Vayudoot Aviation

1. MLS consists of?

An azimuth transmitter and an elevation transmitter operating on a separate frequency and a DME.

A common azimuth and elevation transmitter.

An azimuth transmitter and an elevation transmitter operating on a shared frequency and a DME.

Overlapping centre-line lobe transmission in azimuth angled to provide glide slope information.

2. In which frequency band does the Microwave Landing System (MLS) operate?

SHF.

UHF.

VHF.

EHF.

3. The frequency band of MLS is?

VHF.

UHF.

SHF.

VLF.

4. Which one the following correctly lists the major ground based components of a Microwave Landing System(MLS)?

Separate azimuth and elevation transmitters, DME facility.

Combined azimuth and elevation transmitters, DME facility.

Combined azimuth and elevation transmitters,outer and inner marker beacon.

Separate azimuth and elevation transmitters, outer and middle marker beacons.

5. Distance on MLS is measured by?

Phase comparison between the azimuth and elevation beams.

Measurement of the time taken for the secondary radar pulse to travel from the MLS transmitter to the aircraft receiver.

Co-located DME.

Measurement of the time taken for the primary radar pulse to travel from the MLS transmitter to the aircraft receiver.

6. The addition of DME-P to MLS is necessary to?

Allow linear approaches.

Assure a constant angular velocity of the azimuth and elevation sweeps.

Obtain three dimensional positions.

Support the time referenced scanning beam.

7. The MLS uses a technique based on?

Pulse modulation.

frequency modulated duplex.

Magnetic referenced scanning beam system.

Time referenced scanning beams.

8. MLS can minimise multi path errors because?

MLS has a large beam width than ILS.

The transmissions can be interrupted to avoid reflection by stationary objects.

The frequency of MLS is much higher than the frequency of ILS.

The transmision reverts to circular polarisation when the beam is reflected by stationary objects.

9. The coverage of MLS is _________ either side of the centreline to a distance of _______?

40 degrees, 20 nm,

20 degrees, 40 nm,

20 degrees, 20 nm,

40 degrees, 40 nm,

10. MLS can minimise multi-path errors because?

MLS has a large beam width than ILS.

The frequency of MLS is much higher than the frequency of ILS.

The transmission reverts to circular polariasation when the beam is reflected by a stationary object.

The transmission can be interrupted to avoid reflection from stationary objects.

11. In an MLS the azimuth information is available in the approach sector?

To a distance of 10 NM in an 80 degrees wide sector.

To a distance of 20 NM in a 110 degrees sector.

To a distance of 10 NM in a 110 degrees sector.

To a distance of 20 NM in an 80 degrees wide sector.

12. MLS frequencies and available channels are?

In the SHF band for the MLS elements and the VHF band for the DME, 100 channels available.

In the range 5060 to 5090 MHz, 200 kHz spacing, giving 150 available channels.

In the SHF band, 300 kHz frequency separation, giving 200 channels available.

In the VHF and UHF band, 40 channels available.

13. Which one of the following methods in used by a Microwave Landing System (MLS) to indicate distance from the runway threshold?

Timing the interval between the reception of sequential secondary radar pulses from the MLS station to the aircraft.

A DME co-located with the MLS transmitters.

Timing the interval between the transmission and reception of primary radar pulses from the aircraft to MLS station.

Measurement of the frequency shift between the MLS azimuth and elevation transmissions.

14. Compared to the ILS, MLS has the following advantages?

Many different approaches to the same runway may be defined by 1 set of ground equipment.

All approaches to all airfield will use the same channel, which means that the aircraft equipment will be a single channel receiver.

No special receivers are required in the aircraft.

Aircraft separation will automatically be arranged by the ground equipment.

15. MLS not equipped with DME-P?

Provides basically the same approach capabilities as ILS.

Provides the capability for segmented approaches but not for curved approaches.

Provides the capability for curved approaches but not for segmented approaches.

Provides the capability for CAT 3 approaches.

16. The azimuth transmitter of a Microwave Landing System (MLS) provides a fan-shaped horizontal approach zone which is usually

+ or - 30° of the runway centre-line.

+ or - 40° of the runway centre-line.

+ or - 60° of the runway centre-line.

+ or - 50° of the runway centre-line.

17. MLS is primarily being installed in airports where?

Meteorological conditions are likely to cause ILS ducting by super refraction.

Topographical conditions preclude the installation of ILS marker beacons.

ILS encounters difficulties because of surrounding buildings and/or terrain or interference from local music station.

The main approach paths lead over water.

18. Which one of the following is an advantage of a Microwave Landing System (MLS) compared with an Instrument Landing System (ILS)?

There is not restriction on the number of ground installations that can be operated because there is an unlimited number of frequency channels available.

It does not require a separate azimuth (localiser ) and elevation (azimuth) transmitter.

The installation does not require to have a separate method (market beacons or DME) to determine range.

It is insensitive to geographical site and can be installed at sites where it is not possible to use an ILS.

19. The MLS utilises a?

Phase referenced scanning beam system.

Magnetic referenced scanning beam system.

Frequency referenced scanning beam system.

Time referenced scanning beam system.

20. Making an MLS approach, the aircraft?

Receives elevation information 3 times as frequently as the azimuth information.

Receives elevation information 13 times per second.

Receives elevation information 2 times per second.

Receives elevation information 39 times as frequently as the azimuth information

21. The principle of operation of MLS is?

Phase comparison directional beams.

Frequency comparison of reference beams.

Lobe comparison scanning beams.

Time referenced scanning beams.

22. Microwave Landing Systems (MLS) use guidance signals formed from?

Intersecting modulated signals transmitted on very narrow beams.

Time referenced scanning beams.

Phase difference between an amplitude modulated reference signal and a frequency modulated variable signal.

Radar beams.

23. Which of the following is an advantage of MLS?

Can be used in inhospitable terrain.

Has a selective access capability.

Uses the same aircraft equipment as ILS.

Is not affected by heavy precipitation.

24. The MLS frequencies and available channels are?

In the VHF and UHF bands, 50 available channels.

In the SHF band, 300 kHz frequency separation giving 200 available channels.

In the range 5060 to 5090 MHz, 200 kHz separation giving 150 available channels.

In the SHF band for MLS elements and the VHF band for the DME, 100 available channels.

25. In an MLS system, the azimuth coverage is?

+/- 10 degrees.

+/- 40 degrees.

+/- 8 degrees.

+/- 35 degrees.

26. MLS installations notified for operation, unless otherwise stated, provide azimuth coverage of

+ or - 40° about the nominal courseline out to a range of 30 NM.

+ or - 20° about the nominal courseline out to a range of 20 NM.

+ or - 20° about the nominal courseline out to a range of 10 NM.

+ or - 40° about the nominal courseline out to a range of 20 NM.

27. In a MLS, the time that elapses between the passage of the TO scan and the FRO scan at the aircraft position is?

Directly proportional to the angular position f the aircraft.

None of the above.

Indirectly proportional to the angular position of the aircraft.

Not related to the angular position of the aircraft.

28. MLS not equipped with DME?

Provides the capability for CAT3 approaches.

Provides the capability for curved approaches but not segmented approaches.

Provides the capability for segmented approaches but not curved approaches.

Provides basically the same approach capabilities as ILS.

29. A microwave landing system operates?

On one of 400 channels in the band 5.30 to 5.09 GHz.

On one of 400 channels in the band 5030 GHz to 5090 GHz.

On one of 200 channels in the band 5.30 to 5.90 GHz.

On one of 200 channels in the band 5030 to 5090 GHz.

30. The addition of DME-P MLS is necessary to?

Support the time referenced scanning beams.

Allow linear approaches.

Obtain three dimensional positions.

Assure a constant angular velocity of the azimuth and elevation sweep.

31. Which one of the following is an advantage of a Microwave landing System (MLS) compared with an Instrument Landing System (ILS)?

It is insensitive to geographical site conditions and can be installed in sites where it is not possible to use an ILS.

It does not require a separate azimuth (localiser) and elevation (glideslope) transmitter.

The installation does not require a separate method (marker beacons or DME) to determine range.

There is not restriction on the number of ground installations that can be operated because there is an unlimited number of channels availbale.

32. The scanning beam of the MLS system is called?

Magnetic referenced scanning beam system (MRSB).

Time referenced scanning beam system (TRSB).

Frequency referenced scanning beam system (FRSB).

Phase referenced scanning beam system (PRSB).

33. Which answer correctly completes the following statement? The characteristics of an MLS station are that it uses

An elevation transmitter at the approach end of the runway, an azimuth transmitter at the upwind end of the runway, and a single frequencies.

One transmitter for both azimuth and elevation and a single frequency.

One transmitter for both azimuth and elevation and two frequencies.

An azimuth transmitter at the approach end of the runway, an elevation transmitter at the upwind end of the runway, and two frequencies.

34. A MLS without DME-P provides?

A staged approach but not with a curved path.

An approach with a curbed path but not staged.

An ILS-like approach.

A category 3 approach.

35. MLS is primarily being installed at airport where?

ILS encounters difficulties because of surrounding buildings and/or terrain or interference from local music stations.

Meteorological conditions are likely to cause ILS ducting by super refraction.

The main approach paths lead over water.

Topographical conditions preclude the installation of ILS marker beacongs.

36. Which of the following statements is true in respect to the Microwave Landing System (MLS)?

Azimuth and elevation signals are transmitted on the same UHF frequency.

Azimuth and elevation signals use the same aerial on a time sharing basis.

A special precision DME, operating in the SHF band, provides range information.

Range information is provided by precision DME operating in the UHF band.

37. Microwave Landing Systems allow the aircraft to fix its position accurately in three dimensions by means of?

Timing of the passage of two scanning beams integrated with DME.

Information from four satellites transmitting microwaves.

Timing of the interval between pulses in azimuth and elevation and timing the delay for pulses to reach the aircraft to define range.

Directional aerials and DME.

Question Bank

Questions for MLS