Comms and Nav Q's Flashcards
What is the purpose of the VHF system?
For short range communications
What is the frequency range of VHF communications?
118 - 136.975 Mhz AM
Whats is the channel spacing of VHF?
25Mhz - 760 Channels or 8.33 Mhz 2280 Channels
In VHF is it possible to communicate in duplex mode?
No
How do you change RX to TX in VHF?
By selecting the PTT button
How is the operation frequency tuned?
Tunes using the knobs on the VHF control panel
The VWSR shows more than 2.0 what does this mean?
There is a problem with the antenna tuning circuit.
What is the purpose of the HF system?
Long distance voice communications between aircraft and ground.
What is the frequency range of HF communications?
2-29.999 Mhz AM
The HF system will work in what modulation modes?
AM and SSB ( Upper side band)
What is the channel spacing in the HF system?
1Khz / 28000 Channels
What is the task of the antenna coupler and where is it located?
It is matched to the transmission frequency to tune to the minimum standing wave ratio
In receive mode is it necessary to tune the antenna circuit?
Yes
How is the antenna tuning mode indicated to the pilots?
The TIP or tune in progress indication will appear
What is the purpose of the SELCAL system?
It provides aural and visual indications of the calls received from ground stations quipped with a coding device.
What communications systems are used for SELCAL?
VHF and HF
What is the function of a SELCAL decoder?
It will compare the code activated on the code select panel to the code being received.
How is a SELCAL call indicated in the flight deck?
A buzzer and the call legend flashes amber.
Where is the SELCAL code selected?
The SELCAL code is selected on the code selection panel, there a re 4 code select wheels using 17 binary wires.
What is the purpose of the SATCOM system?
Long range communication using the Satellite network, Ground earth station and Aircraft earth station.
How is a call processed between and aircraft and the office?
Aircraft transmits to the satellite and the satellite transmits this back to the GES where it travels through a network to the airline computer
How many satellites are used by IMMERSAT?
4 satellites and ten ground stations
In SATCOM which unit has control over the whole system?
The satellite data unit (SDU)
The SATCOM uses position and attitude signals why?
Because the beam from the antenna must be pointed directly at the satellite.
Does SATCOM operate in simplex or duplex mode?
The RFU ensures the system works in complete duplex mode.
What is the Uplink/Downlink frequency between AES and satellite?
1.5/1.6 Ghz
What is the Uplink/Downlink frequency between GES and satellite?
4-6 Ghz
What is the purpose of the ACARS system?
The ACARS system is used to TX or RX automatically generated reports to or from a ground station.
Which aircraft communication system will broadcast ACARS messages?
VHF or SATCOM
What are the 4 ACARS providers?
SITA, Arinc, Air Canada and AVICOM
What is the ACARS frequency in Zurich?
131.725 Mhz
OOOI Stands for?
Out, Off-, On- and In Event
What are the two technologies used for Audio Integrating?
Analogue and Digital
What does switching the voice/ident switch do?
Voice - Only voice will be heard
Ident - voice and full identification will be heard
What does the filter inside a ACP do?
It cancels the morse code 1020Hz and is made up of dependant elements like coils and capacitors
Which function is now digitally controlled in a digital ACP?
Volume is now controlled with the use of potentiometers
What is the function of the RAD/INT switch located on the ACP or side stick?
RAD - Connects Boom/Mask to the radio
INT - Connects Boom/Mask to the flight interphone system
The flight interphone is used to communicate between?
Between the flight deck themselves and flight deck and ground crew when starting engines
The cabin interphone is used to communicate between?
Between the cabin and the flight deck
The service or maintenance interphone is used for communication between?
maintenance personal during maintenance activities
What is the main component in each interphone system?
Amplifier
To communicate from inside the cabin the attendant has to use?
Cabin Handsets
How is the ground engineer called from the cockpit to communicate?
A horn in the nose wheel bay
Is it possible to communicate between the different interphone systems?
Yes and there are switches to do so
What is the purpose of the CVR
To determine the cause of an aircraft accident by recording on an endless tape for a minimum of 30 mins.
What is the CVRs recording capacity?
At least 30 mins on 4 channels
On a CVR channels 1-4 what are their sources?
1 - Captins Audio
2 - FO Audio
3 - Observers
4 - Cockpit Area
What is the recording media of a CVR?
endless magnetic tape or Solid state memory.
When is the CVR powered?
When one of the engines is started (fuel levers open) on manually through the CVR/FDR gnd cont pushbutton switch.
When can the CVR data be erased?
When the aircraft is on the ground and the parking brake is set.
The ULB is provided to?
Generate a pulse when immersed in water
What kind of signal does the ULB send out and for how long?
A 37.5Khz acoustic signal and operates continually for 30 days.
When must the internal battery of a ULB be replaced?
2-6 years
What is the purpose of an ELT?
A self contained radio transmitter with an inertia switch inside that operates at around 5G.
What signals does an ELT transmit?
121.5 Mhz in the VHF band and 243.0 Mhz in the UHF band
How long with the ELT transmit for?
48 hours
How is the ELT powered?
By an internal battery pack
what is the new third frequency added to the ELT operation?
406Mhz
What are the components in a HF system?
HF transceiver, Antenna, Antenna coupler, HF Mode control panel, MIC, Headphones
The ADF system shows a direction towards a?
Non Directional Beacon
Name the 2 antennas that are used in ADF?
Omnidirectional sense antenna and 2 Loop Antennas
How many Nulls are there when a loop antenna is rotated in a radio field?
2 Nulls
What is the frequency range for ADF?
190 - 1750 Khz
What is the indicator in the flight deck that shows ADF direction?
Radio Magnetic Indicator
What is the heading or reference line known as?
Lubber Line
What is the name of the ADF direction?
QDM or Direction Magnetic
What is relative bearing?
Angle from the aircraft heading to the pointer
What is absolute bearing?
Absolute bearing is with respect to north going clockwise.
What 2 functions does VHF Navigation comprise of?
VOR and ILS
What is TCAS I?
Provides proximity warning codes, to assist the pilot in visual acquisition of intruder aircraft. Intended for use by smaller and general aviation aircraft.
What is TCAS II?
Provides traffic advisories and resolution advisories in a vertical direction to avoid conflicting traffic. AC and larger commuters will use this
What is TCAS III?
Still under development, will provide traffic advisory and resolution in the horizontal as well as vertical directions.
What does the TCAS computer communicate with on an intruder aircraft?
Transponder
What can a TCAS computer calculate from an aircrafts transponder?
Its bearing, range and closure rate and its relative altitude (ATC mode C or S)
TCAS transmits on ………… and receives on 1090 Mhz?
1030 and 1090Mhz
Describe the TCAS antenna?
Low profile, 4 element directional devices capable of TX in 4 stable directions and receiving Omni baring information.
What does a TA (traffic advisory) provide?
Assists the pilot to make a visual search. An arrow in the indicator shows if the aircraft is climbing or descending.
What does a RA (Resolution Advisory) provide.
It shows the pilot the vertical speed or corrective action to prevent a collision.
Below 500 feet rad alt all RA in TCAS are?
Supressed.
How is a Resolution Advisory indicated?
Red and Green segments which can illuminate instead of normal vertical speed indication.
What information does the GPS receiver receive?
3D position, velocity and time information.
