11.5.2 Avionic Systems Flashcards
What sections can communications be divided in to
Aircraft communications
Radio
Accident communication
How far will VHF allow communication
200 nautical miles
What is the purpose of SATCOM
Allows worldwide communication via satellite
What is the Very Low Frequency (VLF) and Very High Frequency (VHF)
VLF - up to 30 KHz
VHF - 30KHz to 300GHz
What different types of loudspeaker is there in the cockpit
- Hand held
- Integrated microphone
- Area microphone
What is the purpose of the audio switching in the cockpit
If the captains or first officers malfunctions it can be switched to a 3rd crew member
What is the flight inter phone used for
Communication between flight deck and crew
Where can ground crew connect to speak to the flight deck through an inter phone on the ground
The nose wheel
What system does a PA system work off in the aircraft
A priority system using high and low priority chimes to gain attention
How long does the analogue flight recorder record before the end of a flight
The last 30 mins
What components are inside a flight recorder
Area microphone
Underwater location beacon
Recorder
Control panel
The construction of a CRV is steel. How many g loads can it withstand
1000g loads
How many audio inputs does a CRV have
4 inputs
At what point will a voice recorder begin recording in an aircraft
As soon as the first engine is started
Shuts down 5 mins after engine shut down
What is the frequency used for the international emergency frequency
121.5MHz
What is the gap usually between two frequency channels
25KHz
760 frequencies available
In Europe more high flight levels are needed, what channel spacing is used
8.3KHz
More than 2000 channels
VHF systems have 3 systems. What is each for
System 1 - Captains voice
System 2 - First officer
System 3 - ACARS, can be used instead of others if system fails too
Where are the 3 VHF antennas on aircraft usually
No.1 and no.2 are on top of fuselage
No.3 on the bottom
What is the radio management panel used for
Selecting the VHF and HF radio
The radio management panel has two functions what are these
Left window - Active window, shows the operating frequency of the selected frequency
Right window - Standby window, shows the new selected window
If VHF system no.3 is selected what will be displayed
ACARS or DATA as no manual frequency needs to be selected for ACARS
What does a HF system consist of
Transceiver
Antenna
An antenna coupler - tunes antenna to correct frequency
What does a HF transmitter permit
Amplitude modulation
Transmission output power in the region of 200w-400w
Frequency range from 2MHz to 25MHz in steps 1 or 0.1KHz
On an RMP what does the SQL (squelch) knob control
Level of noise suppression
ACARS data transfer from air to ground is called what
Downlink
Ground to air is uplink
What type of automatic reports are ACARS able to produce
OUT OFF ENGINE REPORTS ON IN
What manual ACARS messages can be sent to ATC
Load sheet report Call request ATC request Report request Maintenance report Crew &
What 3 components does SATCOM consist of
Satellite
Aircraft earth station
Ground earth station
How long will an emergency locator transmitter last for
48 hour battery life
What types of emergency location transmitters are there
Fixed - Permanently on fuselage
Portable/fixed - Used on smaller aircraft
Portable - (buoyant) can be removed from life raft
What two radio navigation systems are there
Automatic direction finder ADF (Oldest system)
VHF omnidirectional range VOR (most common system)
What is ILS (Instrument Landing System) used for
Automatic landing in poor conditions
What are the 3 subsystems for ILS
Localiser
Glide slope
Marker beacon
What two types of chart can be used for aircrew navigation
ICAO charts
Enroute charts - Most commonly used on commercial flights
Which ICAO chart is used for small private aircraft
VFR - Good flight conditions with visual references
IFR - Bad weather no visual references (Commercial aircraft)
What is the difference between magnetic north and true magnetic north called
Variation (VAR)
Can be east or west
The direction of where the aircraft is pointing (heading) is measured what of true north
Clockwise
What is relative bearing
The direction of the aircraft to an object
Reference must be the longitudinal direction of the aircraft
What 3 ways can aircraft navigation tune
Manual
Automatic - via the FMS
Automatic - via nav control panel or radio management panel
What is an ADF
Automatic Direction Finder, radio navigational system that receives radio signals in the frequency band 190 - 1750KHz to the ground
In terms of ADF what are non Directional beacons used for
Enroute navigation
On an ADF system what is the loop antenna for
Used for approach
Usually located with ILS locator beacons
On an ADF system what is the sense antenna responsible for
Receives the electric part of the wave and sends the sense signal to ADF receiver
What is the purpose of an ADF receiver
Use both loop and sense signals to create relative bearing
What 2 signals do VHF omnidirectional range (VOR) ground stations use
Reference signal - transmitted in all directions when the variable signal passes magnetic north
Variable signal
What is an advantage and a disadvantage to Doppler VOR ground stations over conventional VOR
Advantage - Better performance in areas where there’s a better chance of signal reflection. Mountains
Disadvantage - more expensive
What is ATIS
Automatic Terminal Information Services
VOR spoken audio at large airports transmit weather and traffic reports
What is the localiser responsible for on an ILS system
Transmit 90-150Hz signals for lateral guidance which create two Directional lobes
What two Directional lobes does the ILS localiser create
Left - 90 Hz
Right - 150 Hz
What does 1 dot on the ILS indicator signify
1 degree offset to the localiser
What two lobes will a glide slope transmit on a decent path
Upper - 90 Hz
Lower - 150 Hz
On the glide slope, the upper and lower lobe are equal to the centre line with a slope of what
2.5 - 3 degrees
Where are the glide slope antennas and localiser usually located on an aircraft
Under the nose, radome
Why would some aircraft use the VOR antenna as the localiser
They share the same frequency range
What does 1 dot usually equal on a glide slope deviation
0.35 degrees - 200ft
What are the poor weather landing categories
CAT 1 - 800m of the runway visible at 200ft
CAT 2 - 400m of the runway at 100ft
CAT 3 - 200m of the runway below 100ft
What is the appearance of a marker beacon
Cannot sharper antenna along the bottom centreline of the fuselage
At what height will a radio altimeter begin to work
2500ft
What frequency and output does the transceiver work off a radio altimeter
Between 4200 and 4400 MHz frequency with a power output of 100mw
What is the ground proximity warning system for
Warn the crew when the aircraft becomes mistakingly too close to the ground
What 3 methods will the ground prox warning system work by
Aural alert
Annunciator alert
Alert messages
What advanced system will show the grounds terrain the the nav display
Enhanced Ground Proximity Warning System (EGPWS)
What alert is shown when the aircraft comes into land with the wrong gear and flaps situation
Terrain clearance mode
“Too low gear”
(“Too low flaps”)
How does the Terrain Awareness (TA) show terrain
Green, yellow and red dots
What are pop up functions
Automatic Situation which happen when a situation becomes critical
‘Wind shear’
Terrain warning
When will the TA (Terrain Awareness) system give a caution before the occurrence
When 60’seconds away
When will the TA give a warning alert before entering terrain
30’seconds away
What type of test level is Level 1 GPWS test
Go or NO Go
How many levels of test is a GPWS rated on
6
How does Distance Measurement Equipment (DME) operate
Uses the aircraft slant distance to the ground station and altitude combined create actual distance
What does an interrogator do in a DME system
Located in row avionics bay, generates signal for transmission and makes distance calculation
What system is identical to the DME antenna
ATC antenna, work off the same frequency
How does the weather radar system work
Pulses a 180 degree sweep ahead of the aircraft and will reflect objects such as water droplets
Where must a weather radar not be operated
On the ground as it creates the same effect as a microwave oven
What 3 codes should never be selected on the ground on the ATC control panel as they are emergency codes
7500 - hijacking
7600 - radio fail
7700 - if aircraft is in emergency
What is the purpose of TCAS (Traffic Collision Avoidance System)
Protect airspace around TCAS aeroplanes
How many aircraft does TCAS monitor
50
What is the TAU area
The closest point of approach to the TCAS aeroplane
What will happen if the aircraft reaches TA - TAU
“Traffic Traffic” alert
RA - TAU climb
What will appear on the TCAS monitor when another aircraft is climbing or descending at a rate of more than 500ft/min
Arrow up/ arrow down
What is a hollow diamond indication on TCAS monitor
Other traffic
What is a solid diamond on the TCAS monitor on the ND
Proximate traffic
What is a solid circle on the TCAS monitor
Traffic alert
What is a solid square on the TCAS monitor
Resolution advisory
What does GPS stand for
Global Positioning System
How does GPS accurately gather an aircrafts position
Uses 4 GPS satellites
How long does it take a GPS satellite to orbit earth
12 hours
What GPS service is used by the military
Precise Positioning Service (PPS)
Standard Positioning Service is civilian aircraft
What is the accuracy of Standard Positioning Service GPS and how can it be improved
15m
Differential GPS
How does a differential GPS improve location accuracy
Reference station at airport calculates the positional error and the difference in the accurate location
By how far does differential GPS improve precision
By 3m
What is the purpose of FANS (Future Air Navigation System)
Used space based navigation and satellite to enhance communication from aircraft to ATC
Future Air Navigation Systems will improve the situational awareness of ATC, why
Automatic transmission of flight data important for surveillance
Automatic Dependant Surveillance (ADS)
What is a combination of heading and attitude referencing systems called
Inertial Stabilised System (ISS)
What two types of gyro are there
2 gyros with 3 degrees of freedom
3 gyros with 2 degrees of freedom
What is the most commonly used Gyro
Laser gyro
In a laser gyro, what 2 things are proportional
Travel time and rotational speed
What are the motions along the axis of the aircraft measured with
Accelerometer
Electrolyte, mass/spring, pendulum
What is the preferred type of accelerometer
Pendulum
What is the gimble platform in a Inertial Stabilised System
Always parallel to earth independent to the aircraft altitude
What will the IRU require on the ground
A 10 minutes align phase
