Communications Flashcards
VFR Frequency Range
118.000 to 137.000 MHz (exclusive of 137.000)
Current VHF frequency spacing
Previous VHF frequency spacing
# channels
New: 8.33kHz
Old: 25kHz
# channels: 2280 up from 760
Rounding VHF frequencies to channels
Round to final figure of 0 or 5
Pronunciation of decimal frequencies
If frequency ends ###.#00 only pronounce first DP
Otherwise pronounce all DP
(e.g. one two three decimal four, or one two three decimal four five zero)
Max distance at which to contact ATSU
- International airport
- Other aerodrome
- Safteycom
International airport - 25nm
Other aerodrome - 10nm
Safetycom - 10nm
Max height at which to contact ATSU
- International airport
- Other aerodrome
- Safteycom
International airport - 10,000ft
Other aerodrome - 3,000ft max (ideally 1,000ft)
Safetycom - 2,000ft
[All aal]
Emergency Frequency
121.5
2 types of VHF-NAV equipment
VOR - VHF omnidirectional range
ILS - Instrument Landing System
2 types of NAV equipment excl VHF NAV
DME - Distance Measuring Equipment
ADF - Automatic Direction Finder
Radio frequency range used by NAV equipment
108-118MHz
How do transponders work
Detects signal from SSR (Secondary Surveillance Radar) and reflects back boosted signal with additional info
TCAS
- Stands for
- Description
Traffic Collision Avoidance System
Uses Mode S transponder data to give traffic avoidance instructions to pilots
DAP
- Stands for
- Description
Downloaded Aircraft Parameters
An additional set of aircraft data sent by mode S transponders such as heading, airspeed, vertical rate, ground speed, true track angle etc.
TIS
- Stands for
- Description
Traffic Information System
Information gathered from nearby mode S transponders sent back to a mode S transponder unit and displayed to pilot for collision avoidance help
TIS
- How it works
- Aircraft range
A TIS equipped SSR will send information to a mode S transponder about the closest aircraft within 6nm and 3,500ft.
Information is displayed on a unit to the pilot and colour coded
TIS
- Limitations
- Only closest 8 aircraft displayed
- No avoidance action given, for information only
- Only available on approach radar stations (i.e. near large airfields), not enroute
- Must be within 50nm to receive info
How does TCAS work?
TCAS reads transponder signals from nearby aircraft and gives collision avoidance guidance to the pilot.
Frequency Monitoring Code
This is a squawk code you use to indicate that you are monitoring a particular radio frequency in a given chart area
CAVOK
- Short for
- Definition
Ceiling and Visibility ok
- Visibility > 10km
- No cloud below 5,000ft aal or below minimum sector altitude & no cumulonimbus clouds
- no precipitation reaching ground, thunderstorms, shallow fog or low drifting snow
Relationship between UTC, Zulu time and GMT
They are all the same time
Which numbers are never abbreviated (e.g. hundreds, thousands)?
- Time
- Altimeter settings
- Transponder codes
- Runway #
- Headings
- Callsign digits
- Radio frequencies
- Wind direction/speed
3 types of radio message from ATSU
Clearance - Only issued by ATC, must be followed and read back in full
Instruction - Should be followed if safe to do so. Ideally read back.
Information - Don’t read back (e.g. wind)
Readability ratings
Strength:
5 - perfect
1 - unreadable
5 key aerodrome and circuit r/t positions
1) Parked - Departure info, taxi.
2) Holding - ATC route clearance, ready for departure
3) Downwind
4) Final - Cleared to land/land @ your discretion
5) Runway vacated
Booking out vs flight plan
Booking out is not the same as making a flight plan. Booking out is not required if a flight plan has been filed.
Callsign types (4)
i) Reg
ii) Manufacturer name or category & reg
iii) Telephony designation & Reg
iv) Telephony & flight ID
Callsign abbreviations
Reg can be abbreviated to first digit and at least the last 2 digits.
Telephony designation and flight ID can’t be abbreviated
Declaring yourself as student
Put before registration in first message.
Once acknowledged by controller (when they say student back) you can drop it.
Roger
“I have received all of your last transmission”
Wilco
“I understand your last message and will comply”
ATIS
Air Terminal Information Service
What to state to ATSU when you have ATIS info
ATIS reference letter (e.g. information Charlie) and pressure setting
2 scenarios for radio initiation
En-route - Request a service
Arrive/depart - Request clearance/information
Freecall info
ADDPAA
A) Aircraft Callsign + type
D) Departure point
D) Destination
P) Position
A) Altitude
A) Additional details/intention
Freecall info
CARPAI
C) Callsign
A) Aircraft type
R) Route
P) Position
A) Altitude
I) Intentions
Radio message priority list
1) Distress
2) Urgency
3) Direction-finding
4) Flight safety (e.g. ATC messages)
5) Meteorological
6) Flight regulatory messages (e.g. scheduling, maintenace)
FIS
- Stands for
- Staff
(Aerodrome) Flight Information Service
Staffed by Flight Information Service Officers (FISOs).
Services a FISO can provide
- Basic service
- Alerting service
Status of FISO
FISOs are licensed and regulated by CAA, but not as stringent as ATC controllers
Who can a FISO control?
Aircraft on the ground only
Status of A/G radio operator
Not licensed but have passed a CAA competency exam
Safety com frequency
135.475
Services provided by ATC
- Air traffic control service
- Basic service
- Alerting service
ATC unit names
Main ones are Tower, Approach, Ground.
Also others such as Radar, Director
Initial contact arriving into ATC ATZ
Contact approach, if not tower, 10nm away.
Initial contact arriving into MATZ
Contact 15nm or 5min (greater) before reaching zone boundary
MATZ ATC requirement consideration
MATZ itself doesn’t have strict rules, but they do contain an ATZ around the aerodrome which has the same rules around following ATC as any other ATZ
MATZ radio terminology
“Roller” - touch and go
“Go around” - another circuit
“(number) in” - number of aircraft in the circuit
“Dead side” - call made joining circuit
Military circuit pattern
Rounded crosswind and base legs.
“Final” call made when abeam start of runway when a continuous semi-circle turn is made into the runway
Switching to ATIS messages
“Request temporary frequency change…”
“Back on frequency”
VOLMET
Voice weather broadcast that covers an area with several aerodromes
ATIS typical update frequency
Every 30 mins, usually 20 past and 50 past
Trend codes for weather
- NOSIG
- TEMPO
- BECOMING
NOSIG - no significant changes expected in 2 hours from observation time
TEMPO - conditions expected to be temporary, up to 60 mins between stated times
BECOMING - indicates the forecast change will become permanent
Contaminated runway conditions (8)
- Standing water
- Compacted snow
- Dry snow
- Wet snow
- Ice
- Wet ice
- Frost
- Slush
General runway conditions (4)
- Dry
- Wet
- Slippery Wet
- Contaminated
Runway condition codes
0 to 6, 0 is worst, 6 is best
VFR request to cross controlled airspace
“Request zone transit”
ACC
- Stands for
- Services (4)
Area Control Centre
- ATC in controlled airspace
- Air Traffic Advisory Service to aircraft flying on advisory routes
- Flight Information Service (FIS)
- Alerting Service
LARS availability
Within 30nm of radar centre, up to FL100
LARS services
- Deconfliction service (VFR flights shouldn’t request unless sure you will stay in VFR conditions)
- Traffic service
Position report format
A: Aircraft callsign
P: Position
T: Time
L: Level
N: Next position & ETA
RMZ & TMZ
- Stands for
Radio Mandatory Zone
Transponder Mandatory Zone
RMZ & TMZ on charts
RMZ - Blue half-moons facing in
TMZ - Magenta half-moons facing in
TMZ entry requirements
Need altitude capable transponder but can contact ATS to obtain approval to enter without.
Don’t need approval to enter if you have transponder (unless it’s also controlled airspace) but recommended to make contact.
RMZ entry requirements
Must not enter until controlling authority has accepted your message (i.e. “pass your message”). If they ask you to standby you can’t enter.
Contact them in plenty of time.
Services available from FISO
Basic service only
Basic Service
- Who is it available to (flight, airspace class)
VFR: Class G and E
IFR: Class G (but might not be appropriate for IMC)
Basic Service
- Traffic info provided?
- Changing heading/FL
Traffic information may or may not be passed, do not expect it.
You can change heading or flight level without informing ATSU.
Procedural Service
- Who is it available to?
Available to IFR only
Procedural Service
- Traffic info provided?
- Changing heading/FL
Traffic info on basic service with same ATSU provided, but no deconfliction with them
Must follow agreed instructions of ATSU.
Deconfliction Service
- Who is it available to?
Available to IFR only in class F and G (i.e. LARS unit)
Do not request if you aren’t qualified for IMC and flight will take you outside VMC.
Deconfliction minima
5nm and 3,000 ft for unidentified craft
3nm and 1,000 ft for identified craft under same controller
Traffic Service
- Who is it available to?
VFR: Class G and E
IFR: Class G
Traffic Service
- Instructions and changing heading/altitude
Pilots may choose own heading/altitude or may be allocated by ATSU.
If an instruction is accepted you must follow it and unless safety would be compromised don’t change without approval from controller.
SRA
- Stands for
- Description
Surveillance Radar Approach
Radar enabled approach guidance from controller down to point where you are visual with runway.
SRA
- Pressure setting
Should set QFE, however it is possible to use QNH and controller will adjust instructions accordingly.
Reporting points chart depiction
Reporting points sometimes marked on specified routes.
Filled in triangle is mandatory reporting point, outlined triangle is on-request reporting point.
Services related to danger areas
Difference
- DACS - Danger Area Crossing Service
- DAAIS - Danger Area Activity Information Service
DAAIS can’t provide crossing clearance but can advise if the area is active
VDF
VHF Direction Finding
VDF requests
QDM - Magnetic heading to the station
QDR - Magnetic bearing from the station
QTE - True bearing from the station
[QUJ - True to the station]
Radio request for QTE
“True bearing”
Response if ATSU says “Transmit for DF”
ATSU requesting period of radio transmission to enable them to locate you using VDF
“Transmit for DF - golf alpha bravo charlie delta”
Class of VDF result
Class A: +/- 2 degrees
Class B: +/- 5 degrees
Class C: +/- 10 degrees
Class D: worse than class C
Contact before penetrating MATZ
Technically don’t require clearance but recommended.
Should contact 15nm or 5 mins flying before boundary and listen on ATC frequency.
Must comply with instructions from ATC of the ATZ.
CTR
- Stands for
- Description
- Class
Control Zone
>5n radius zone around large aerodromes, ground to stated FL
Class D
CTA
- Stands for
- Description
- Class
Control Area
Area between flight levels
Class A, C or D
TCA/TMA
- Stands for
- Description
- Class
Terminal control/manoeuvring area
Confluence of several busy airports
Class A, C, D or E
Airway
- Description
- Class
Corridor 5nm either side of a straight line
Class A, C or E (only C or E where passing through TMA, CTA or CTR of that status)
UK Class C airspace
Only class C airspace in the UK is above FL195
Special VFR
- Rules
- Comply with ATC clearances
- Remain clear of cloud
- Fly within limitations of license
- Comply with low flying regulations
- Avoid entering ATZ without permission
Action if SVFR instruction would breach low flying regs
Reject instruction, you are responsible for complying with regulations
Rules around radio failure under SVFR
- If outside CAS with or without clearance, you can’t enter
- If inside CAS and transiting, must exit via nearest route
- If inside CAS with clearance inbound to field can continue, land ASAP and look for signals from tower
Crossing an airway (2)
VFR - Cross at right angles beneath airway
IR qualified pilots in VMC - File a flight plan (before or when airborne) and request crossing clearance 10 mins before arrival
Emergency
- Radio frequency & transponder code to use
If already in contact with ATSU contact them first. If no response switch to 121.5.
If you have a specific transponder code (not 7000), keep it. Otherwise select 7700.
Distress & Diversion unit (121.5) services
SAR
Emergency services
Position fixing services
Mayday call content
a) Mayday - Mayday - Mayday
b) Station addressed
c) Reg
d) Type
e) Nature of emergency
f) Intentions
g) Position
h) FL/altitude
i) Heading
j) Qualifications
k) Any other info (eg POB)
Simulating unsure of position
“Training fix - Training fix - Training fix”
Simulating emergency
“Practice pan - practice pan - practice pan”
Station addressed
Reg
- Once accepted with “pass your message”, pass the full practice pan call
Relaying mayday
Start with “Mayday Mayday Mayday”, station, reg then:
“Have intercepted mayday from xxxx … “
Communicating radio failure
Squawk 7600 or
Fly 2 minute leg triangles - RH if receiver is working, LH if total failure.
If transmitter working but receiver isn’t, say “transmitting blind”
Entering controlled space with radio failure
Don’t enter without clearance
If you have clearance can enter the space, unless SVFR in which case stay outside
Speechless code
1 - Yes
2 - No
3 - Say again
4 - Request homing
1 long - Manoeuvre complete
2 long - Aircraft developed another emergency
Speed of radio waves and transmission through vacuum
Travel at speed of light and can travel through a vacuum
Speed of light
300,000km per second
Types of wave - radio & speech
Radio - electromagnetic waves
Sound - pressure waves
Frequency range of human hearing and human speech
Hearing: 20Hz to 20kHz
Speech: 100Hz to 10kHz
Full range of VHF
30Mhz to 300Mhz
How is a radio signal transmitted
Carrier wave is modulated (amplitude modification or frequency modification) by a speech wave to create a single wave that can be transmitted.
Receiver de-modulates the transmitted wave to recover the speech wave.
Typical range of VHF transmissions
60nm @ 2,000ft aal
120nm @ 10,000ft aal
Amplitude
Height of wave above centre line - not peak to trough
Range limitations - tower, approach
Tower - 4,000ft, 25nm
Approach - 10,000ft, 25nm
Range calculation for VHF
VHF range in nm = sqrt(1.5 x altitude in feet)
Benefit of HF
HF range is significantly larger
HF frequencies in use
Which have longer range?
5-8MHz in daytime, 3MHz ok at night.
Interaction between HF and ionosphere
Skip zone
HF waves partially reflect off ionosphere increasing range but also causing out of phase interference.
Creates a skip zone between where ground waves reach and where sky waves reflect to.
Higher frequencies reflect further away, bigger skip zone.
Impact of ionosphere on different frequencies and day/night
VHF continues through ionosphere so no impact.
Low frequency (<5MHz) HF signals are absorbed in the day so range is reduced, but can work well at night.
Higher freq HF signals work well all the time.
LF/MF completely absorbed in day but strong sky waves at night.
Why HF frequencies at day/night?
Use 5-8 MHz in day as sky waves still produced.
At night 3MHz works well as attenuation decreases and sky waves will be stronger.
In general may have to pick a wave to have the right range given skip zone.
Use of LF & MF
Used for NDBs (200kHz to 420kHz)
Use of UHF
Used by ILS, DME and SSR
VLF
Used by some navigation systems
Instruction from ATC to go around
“Go around, I say again, go around, acknowledge”
Light signals on ground
Red: stop
Flash red: Move clear of landing area
Green: Cleared to take off
Flash green: Cleared to taxi
Flash white: Return to starting point
Light signals in air
Red: Do not land
Flash red: Do not land, aerodrome closed
Green: Cleared to land
Flash green: Return to aerodrome and await permission to land
Flash white: Land at aerodrome after steady green
What does “QSY en route” mean?
Change to your next radio frequency
How to tell somebody to slow down speech
“Speak slower”
What does “Hx” mean?
Aerodrome no specific open hours
Aeronautical mobile service
A mobile service between aeronautical stations and aircraft stations or between aircraft stations
SEC-URI-TAY message
Safety broadcast by military ground station
Visibility reporting accuracies
In metres up to 5km
In km from 5km to 10km
>10km “One Zero Kilometres or more”
When can “land after” instructions not be given?
At night
Term for message to “all stations”
Broadcast
Radio reply to being told to squawk a number
Just repeat the number
Distance of “long final” call
8 to 4 miles to runway threshold
Radio for 360 turn
TREE-SIXTY TURN
Terminology for an action for the purpose of delaying/spacing
“For spacing”
How many times to send blind message
Repeat the message twice within a single transmission
How to read QNH 1000
QNH WUN TOUSAND
Request to climb to and maintain flight level 50
Climb FL50
Recommended speech rate
100 wpm
