Communication Systems Flashcards
What are the main components of a communication system
- VHF radio
- UHF radio
- HF radio
- Controller (UFCP)
- Intercom (ICS)
- Transponder (including ADS-B)
- ELT (emergency locator transmitter)
What are the 3 main frequencies and their bands
HF = 3 - 30 MHz VHF = 30 - 300MHz UHF = 300 - 3000MHz
What are HF comms primarily used for and what is their range. And can it be used beyond line of sight?
Long range comms
1600km
Yes
What are average VHF comms distance at 1000ft and 10,000
30, 123 miles
What are the 3 main components of a typical VHF system
Transceiver
Controller
Antenna
What is the typical operating band of a UHF system
225 - 400 MHz
Is UHF AM or FM used by military?
Am
What are some functions a cockpit intercom provides
- Voice comms between aircrew
- Monitoring communications reciever audio
- Monitoring navigation reciever audio
- Selection of a comms system to transmit on
- Audio control to transmitting comms system
What has the implementation of digital data allowed in modern aircraft
Allows multiple systems to communicate with eachother through a single interface
(UFCP)
What generally activates an emergency locator transmitter (ELT)
Ejection or excessive G
What is an ELT
Emergency battery powered transmitter
What does the PC21 communication system provide audio comms between and what is its secondary function
- both pilots
- pilot and ground crew
- own aircraft and other aircraft
- own aircraft and interrogators (ground or air)
2nd:
- Emergency transmission for aircraft location
What components does the comms system consisit of in the avionics bay
- Audio managment unit (AMU)
- UHF/VHF recievers
- ELT
Where are the respective antennas for the comms system
- Upper ATC/ ADS-B
- UHF/ VHF 2
- ELT
All just forward of Vertical stabilizer - UHF/ VHF 1
Below others, on underside - Lower ATC/ ADS-B
Below wings
What does the UHF/VHF reciever guard do
Constantly monitors VHF & UHF guard frequencies 121.5 & 243 MHz
What 2 main components make of the ELT
Transmitter uni
Interface unit
What does the pc21 have to dissipate static charge and how many
Static discharges
21
How does static charge affect communications
It can disrupt LF reception or VHF interference
What are the 5 communication controls in the front cockpit
- COMM panel on right console
- Decouple panel above RH mfd
- ELT remote control panel on rear of right console
- PTT switch PCL
- Instructor switch on left console
Where is communication system related data shown
- UFCP
- FMS
- MFDs (both)
What does the COMM 2 button on the decouple panel do
Allows instruction to transmit without student hearing
What does the AMU control
UHF, VHF radios
Intercom
Aural warning tones
Where does the AMU recieve inputs from
DWP
RIOCs 3 & 4
What would cause damage to AMU WRT receiving and transmitting
If simultaneously transmitting and receiving occured on the same channel
COMM 2 is identified as? and where is its antenna?
Transceiver 2
Forward of vertical stabilizer
What are both transceivers controlled by
UFCP & FMS
What are the selecatble frequencies on the UFCP
30 - 400 MHz
Whats the transmitton range when using 400MHz band
100nm
What powers each transciever, AMU & ATC/ ADS-B Transponder
COMM 1 = BATT BUS
COMM 2 = GEN 1 BUS
AMU = BATT BUS & GEN 1 BUS
Transponder = BATT BUS
What happens when you press on the centre of the PTT switch on the plc
Mutes all incoming comms and radio nav audio signals to both pilots earphones
Does pressing down on the ptt switch affect aural tones and volume
No
What happens if the ptt switch is operated continuously for 45 seconds and why
Amu stops transition. In event of switch failure or of stuck in transmit position
Can both pilots transmit simultaneously, if yes how
Yes
Only on seperate radios
Where is the alternate ptt switch
Comm panel
What else is on the comms panel
Event button
Amu channel selector
How do you control comms volume
Rotary switch on ufcp
With the MC powered and operating, the ATC transponder is controlled through what
UFCP
What are the characteristics of transponder standby mode
Doesnt reply to interrogations
Doesnt broadcast any info
Will remain in standby after TO if not changed
The transponder ON mode initiates ADS-B operation which has 3 modes, what are they
OFF
MIL (DEAFULT)
IFR
If the MC fails, is switched off or UFCP fails, what controls the ATC transponder
FMS
The ELT control switch has 3 positions, what are they. What position should the switch be on during normal operations
On
Armed
Test/ reset
Armed
What are the consequences of a UFCP failure
- COMM 1 & COMM 2 cant be controles through UFCP
- Loss of volume adjustment
What systems are lost when MC fails
- MFDs
- UFCPs
What components are still functional
FMS
COMM PANEL
PPT switch on pcl
How are radios controlled in the event of a MC failure
FMS
What happens when amu 1 fails?
Amber AMU 1 FAIL on MFD
Attn gtr
Aural tone
What failures would cause comms from front and rear cockpit and intercom to stop working completely . What would be associated warnings/ messages
Amu 1 - 3 fail
Amber on mfd
Aural
Attn gtr
What indicates that the ELT is in transmit mode
Amber ELT ACTIVE on mfd
Attn gtrs
Aural tone
Test flash on ELT panel
