Communication and Navigation Systems

Question 1

What kind of antenna is used for the ATC transponder?

Answer 1

A UHF stub antenna

Question 2

What is the preferred location for the ATC transponder antenna?

Answer 2

On the center line of the belly of the aircraft as far from any other antenna as practical

Question 3

What are the three basic types of antenna used in aviation?

Answer 3

1. Dipole Antenna
2. Marconi Antenna
3. Loop Antenna

Question 4

What type of antenna are most aircraft VHF communication antennas?

Answer 4

Marconi antennas

Question 5

How do static wicks aid the aircraft communication radios?

Answer 5

Static wicks aid in the dissipation of static that builds up on the aircraft. Built-up static can cause radio receiver interference caused by corona discharge emitted from the aircraft as a result of precipitation static

Question 6

On what two frequencies does the emergency locator transmitter operate?

Answer 6

121.5 and 243.0 megahertz

Question 7

Where is the ELT transmitter normally located on an aircraft

Answer 7

In the tail of the aircraft or as far aft as possible, so it will be least likely to be damaged in a crash

Question 8

How often should ELT batteries be replaced or recharged?

Answer 8

By the date marked on the outside of the transmitter

Question 9

How often must ELTs be inspected for proper installation, battery corrosion, operation of the controls and sensor, and the presence of the radiated signal?

Answer 9

Every 12 calendar months

Question 10

What causes an ELT to actuate?

Answer 10

An inertia switch that detects an impact parallel to the longitudinal axis of the aircraft as would occur in a crash

Question 11

How is an ELT tested to determine that it is working?

Answer 11

Actuate the test switch and listen on 121.5 or 243.0 MHz. Make the test during the first five minutes of the hour and do not allow the ELT to operate for more than 3 sweeps

Question 12

What are the basic components of a radio communications system?

Answer 12

1. Microphone
2. Transmitter
3. Transmitting and receiving antennas
4. Receiver
5. Speakers or headphones

Question 13

What frequency range is used by most modern voice communication systems?

Answer 13

The VHF (Very High Frequency) band (118.0 to 136.975 MHz)

Question 14

What does the term “ADF” stand for?

Answer 14

Airborne Direction Finding

Question 15

What is the function of VOR equipment?

Answer 15

Navigation

Question 16

Name the components of a typical airborne VOR navigation system

Answer 16

1. Receiver
2. Antennas
3. Frequency selector
4. Visual display indicator

Question 17

What does DME stand for?

Answer 17

Distance Measuring Equipment

Question 18

At what intervals must an ATC transponder system be certified?

Answer 18

Every 24 calendar months

Question 19

Why are two antennas usually required for an ILS system?

Answer 19

The localizer and glideslope signals are transmitted on different frequencies

Question 20

What information does the glideslope beam provide?

Answer 20

Vertical guidance to enable the aircraft to maintain the correct decent angle

Question 21

What is the power source for an ELT?

Answer 21

An internal battery

Question 22

Describe one method of monitoring the signal output during an ELT test

Answer 22

Tune a communications receiver to 121.5 MHz

Question 23

How would you determine if the batteries in an ELT are due for recharge or replacement?

Answer 23

By looking for an expiration date for recharge or replacement on the battery and/or in the aircraft maintenance records

Question 24

At what times is a test of an installed ELT permitted?

Answer 24

During the first 5 minutes after the hour and for no more than 3 sweeps

Question 25

Where on the aircraft would you expect to find a DME antenna?

Answer 25

Generally on the bottom of the fuselage in a location that isn’t blocked by the wing during turns

Question 26

Describe the shape and location of a transponder antenna

Answer 26

Either a short blade or a short wire with a ball end located on the bottom of the fuselage