11.5.2 - Avionic Systems Flashcards
What does the VHF communication system provide?
Allows radio comms over distances of up to 200nm
What does the HF system provide?
Uses earth’s ionosphere to reflect radio communication systems
ACARS
Aircraft Communication, Adressing and Reporting System. exchange of flight and maintenance data
What does all communication require? (2)
Information (audio, video, digital) and a carrier (transport the info.)
Radio frequency bands (8)
Radio frequency bands
VLF = up to 30Khz - military RF LF = 30 kHz to 300 kHz - public radio MF = 300 kHz - 3 MHz - public radio HF = 3mhz - 30 MHz - Long distance comms VHF = 30mhz - 300mhz - comms up to 200nm UHF = 300mhz - 3ghz - military radar SHF = 3ghz - 30 ghz - satcom, weather and altimeter EHF = 30hg - 300ghz - not used in comms and navigation
What do microphones transform?
Acoustic info into electrical signals
What do loudspeakers transform?
Electrical signals back into acoustic info
Purpose of static wicks?
Discharge static build up, which could cause damage to electrical systems.
What is the ACP and it’s main components?
Audio Control panel.
3 VHF transceiver selectors
2 HF transceiver selectors
Cabin, flight, PA and SATCOM knob
What are the 3 positions for the filter selector knob?
V - Voice, voice information only
R - Range, indent code only
B - Both, both
Priority of PA amplifiers (5)
- Cockpit
- Purser
- Cabin crew
- Prerecorded announcements
- Boarding music
Types of CVR - Cockpit voice recorder
Analogue - stores the last 30 mins and erases the previous automatically
Digital solid state - stores the last 120 minutes, previous is overwritten
When does the CVR operate?
Starts on engine start up, and finishes when last engine shutdown on ground
What is the CVR erase switch?
Allows the crew to maintain privacy when parking brake is applied on the ground
VHF system components (3)
System 1 is for the CAPTAIN’S voice comms
System 2 is for the FIRST OFFICER
System 3 is for the ACARS system
Each system has its own antenna located on the fuselage.
What can indicate a system failure?
A missing side tone.
What is the RMP and its function?
Radio Maintenace Panel - used to select the required frequency for VHF and HF systems.
Why is Satcom advantageous over HF?
HF is affected by solar activity, satcom is not.
HF components (3)
Antenna, antenna coupler and transceiver.
What is satellite signals to earth, and vice versa, known as?
Downlink and uplink, respectively.
Two types of ACARS reporting systems?
Automatic (engine, eta, out, in) and manual (ATC, Load sheet, report)
What does satcom provide?
SATCOM provides reliable worldwide digital data transfer for ACARS, cockpit voice and telex communications and passengers voice, telex and fax communications.
SATCOM components (3)
Aircraft earth station ( AES)
Ground earth station (GES)
Satellites, obvs
3 types of Emergency locator transmitter (ELT)
Fixed, portable and fixed/portable.
What can activate an ELT?
A fixed ELT can be activated by 5G or more force in the longitudinal axis and a portable one can be activated upon contact with water.
3 components of the radio navigation system
ADF
VOR
ILS
Radio Nav - What is the ADF system?
The automatic directional finder uses radio signals from ground stations to calculate the direction to the station, which is indicated in the cockpit.
Radio Nav - What is the VOR system ?
The VHF omnidirectional range system uses radio signals from VOR ground stations to calculate the direction to the station. The information is used by the autopilot.
Radio Nav - what is the ILS system ?
The Instrument Landing system uses ground signals to determine position from the runway using a localiser, glide slope and marker beacons.
What are the two types of navigation chart
ICAO and enroute
What are VFR and IFR?
Visual flight rules and Instrument flight rules.
What are the two types of North?
True North (TN) - Is the direction to the geographical North Pole.
• Magnetic North (MN) - Is where the magnetic field lines are gathering
What is Track? (TK)
The movement of flight over the earth in relation to Heading.
What is ‘drift’ in relation to heading and track?
The angle at which the track deviates from the heading, usually due to wind.
What is Bearing?
The direction of an aircraft to the position of an object, in degrees.
What is the frequency band for ADF?
190Khz - 1750 KHz.
What is the principle behind the VOR system?
The lighthouse principle.
- The flashes in all directions occur when the rotating light beam passes through magnetic north.
- Measure the time between the all directions flash light and seeing the rotating beam, enable the direction of the lighthouse to be worked out.
ILS - how does the Localizer work?
Splits the runway into halves (lobes) of different frequency.
Left side is 90 KHz.
Right side is 150 kHz.
Deviation from the centreline is shown as a deflection pointer in cockpit.
ILS - How does the Glide slope work?
The same as the Localizer, but with upper and lower lobes.
Upper lobe is 90khz.
Lower lobe is 150khz.
Deviation is shown in the cockpit as a deviation pointer.
ILS Autopilot poor weather landing categories (3)
CAT 1 - 800m of runway visiablity at 200ft
CAT 2 - 400m of runway visibility at 100ft
CAT 3 - 200m of runway visibility below 100ft