Vayudoot Aviation

1. In Airborne Weather Radar (AWR) the main factors that determine whether or not a cloud will be detected are?

Size of the water droplets and the diameter of the radar scanner.

Range to the cloud, wavelength/frequency used.

Size of the water droplets, and the wavelength/frequency used.

Rotational speed of the radar scanner, range from cloud.

2. Airborne weather radar system use a wavelength of approximately 3 cm in order to

Detect the smaller cloud formations as well as large.

Obtain optimum use of the Cosecant squared beam.

Detect the larger water droplets.

Transmit at a higher pulse repetition frequency for extended range.

3. A side lobe from an aerial of a weather radar may produce an echo on the screen known as a "height ring". The pilot can use this?

As a range marker.

To determine that the weather radar is functioning.

To determine the aeroplane's height above the surface.

As a zero point for range measurement.

4. In an Airborne Weather Radar that has a colour cathode ray tube (CRT) increasing severity of rain and turbulence is generally shown by a change of colour from

Green to red to black.

Yellow to amber to blue.

Yellow to orange to red.

Green to yellow to red.

5. When using the AWR to detect long range ground features the most suitable mode of operation or beam selected would be?

The mapping mode.

The contour mode.

The manual mode.

The fan shaped beam.

6. The ISO-ECHO facility of an airborne weather radar is provided in order to

Detect areas of possible severe turbulence in cloud.

Extend the mapping range.

Inhibit unwanted ground returns.

Give an indication of cloud tops.

7. Which statements relating to the stabilization system of airborne weather radar antennae is true?

The are stabilized with respect to the yaw axis, but not with respect to the pitch and roll axes.

They are stabilized with respect to the pitch, roll and yaw axes.

The pilot can choose the axes of stabilization with the system's stabilization selector switch.

They are stabilized with respect to the pitch and roll axes but not with respect to the yaw axis.

8. Airborne Weather Radars are generally based on the use of?

Secondary radar in the VHF band.

Primary radar in the SHF band.

Secondary radar in the SHF band.

Primary radar in the UHF band.

9. The airborne weather radar (AWR) cannot detect?

Wet hail.

Snow.

Dry hail.

Moderate rain.

10. Before commencing a flight the weather radar should?

Be switched to stand-by, but not used until airborne.

Be switched to a range function after push-back to make sure it is functioning.

Not be switched on until clear of buildings.

Be kept at stand-by until line-up with the runway.

11. The "gain" control knob of an AWR adjusts?

The automatic gain control of the AWR is activated.

The receiver sensitivity in order to achieve optimum target acquisition.

The power level of the transmitted energy is made dependent on the selected range.

The brightness of the display.

12. Which of the following is a complete list of airborne weather radar antenna stabilisation axes?

Roll, pitch and yaw.

Pitch and yaw.

Roll and yaw.

Roll and pitch.

13. The main factors, which affect whether an AWR will detect a cloud, are?

The size of the water droplets and the wavelength/frequency.

The scanner rotation rate and the wavelength/frequency.

The size of the water droplets and the diameter of the antenna reflector.

The size of the water droplets and the range to the cloud.

14. When using airborne weather radar in the mapping mode in polar areas one runs the risk?

Of getting a distorted because of the ice reflections.

Of understmating distance because the cold seawater is causing super refraction.

Of aurora borealis (polar light) causing false returns.

Of mistaking the edge of coastal ice off shore for the real coastline.

15. In general the operation of airborne weather radar equipment on the ground is

Totally prohibited

Unrestrictedly permitted in aerodrome maintenance areas

Only permitted with certain precautions, to safeguard health of personnel and to protect equipment.

Permitted anywhere

16. Which of the following lists phenomena that CANNOT be detected by weather radar?

Snow; clear air turbulence

Snow; turbulence in clouds with preciptation.

Dry hail; clear air turbulence

Clear air turbulence; turbulence in cloud with precipitation

17. AWR in the __________ Mode progressively _________ As distances ___________ To equalise screen brightness?

Mapping, increases gain, decreases.

Mapping, decreases power, decreases.

Weather, decreases gain, increases.

Weather, increases power, decreases.

18. The pencil shaped beam of an airborne weather radar is used in preference to the mapping mode for the determination of ground features

When approaching coast-lines in polar regions

Beyond 150 NM because the wider beam gives better definition

Beyond 50 to 60 NM because more power can be concentrated in the narrower beam.

Beyond 100 NM because insufficient antenna tilt angle is available with the Mapping mode.

19. Is is possible for weather radar to be operated on the ground?

Yes, always.

No, never.

Only whilst taxling

Yes, if operating within regulations and guidelines.

20. In weather radar the use of a cosecant beam in 'Mapping' mode enables

A greater radar range to be achieved.

Higher definition echoes to be produced giving a clearer picture.

Better reception of echoes on contrasting terrain such as ground to sea.

Scanning of a large ground zone producing echoes whose signals are practically independent of distance.

21. The tilt angle on the AWR at which an active cloud just disappears from the screen is 4 degrees up. If the beam width is 5 degrees and the range to the cloud is 40 nm use the 1 in 60 rule to calculate the approximate height of the cloud relative to the aircraft?

6000 ft below.

6000 ft above.

4000 ft above.

4000 ft below.

22. On the AWR display the most severe turbulence will be shown?

By steep colour gradients.

By a black hole.

In flashing red.

Alternating red and white stripes.

23. The theoretical maximum range for an airborne weather radar is determined by the?

Carrier wave frequency.

Pulse length.

Beam width.

Pulse repetition frequency.

24. The cosecant squared beam is used for mapping in the AWR because?

It allows cloud detection to be effected while mapping.

A greater range can be achieved.

A larger area of ground is illuminated by the beam.

A wider beam is produce din azimuth to give a greater coverage.

25. The airborne weather radar uses the following wavelength?

Metric.

Myriametic.

Hectometric.

Centimetric.

26. In order to ascertain whether a cloud return on an Aircraft Weather Radar (AWR) is at or above the height of the aircraft, the tilt control should be set to? (Assume a beam width of 5°)

2.5° up.

2.5° down.

0°.

5° up.

27. In Airborne Weather Radar (AWR), the main factors which determine whether a cloud will be detected are

Size of the water droplets and the diameter of the scanner.

Size of the water drops and the wavelength/frequency used.

Rotational speed of radar scanner and the range from cloud.

Range from cloud and the wavelength/frequency used.

28. If the AWR transmitter is to be switched on before take-off the scanner should be tilted up with?

Either of the modes selected.

The mapping mode selected.

none of the above.

The weather mode selected.

29.
The pictures in the diagram are showing an aircraft's position with respect to some thunderstorm cells and the image the pilot is getting from the radar. To detect this "blind alley" the pilot should?

Switch over from normal to X mode.

Increase the range setting of the radar.

Initiate a steep climb.

Select the cosecant square beam fro better alley detection.

30. Weather radar is used by the pilot to assist in the?

Detection of other aircraft through clouds.

Detection and determination of a route through active cloud formations.

Detection and avoidance of potentially turbulent cloud cells.

Detection and avoidance of turbulence.

31. Airborne Weather Radar has been primarily developed to detect?

Areas of severe clear air turbulence.

The kinds of precipitation, which are usually accompanied by turbulence.

All kinds of frozen precipitation such as hail, snow and graupel.

Areas of wind sheer and severe aircraft icing.

32. In an Airborne Weather Radar the areas of greatest turbulence are usually indicated on the screen by?

Colour zones of red or magenta.

Blank areas where there is no colour.

Colour zones of green or yellow.

Areas which are coloured black.

33. In order to ascertain whether a cloud return on an Aircraft Weather Radar (AWR) is at or above the height of the aircraft, the tilt control should be set to (assume a beam width of 5 degrees)?

0 degrees.

5 degrees up.

2.5 degrees up.

2.5 degrees down.

34. On the airborne weather radar display in WX mode, different colours use used?

To display different intensity of precipitation.

To display clouds, indicating different levels of visibility.

To display ground height differences.

To display echoes from other aircraft.

35. In which mode of operation does the aircraft weather radar use a cosecant radiation pattern?

MAPPING

CONTOUR.

MANUAL

WEATHER

36. A height ring is used?

As a zero point for range measurement.

To determine that the weather radar is functioning.

To determine the exact aeroplane height above the surface.

As a range marker.

37. An aircraft flying at 25 00 feet is equipped with AWR. The beam width is 5 degrees. With the radar tilted 3.5 degrees up, the radar is showing top of a cloud return at 105 nm. The approximate height of the cloud is

14 300 ft.

30 300 ft.

25 600 ft.

35 600 ft.

38. In an Airborne Weather Radar that has a colour cathode ray tube (CRT) the areas of greatest turbulence are indicated on the screen by

Colour zones being closest together.

Blank iso-echo areas where there is no colour.

Iso-echo areas, which are, coloured black.

Large areas of flashing red colour.

39. Which of the following cloud types is most readily detected by airborne weather radar when using the weather beam?

Altostratus

Cumulus.

Stratus.

Cirrocumulus.

40. Airborne weather radar uses a particularly high frequency radar signal, at 9 to 12 GHz, in order to?

Al of the answers in this question are correct.

Get good returns from droplets of water and other sorts of precipitation.

Get the most accurate range and bearing inforation.

Make it possible to present a colour display of the weather situation.

41. When the airborne weather radar is operating in its primary mode, to detect precipitation?

Maximum tilt on the aerial will often be used.

The radar beam is a cosecant beam.

The radar beam is pencil shaped.

The range will be limited, compared to the range obtainable in the ground mapping mode.

42. An airborne weather radar is using a 3 degrees beam. A cloud is detected at a range of 40 nm, If the scanner is tilted up to 3 degrees the cloud disappears. The top of the cloud, in relation to the aeroplane's cruising level is approximately?

At the same level.

6000 ft above the level.

18000 ft above the level.

12000 ft above the level.

43. An airborne weather radar unit transmits a 5 degrees beam from a parabolic dish aerial reflector assembly. If the wavelength is 4 cm, the diameter of the dish is?

87.5 cm

20 cm.

87.5 in.

56 cm.

44. On a weather radar, the greatest turbulence is likely in an area where targets are?

Coloured magenta.

Coloured red.

Show a rapid gradient of change from magenta to yellow.

Show a clearly defined hole.

45. An airborne weather radar unit transmits a 4 degrees beam from a parabolic dish aerial reflector assembly. If the wavelength is 3 cm, the diameter of the dish is?

20 in.

20 cm.

52.5 in.

52.5 cm.

46. A weather radar, set to the 100 NM scale, shows a squall at 50 NM. By changing the scale to 50 NM, the return on the radar screen should

Increase in area and move to the top of the screen

Increase in area and appear nearer to the bottom of the screen

Decrease in area but not change in position on the screen.

Decrease in area and move to the top of the screen

47. In an AWR with a 5 degrees beam width how do you orient the scanner to receive returns from clouds that are at or below your level?

2.5 degrees up tilt.

0 degrees tilt.

2.5 degrees down tilt.

5 degrees down tilt.

48. The ISO-ECHO feature of an airborne weather radar can be used to detect?

CAT

Wake turbulence.

Turbulence in cloud.

Areas of possible turbulence is cloud.

49. The stabilisation of the weather radar aerial is effective?

For up to +/- 30 degrees of combined pitch and roll.

For up to +/- 20 degrees of combined pitch and roll.

For up to +/- 5 degrees in pitch and roll.

For up to +/- 40 degrees of combined pitch and roll.

50. Ground checks of AWR are?

Allowed under specific health and safety regulations.

Prohibited at all times.

Unrestricted.

Allowed only when the aircraft has undergone major servicing.

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