Communication and Navigation Systems Flashcards
What kind of antenna is used for the ATC transponder?
A UHF stub antenna
What is the preferred location for the ATC transponder antenna?
On the center line of the belly of the aircraft as far from any other antenna as practical
What are the three basic types of antenna used in aviation?
- Dipole Antenna
- Marconi Antenna
- Loop Antenna
What type of antenna are most aircraft VHF communication antennas?
Marconi antennas
How do static wicks aid the aircraft communication radios?
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
On what two frequencies does the emergency locator transmitter operate?
121.5 and 243.0 megahertz
Where is the ELT transmitter normally located on an aircraft
In the tail of the aircraft or as far aft as possible, so it will be least likely to be damaged in a crash
How often should ELT batteries be replaced or recharged?
By the date marked on the outside of the transmitter
How often must ELTs be inspected for proper installation, battery corrosion, operation of the controls and sensor, and the presence of the radiated signal?
Every 12 calendar months
What causes an ELT to actuate?
An inertia switch that detects an impact parallel to the longitudinal axis of the aircraft as would occur in a crash
How is an ELT tested to determine that it is working?
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
What are the basic components of a radio communications system?
- Microphone
- Transmitter
- Transmitting and receiving antennas
- Receiver
- Speakers or headphones
What frequency range is used by most modern voice communication systems?
The VHF (Very High Frequency) band (118.0 to 136.975 MHz)
What does the term “ADF” stand for?
Airborne Direction Finding
What is the function of VOR equipment?
Navigation
Name the components of a typical airborne VOR navigation system
- Receiver
- Antennas
- Frequency selector
- Visual display indicator
What does DME stand for?
Distance Measuring Equipment
At what intervals must an ATC transponder system be certified?
Every 24 calendar months
Why are two antennas usually required for an ILS system?
The localizer and glideslope signals are transmitted on different frequencies
What information does the glideslope beam provide?
Vertical guidance to enable the aircraft to maintain the correct decent angle
What is the power source for an ELT?
An internal battery
Describe one method of monitoring the signal output during an ELT test
Tune a communications receiver to 121.5 MHz
How would you determine if the batteries in an ELT are due for recharge or replacement?
By looking for an expiration date for recharge or replacement on the battery and/or in the aircraft maintenance records
At what times is a test of an installed ELT permitted?
During the first 5 minutes after the hour and for no more than 3 sweeps
Where on the aircraft would you expect to find a DME antenna?
Generally on the bottom of the fuselage in a location that isn’t blocked by the wing during turns
Describe the shape and location of a transponder antenna
Either a short blade or a short wire with a ball end located on the bottom of the fuselage
