Navigation Instruments

Question 1

What is the main electronic nav aid in use today?

Answer 1

VOR

Question 2

What frequency does the VOR operate on?

Answer 2

108-117.96MHz

Question 3

Two signals are transmitted for a 360 degree signal with a phase difference.

Answer 3

T

Question 4

When are the two signals “in phase”

Answer 4

360

Question 5

What are the signals called that VORs transmit?

Answer 5

Radials

Question 6

Each dot in the VOR receiver is how many degrees?

Answer 6

2 degrees

Question 7

What does a VOR receiver do if no signal is being received?

Answer 7

A flag is displayed

Question 8

What are the advantages for VOR?

4 things

Answer 8

• not effected by weather
• Accurate radials
• two VORS can provide a fix
• Accurate instrument approaches

Question 9

What are the disadvantages of VOR?

Answer 9

Range limited line of site

Question 10

What is a TACAN?

Answer 10

Military version of VOR/DME

Question 11

What is the frequency band of TACAN?

Answer 11

960-1215MHz

Question 12

What are the hurts of the two components of TACAN?

Answer 12

15Hz

135Hz

Question 13

What are TACANs co-located with?

Answer 13

VOR

Question 14

What are TACAN/VOR known as?

Answer 14

VORTAC

Question 15

If the antenna of a TACAN fails what signal can’t be used?

Answer 15

Azimuth

Question 16

In the VORTAC which part performs the function of a DME?

Answer 16

The TACAN.

No need for a separate, co-located DME

Question 17

Because the rotation of the antenna creates a large portion of the azimuth signal, if the antenna fails, the azimuth component is no longer available and the TACAN downgrades to?

Answer 17

A DME only Mode

Question 18

How does the DME operate?

Answer 18

By transmitting and receiving paired pulses from the Ground station

Question 19

The transmitter in the aircraft sends out very narrow pulses at a frequency of about?

Answer 19

1,000MHz

Question 20

What frequency does DME operate in?

Answer 20

UHF wave band

Question 21

How accurate is DME?

Answer 21

1 nm

Question 22

What error does DME suffer from?

Answer 22

Slant error.

15nm DME can no longer be used

Question 23

Why are DMEs in two frequencies for interrogator and transponder?

Answer 23

To avoid a/c interrogating each other

Question 24

How does a DME work?

Answer 24

• Interrogator transmits
• Transponder replies
• computer works out range from elapsed time between signals
• Indicator shows range on digital or linear display

Question 25

The antenna used for transmission and reception is a?

Answer 25

Small shark fin mounted on the underside of the aircraft.

Question 26

Modern DME receivers incorporate digital readout of frequency, Distance from DME station and can automatically calculate the aircraft’s groundspeed. True or False?

Answer 26

True

Question 27

A DME displays?

Answer 27

Slant range in nautical miles

Question 28

What are the advantages of DME?

Answer 28

- VOR/DME installation can be used to make an IAP - Simple to use/ calculate groundspeed - Obtain a fix from 2 DMEs

Question 29

What are the disadvantages of the DME ?

Answer 29

Only gives slant range Not accurate at high altitudes over DME station

Question 30

What is ILS?

Answer 30

A precision runway approach that provides accurate guidance in both azimuth and elevation.

Question 31

Why does the ILS consist of?

Answer 31

A localiser Transmitter Glidepath Transmitter Marker beacons or NDB Approach lighting system

Question 32

Where is the localiser situated?

Answer 32

Upwind of the runway 300m for the threshold.

Question 33

Where is the glidepath situated?

Answer 33

300m for the landing threshold and offset 100-200m form the centre line.

Question 34

How far are the Outer marker Middle marker Inner Marker

Answer 34

3-6nm 900-1200m 300-450m

Question 35

What frequency does the localiser transmit on?

Answer 35

VHF 108.1-111.95MHz

Question 36

What is the range of coverage for a localiser?

Answer 36

35 degrees either side up to 17nm and 10 degrees either side up to 25nm

Question 37

What frequency does the Glide path operate on?

Answer 37

UHF 329.3-335MHz

Question 38

What is the coverage of the Glide path?

Answer 38

Horizontally 8 degrees either side of the centre line for 10nm and below 0.45xGP and 1.75xGP above.

Question 39

List the different ILS categories

Answer 39

-Cat 1 - Lower than standard Cat 1 -CAT2 -Other than standard CAT2 - CAT3: A B C

Question 40

What are are the minimum heights/ visibility for CAT 1?

Answer 40

DH 200ft Vis not less than 800m RVR not less than 550m

Question 41

What are are the minimum heights/ visibility for lower than standard CAT 1?

Answer 41

DH 200ft RVR 400m

Question 42

What are are the minimum heights/ visibility for CAT 2?

Answer 42

DH 200-100ft RVR 350m

Question 43

What are are the minimum heights/ visibility for other than CAT 2?

Answer 43

DH 200-100ft RVR 350m Used if some/ all Precision approach lights are out.

Question 44

What are are the minimum heights/ visibility for CAT 3A?

Answer 44

DH 100ft RVR 200m

Question 45

What are are the minimum heights/ visibility for CAT 3B?

Answer 45

DH 50ft RVR 200-75m

Question 46

What are are the minimum heights/ visibility for CAT 3C?

Answer 46

No limitations

Question 47

What does the localiser do?

Answer 47

Provides lateral guidance

Question 48

What does the glidepath do?

Answer 48

Provides vertical guidance to the pilot during landing

Question 49

What are the advantages of ILS?

Answer 49

1) Pilot interpreted and easy to use 2) Precision approaches possible 3) can be couples to auto-pilot for automatic approach and landings

Question 50

What are the disadvantages of ILS?

Answer 50

Subject to interference from local VHF stations Reflections from other ground facilities can cause false glide paths Shortage of frequencies

Question 51

What does MLS stand for?

Answer 51

Microwave Landing System

Question 52

How does MLS work?

Answer 52

Uses passive arrays to send scanning beams towards aircraft. Aircraft uses a receiver to calculate its position by measuring the arrival time s of beams. Provides azimuth, elevation, and distance as well as back azimuth, from missed approach

Question 53

What is the MLS coverage?

Answer 53

60 degrees either side of centre line to 14 nm 40 degrees either side of centre line to 20nm

Question 54

What is the max vertical | Coverage of MLS?

Answer 54

30 degrees maximum limit 15 degrees