Vayudoot Aviation

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

Only whilst taxling

No, never.

Yes, always.

Yes, if operating within regulations and guidelines.

2. A frequency of 10 GHz is considered to be the optimum for use in airborne weather radar system because

The larger water droplets will give good echoes and the antenna can be kept relatively small.

Greater detail can be obtained at the more distant ranges of the smaller water droplets.

Static interference is minimised

Less power output is required in the mapping mode

3. An airborne weather radar, with a beam width of 4 degrees in azimuth, is being used in the mapping mode. At what maximum range will it be able to detect a 1 nm wide opening in a sea cliff?

45 nm.

4 nm.

15 nm.

60 nm.

4. 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.

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.

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

5. On a colour airborne weather radar, a bright red echo indicates?

An area of extreme turulence.

Heavy concentrations of liquid/solid water.

An area of strong windshear.

Strong rising air currents.

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

Blank areas where there is no colour.

Areas which are coloured black.

Colour zones of red or magenta.

Colour zones of green or yellow.

7. When switching on the weather radar, after start-up, a single very bright line appears on the screen. This means that the?

Scanner is not rotating.

Scanning of the cathode ray tube is faulty.

Transmitter is faulty.

Receiver is faulty.

8. 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 above.

6000 ft below.

4000 ft below.

4000 ft above.

9. 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.

10. The ISO-ECHO circuit is incorporated in the AWR?

To allow simultaneous mapping and detection of clouds.

To alert pilots to the presence of cloud.

To display areas of turbulence.

To allow ground mapping.

11. In the MAPPING MODE the airborne weather radar utilises a?

Fan shaped beam effective up to a maximum range of 50 nm to 60 nm.

Pencil beam effective from zero to 150 nm.

Pencil beam effective to a maximum range of 60 nm,

Fan shaped beam effective up to a range of 150 nm.

12. 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

Yellow to amber to blue.

Green to yellow to red.

Yellow to orange to red.

Green to red to black.

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

By steep colour gradients.

By a black hole.

Alternating red and white stripes.

In flashing red.

14. A frequency of airborne weather radar is

93.75 MHz.

9375 GHz.

9375 MHz.

9375 kHz.

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

Mapping, increases gain, decreases.

Weather, increases power, decreases.

Weather, decreases gain, increases.

Mapping, decreases power, decreases.

16. Airborne weather radars use a frequency of approximately 9 GHz because?

The wavelength is such reflections are obtained only from larger water droplets.

It has a short wavelength, so producing higher frequency returns.

The frequency penetrates cloud quite easily enabling good mapping of ground feature in the mapping mode.

The short wavelength allows signals to be reflected from cloud water droplets of all sizes.

17. The colours used on a conventional AWR to indicate increasing intensity of returns are?

Blue, Amber, Red.

Blue, Green, Red.

Green, Amber, Red.

Green, Yellow, Orange.

18. To improve the detection of precipitation area(s) in e.g. Thunderstorms, in which the top of the cloud lies at or slightly above the level of flight?

The tilting setting should be higher when the aircraft climbs to a higher altitude

The tilting setting should be lower when the aircraft climbs to a higher altitude.

The tilting setting should be lower when the selected range increase..

The tilting setting should be higher when the selected range decreases.

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

CONTOUR.

WEATHER

MANUAL

MAPPING

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

Permitted anywhere

Totally prohibited

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

Unrestrictedly permitted in aerodrome maintenance areas

21. The AWR can be used on the ground provided: 1. The aircraft is clear of personnel, buildings and vehicles. 2. The conical beam is selected. 3. Maximum up tilt is selected. 4. The AWR must never be operated on the ground

2, 3.

1, 2, 3.

4

1, 2.

22. 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.

0°.

5° up.

2.5° down.

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

Pitch and yaw.

Roll and pitch.

Roll, pitch and yaw.

Roll and yaw.

24. The airborne weather radar is using a 5 degree beam. The cloud is detected at a range of 60 nm. If the scanner is tilted up to 5 degrees, the cloud disappears. Using trigonometry to determine the height of the tops of the cloud, in relation to the aeroplanes cruising level, select the nearest answer from the following?

31900 ft below the aircraft.

31900 ft above the aircraft.

15900 below the aircraft.

15900 ft above the aircraft.

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

The scanner rotation rate and the wavelength/frequency.

The size of the water droplets 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.

26. In the MAPPING MODE the airborne weather radar utilises a

Pencil beam effective from zero to 150 NM.

Pencil beam to a maximum range of 60 NM.

Fan shaped beam effective up to a maximum of 50 NM to 60 NM range.

Fan shaped beam effective up to a range of 15 NM.

27. 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?

6000 ft above the level.

At the same level.

18000 ft above the level.

12000 ft above the level.

28. 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 in.

20 cm.

56 cm.

87.5 cm

29. 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.

Areas of wind sheer and severe aircraft icing.

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

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

Detect areas of possible severe turbulence in cloud.

Give an indication of cloud tops.

Extend the mapping range.

Inhibit unwanted ground returns.

31. What frequency is typical chosen for AWR systems?

93.75 GHz. (93 decimal 75 kHz).

93.375 GHz. (9 decimal 375 GHz).

93.75 MHz. (93 decimal 5 kHz).

9375 kHz.

32. On an AWR the sequence of colours indicating increasing water droplet size is?

Black, amber, red.

Blue, green, red.

Green, Yellow, red.

Blue, amber, red.

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

Pulse repetition frequency.

Pulse length.

Beam width.

Carrier wave frequency.

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

Of aurora borealis (polar light) causing false returns.

Of getting a distorted because of the ice reflections.

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

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

35. 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 and move to the top of the screen

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

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

The automatic gain control of the AWR is activated.

The brightness of the display.

The receiver sensitivity in order to achieve optimum target acquisition.

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

37. Before commencing a flight the weather radar should?

Not be switched on until clear of buildings.

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

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

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

38. 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.

52.5 cm.

52.5 in.

20 cm.

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

Secondary radar in the VHF band.

Secondary radar in the SHF band.

Primary radar in the SHF band.

Primary radar in the UHF band.

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

The radar beam is pencil shaped.

Maximum tilt on the aerial will often be used.

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

The radar beam is a cosecant beam.

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

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

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

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

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

42. 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.

As a zero point for range measurement.

To determine the aeroplane's height above the surface.

To determine that the weather radar is functioning.

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

Iso-echo areas, which are, coloured black.

Large areas of flashing red colour.

Blank iso-echo areas where there is no colour.

Colour zones being closest together.

44. 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 down tilt.

0 degrees tilt.

2.5 degrees up tilt.

5 degrees down tilt.

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

To display echoes from other aircraft.

To display different intensity of precipitation.

To display ground height differences.

To display clouds, indicating different levels of visibility.

46. Which of the following list of phenomena are least likely to be detect by airborne weather radar?

Clear air turbulence.

Precipiation.

Wet snow and turbulence in cloud that has precipitation.

Turbulence in cloud that has precipitation.

47. The heaviest turbulence is likely t be encountered?

In the area of heaviest precipitation.

Where the area of heaviest precipitation is closest to the edge of the thunderstorm cell.

About half way between two thunderstorm cells.

In the very core of a thunderstorm cell.

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

Show a clearly defined hole.

Coloured magenta.

Show a rapid gradient of change from magenta to yellow.

Coloured red.

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

Wake turbulence.

Areas of possible turbulence is cloud.

Turbulence in cloud.

CAT

50. AWR contour mode is used for?

Shorts range mapping.

Identifying areas of maximum turbulence within a cloud.

Identifying rain bearing clouds.

Long range mapping.

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