AS 07 - Radar Theory 2 & Weather Avoidance

Question 1

Review Questions

Name the basic radar components

Answer 1

A - Antenna
P - Power Supply
R - Receiver
I - Indicator
S - Synchronizer 
M - Modulator
T - Transmitter

Question 2

What are some radar reception factors?

Think target, pulse and radar

Answer 2

Target range, size, shape, reflectivity characteristics
Pulse shape, width and repetition frequency (PRF)
Radar power output and receiver sensitivity

Question 3

Why do smooth seas appear black on the scope?

Answer 3

Very little energy returns to the radar, most is lost due to reflection

Question 4

As seas become rougher, waves produce small reflecting surfaces that return _____ radar energy to the receiver and the scope becomes brighter. How does this effect small targets on the radar?

Answer 4

More

Small targets may be hard to identify.

Question 5

To overcome sea return interference, an operator can:

Reduce_____
Reduce _____
_____ antenna tilt
Select _____ mode

Answer 5

Reduce gain
Reduce altitude
Raise antenna tilt
Select sea mode

Question 6

Surface vessels resemble what land mass?

Answer 6

Islands

Question 7

Metal or concrete boats will provide what when compared to wooden boats?

Answer 7

Stronger radar returns

Question 8

If rivers are wide, they show up dark. The far shore of a river or lake will appear much _______ than the far shore.

Answer 8

Brighter

Question 9

A narrow river may be identified solely by what on radar?

Answer 9

A bright return from the far bank

Question 10

WRT aspect, a river will give more returns if you are __________ to river

Answer 10

Perpendicular

Question 11

Mountains block off the radar echoes and cause what?

Answer 11

A mountain shadow

Question 12

True or false

As the aircraft passes over a mountain, the near edge of a mountain appears brighter than the far edge.

Answer 12

True

Question 13

If no returns are shown from behind the bright mountain, its possible the aircraft may be _____ the peak.

Answer 13

Below

Question 14

If returns do show up behind the bright mountain return, the AC may be above the peak or what?

Answer 14

There may be another mountain peak beyond the first

Question 15

What topo/ geographical features may be mistaken for rivers on a radar?

Answer 15

Valleys or canyons

Question 16

Do urban areas provide good or bad radar returns, why?

Answer 16

Good radar returns because buildings are very good reflectors due to shape and materials.

Question 17

The layout of urban areas creates what kind of effect?

Answer 17

A cardinal effect, towns often lined up N-S / E-W

Question 18

What are the Variable Limiting Factors?

Answer 18

Target size and shape
Target composition (reflectivity)

Question 19

Order the following from strongest to weakest return:

Wood, concrete, water, metal, earth, rock and ice

Answer 19

1. Metal
2. Concrete
3. Rock
4. Wood
5. Earth
6. Water
7. Ice

Question 20

What are the Constant Limiting Factors?

Answer 20

Radar Power 
PRF
Spot Size (the resolution of your display)
Pulse Width (range resolution)
Beam Width (azimuth resolution)
Combined Errors

Question 21

On the Hercules and Cyclone, the ACSO is primarily responsible for operating what? As well, the ACSO is responsible for _______ avoidance when operating IFR conditions or at night.

Answer 21

The radar & weather avoidance

Question 22

What does the Weather Radar System present and display?

Answer 22

It presents an accurate and continuous picture of the weather ahead of the AC

It displays range and azimuth, enabling the operator to give heading changes to avoid severe weather.

Question 23

The radar “sees” water droplets. What affects the strength of radar return regarding water droplets?

Answer 23

The intensity of the return depends on the size of droplets and their concentration.

Question 24

The close relationship between turbulence and rain gradient explains what exactly?

Answer 24

The greater the change (increase) in water content, the more severe the turbulence.

Question 25

True or false The primary aim is to avoid areas of heavy rain.

Answer 25

False, The primary aim is to avoid areas of heavy turbulence, hail rather and areas of heavy rain

Question 26

Which stage of a thunderstorm has the greatest turbulence?

Answer 26

Mature stage, this is when up and down drafts occur with rapid changes in direction and velocity

Question 27

How are up and down drafts depicted on the radar?

Answer 27

A sharp edged echo due to high rain gradient

Question 28

What level of relfectivity does snow have?

Answer 28

Light, even moderate - heavy snowfall can appear light in intesnsity

Question 29

Hail and ice pellets can appear as which type of precipitation?

Answer 29

Heavy precipitation

Question 30

Which side of the thunderstorm anvil is the most dangerous? Why?

Answer 30

The downwind side (under the anvil) because hail may be encountered several miles from the strongest radar returns while underneath.

Question 31

Which factors make hail difficult to detect?

Answer 31

The shape, density and intensity may give varying levels of returns

Question 32

Radar returns that resemble pointed fingers or hook indicate what? (review this question, I think TS is an answer)

Answer 32

The potential for hail, and in some cases, tornadoes

Question 33

A rapidly developing storm is indicated on a radar by?

Answer 33

Scalloped lines or rapidly changes edges. Avoid at greater distances

Question 34

True or false Whenever possible you should maintain your track to fly through the heaviest radar returns.

Answer 34

False, avoid these areas by altering course to fly between or around.

Question 35

What are the weather avoidance distances for the different levels?

Answer 35

5 NM when flying below freezing level 10 NM when flying above freezing level 20 NM when flying above 30 000'

Question 36

What are the weather options for the AN/APS 504 (V) 3?

Answer 36

Weather (WX) and Weather Contour (CTR)

Question 37

Briefly describe WX and CTR modes.

Answer 37

WX mode provides signal processing to show areas of strongest returns within a cell. CTR mode suppresses areas of high precipitation in the display to give a brightly outlined weather display. The strongest parts of the storm cloud appear as black holes in the cloud returns.

Question 38

For the best results with Weather Mode, how should antenna tilt be adjusted?

Answer 38

Adjusted to a point just above the ground clutter returns to avoid confusing ground and weather returns.

Question 39

Review Questions Why are urban areas good radar targets?

Answer 39

Buildings are very good reflectors due to their shape. | Towns often lined up N-S / E-W creating a cardinal effect.

Question 40

Review Questions Why doesn't hail show on the radar?

Answer 40

It is made out of ice which is a poor reflector unless coated in liquid water.

Question 41

Review Questions What are the distance rules for avoiding storm clouds?

Answer 41

5 NM below freezing level 10 NM above freezing level 20 NM above 30 000'