OGRAD 07.03 – Airborne Weather Radar – LMS

Results

Q1. Which of the following cloud types is most readily detected by airborne weather radar when using the ‘weather beam’?

altostratus

stratus

cumulus

cirrocumulus

cumulus

Q2. Airborne weather radar systems use a wavelength of approximately 3 cm in order to:

detect the larger water droplets

obtain optimum use of the Cosecant squared beam

detect the smaller cloud formations as well as large

transmit at a higher pulse repetition frequency for extended range

detect the larger water droplets

Q3. Airborne weather radar uses a particularly high frequency radar signal, at 9 – 12 GHz, in order to

Get the most accurate range and bearing information

All 3 answers are correct

Making it possible to present a colour display of the weather situation

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

Q4. The stabilisation of the weather radar, aerial is effective

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

For up to +/- 45° of combined roll and pitch

For up to +/- 5° roll and pitch

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

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

Q5. Which of the following is a complete list of airborne weather radar antenna stabilisation axes?

roll, pitch and yaw

roll and pitch

pitch and yaw

roll and yaw

roll and pitch

Q6. On the airborne weather radar display, different colours are used

High ground

Echoes from other aircraft

To display different intensity of precipitation

Clouds, indicating different levels of visibility

To display different intensity of precipitation

Q7. In Airborne Weather Radar (AWR), the main factors which determine whether a cloud will be detected are:

size of the water drops; diameter of radar scanner

rotational speed of radar scanner; range from cloud

size of the water drops; wavelength/frequency used

range from cloud; wavelength/frequency used

size of the water drops; wavelength/frequency used

Q8. In which mode of operation does the aircraft weather radar use a cosecant radiation pattern.

WEATHER

MAPPING

MANUAL

CONTOUR

MAPPING

Q9. A frequency of 10 GHz is considered to be the optimum for use in an airborne weather radar system because:

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

less power output is required in the mapping mode

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

static interference is minimised

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

Q10. The advantage of the use of slotted antennas in modern radar technology is to:

virtually eliminate lateral lobes and as a consequence concentrate more energy in the main beam

have a wide beam and as a consequence better target detection

simultaneously transmit weather and mapping beams

eliminate the need for azimuth slaving

virtually eliminate lateral lobes and as a consequence concentrate more energy in the main beam

Q11. A weather radar, set to the 100 NM scale, shows a squall at 50NM. By changing the scale to 50 NM, the return on the radar screen should:

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

increase in area and move to the top of the screen

Q12. Which of the following lists phenomena that CANNOT be detected by weather radar?

clear air turbulence; turbulence in cloud with precipitation

dry hail; clear air turbulence

snow; turbulence in clouds with precipitation

snow; clear air turbulence

Q13. When the airborne weather radar is operating in it’s primary mode, to detect precipitation,

Maximum tilt of the aerial will often be used

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

The radar beam is pencil-shaped

The radar beam is a cosec-beam

The radar beam is pencil-shaped

Q14. In general the operation of airborne weather radar equipment on the ground is:

unrestrictedly permitted in aerodrome maintenance areas

permitted anywhere

totally prohibited

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

Q15. When switching on the weather radar, after start-up, a single very bright line appears on the screen. This means that the:

transmitter is faulty

scanning of the cathode ray tube is faulty

receiver is faulty

scanner is not rotating

scanning of the cathode ray tube is faulty

Q16. You want to use your airborne weather radar to detect areas with turbulence. Consider the following statements:

If you are flying at low altitude, the detection of turbulence at levels below the aircraft may difficult because of ground returns

All 3 answers are correct

You should select the cosec beam and carefully adjust the aerial tilt

Using the cosec beam, the height of top of clouds, with possible turbulence, may be calculated using the 1: 60 rule.

If you are flying at low altitude, the detection of turbulence at levels below the aircraft may difficult because of ground returns

Q17. The ISO-ECHO facility of an airborne weather radar is provided in order to:

inhibit unwanted ground returns

detect areas of possible severe turbulence in cloud

give an indication of cloud tops

extend the mapping range

detect areas of possible severe turbulence in cloud

Q18. 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 orange to red

green to yellow to red

yellow to amber to blue

green to red to black

green to yellow to red

Q19. A frequency of airborne weather radar is :

93.75 MHz

9375 MHz

9375 GHz

9375 kHz

9375 MHz

Q20. In the MAPPING MODE the airborne weather radar utilises a:

fan shaped beam effective up to a range of 150 NM

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

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

Q21. The pencil shaped beam of an airborne weather radar is used in preference to the mapping mode for the determination of ground features:

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

when approaching coast-lines in polar regions

beyond 100 NM because insufficient antenna tilt angle is available with the mapping mode

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

Q22. Using the airborne weather radar, before take-off

The contrast control should be adjusted to maximum contrast

The antenna tilt control should be set to max negative tilt

The gain control should be adjusted according to the light conditions expected when airborne

The radar transmitter should not be operated when personnel is observed in the sector ahead of the aircraft

Q23. In order to ascertain whether a cloud return on an Aircraft Weather Radar (AWR) is at or above the height of the aircaft, the tilt control should be set to: (Assume a beam width of 5°)

2.5° down

2.5° up

0°

5° up