lower tilt to scan down descent path
Reduce tilt as you get lower to reduce ground returns
Set 4 degrees up on approach to avoid ground clutter

Question 11

Heaviest turbulence will be encountered when looking at AWR

Answer 11

Max where there is the highest gradient in colour change or the thinnest part of the storm cell wall as both down current and up current will be encountered

Question 12

Using mapping modes in polar areas run risk of

Answer 12

Mistaking edge of costal ice off shore for the real coastline

Question 13

How does AWR detect wind shear

Answer 13

Doppler shift to detect relative velocity of water droplets a short distance ahead of ac

Question 14

Azimuth marker lines and range lines - AWR

Answer 14

Give the relative bearing and distance to a thunderstorm on the screen

Question 15

W/X+T Mode

Answer 15

Shows all weather ahead of aircraft plus any turbulent air masses

Question 16

To avoid blind alley you must

Answer 16

Increase the range scale

Question 17

Decreasing the range on the radar screen you would see

Answer 17

An increase in area and the returns moving to the top of the screen

Question 18

WX+T mode displays

Answer 18

Turbulence within precipitation by detecting the Doppler shift of reflect radar signal (NOT FALLING DROPLETS ONLY HORIZONTAL MOVEMENT)

Question 19

AWR can be used to determine the aircraft’s position by

Answer 19

Using the mapping mode to obtain a relative bearing and distance from the aircraft to suitable echoes on the display

Question 20

Heaviest turbulence is likely to be encountered

Answer 20

In areas of heaviest precipitation closest to the edge of the thunderstorm cell