The document discusses air traffic control and navigation principles, outlining flight rules such as VFR and IFR, and the technologies used for navigation in commercial aviation. It explains the role of air traffic control (ATC) in regulating air traffic and ensuring safety within designated airspace, alongside the various systems and methods such as GPS, INS, and radio beacons that facilitate navigation. The document also covers the organization of airspace, flight planning, and emergency communication protocols in aviation.

1. Air Traffic
Control & Air
Navigation
Stourbridge Amateur Radio Club
(11 February 2013)
Presented by Kelvin Lam

2. For download:
• http://www.slideshare.net/goodnight033
/air-traffic-control-air-navigation

3. We ensure your safety…

4. Air Navigation

5. Aims:
• Basic terminology for aviation
• Different types of air navigational rule
• How these navigation technologies are
implemented in commercial aviation
industry

6. 2 Flight Rules
• There are two main flight
conditions:
• VFR (Visual Flight
Rule)
The pilot operates an
aircraft when the visibility
is high, and can fly a
plane with the reference
of the ground and local
landmarks/landscape,
and able to avoid other
air traffic.

7. • IFR (Instrumental
Flight Rule)
The pilot rely only on
the airborne
instruments. Navigation
is based on electronic
signals. The exterior
visual reference is not
safe (due to
weather/nighttime/altitu
de etc.)

8. Navigation
• We probably would
have used these
devices before:
SatNav (GPS)
Map reading
Asking for direction

9. • But up at 30,000 ft up the sky, you cannot ask
a friend how to get to New York, nor you
cannot simply read a map and say: “I saw the
Atlantic Ocean, I must be heading to New
York”!

10. Basic concepts
• Directions:
They are measured in magnetic north
bearings (000 to 360).
• Altitudes:
In most part of the world they are measured
in Imperial “feets”. Often the term “flight level”
is used to represent altitudes.
In the Eastern Bloc often metric “metres” is
used instead for political and historical
reasons.

11. Basic concepts
• Speed/Velocity:
 In Western countries
speed in aviation is
measured in knots
(kts).
 In the Eastern Bloc
(some), speed is
measured in km h-1
(kph).

12. Basic concepts
• Taxiway
• Runway
• Ramp/Jetway/Parking
• Threshold line
• Touch-down zone
• Displaced threshold/runway safety zone

13. Basic concepts
• There are different type of speed:
GS (Ground Speed)
The speed of the aircraft relative to the
ground.
IAS (Indicated airspeed)
The speed of the aircraft relative to the still air
of a certain air pressure. (2992 Hg)
TAS (True Air Speed)
The speed of the aircraft relative to the air
outside.
Wind speed
The rate of the wind. TAS-WS = IAS.

14. Flight deck

15. True North and Magnetic North
• Angular difference +/- 3 degrees.

16. Why Air Navigation is important?
• Busy airspace (you can cause accidents if
you fly in the fly route and altitude)
• Flying into countries with no transition
rights (Korean Air 007)
• Saves fuel when flying in the correct
weather and route
• Saves time!
• You are flying to the correct destination

17. How should the map look like?

18. Or this?

19. Map projection
• The first is known as Mercator-map
projection method. Such
conventional map is easy to read,
however assumed the world is a
perfect sphere.
• (The latter is known as the
Robinson projection method).
• After satellite launches, human
realised the world is a sphere.
• Charts nowadays use a WGS84
standard to ensure it is accurate and
valid. It is based on GPS with an
accuracy of +/- 2m.

20. Great Bear
• Aviators in the past
used the Polar Star to
locate the north point.
• But imagine the air
navigator has to
constantly plot where
they are using the stars
and the airspeed: this is
not accurate!
• This is known as
astronavigation.

22. Modern navigation
• Air charts
• ATC (Air Traffic
Controls)
• GPS (Global
Positioning
System)
• INS (Inertial
Navigation System)
• Radio beacons
• Etc…

23. Air charts
• They are basically the aviator’s version of
the “Explorers Map”.
• It shows the …
Routings (jetways)
Beacons (VOR, DME transmitter)
Aerodromes (airfields, airport)
Frequency of the ATC

25. Air Traffic Controls
• They give directions to pilots to regulate
traffic in the airspace.
• They also provide navigation service by
giving bearings or information about
airspace traffic/nearest airport.

26. Global Positioning System
• It was developed by the
Department of Defense of
America. It was allowed for
civilian use at the 1980s.
• It is composed of a system
with 24 satellites. A GPS
receiver needs signals
from 3 satellite so that,
using the mean of
triangulation, to figure out
the exact position/co-
ordinate in the map.

27. Global Positioning System
• The satellite each has a very
accurate atomic clock. The
time at the satellite should
be (around) 2 seconds faster
than the UTC due to
Einstein’s relativity theory.
• Time delay/difference
measures the distance that
the wave has travelled.
• GPS signals include satellite
information and euphemistic
details (positioning).
• Signals are sent at
1.8MBit/second.

28. Inertial Navigation System
• Inertia: In other words, momentum. It is
the relunctance of an object/particle to
change its velocity.
• INS is a method of navigation
relying solely on inertial
equipment: accelerometer &
gyroscope.
• The aircraft is calibrated in a
certain position. The “map is
plotted” in that exact position.
The plotter moves as the IN
equipment sense a change in
inertia (i.e. acceleration,
airspeed, altitude change) thus
finds out the position of the
aircraft.

30. Radio Beacons
• There are a few
types of beacons:
NDB (Non-
directional beacon)
(or VOR, VHF
Omnidirectional
Range)
Single letter HF
ILS Localiser
(Marker beacon)

31. VOR (Conventional Navigation)
• The VOR beacon sends
out a 3 letter Morse code
of the station name.
• The pilot sets a omni-
bearing (CRS bearing),
which is the bearing
which the plane should
aim for.
• If the bearing from the
radio wave mismatch to
that of the CRS bearing,
the pilot must be off-
course.

32. VOR
• VOR radio has a channel frequency
between 108.00 to 117.95MHz.
• The accuracy of VOR navigation is +/- 1.4
degree.

33. DME
• Distance – measuring
equipment:
• By calculating the time-
delay between the time
which the incident wave
is sent, and the time
which the responded
wave is received
• We work out the slant
distance between the
aircraft and the beacon.

34. Performance-based navigation
(PBN)
• Instead of drifting away from a
specific route, sometimes aircraft
fly at a specified 3D airspace
between two waypoints.
• Such navigation required on-board
alerting and monitoring.
• A route of RNP1 allows the aircraft
only to drift away from specific
route by 1 nm. RNP 10= 10 nm.
• This is widely used in terrain
approaches.

35. • RNP (Required Navigation Performance):
measures the required accuracy of the
navigation system in order to fly in that route.
• ANP (Actual Navigation Performance):
measures the actual accuracy of the on-
board navigation system. There must be a
slight variability due to different manufacturer
settings (systemic error).

36. From the above diagram, it illustrates that RNAV (aRea Navigation) allows
the aircraft not following segments to customise route. The RNP type
navigation further allows aircraft to fly at the best route possible, within a
certain limit.

38. ILS
• Instrumental Landing
System
• Glideslope: The path that
an aircraft follows during
landing.
• The localiser/VOR
beacon sends a radio
signal at a certain angle
at a certain frequency.
• It allows the pilot to judge
whether it is in line with
the runway or not under
a very poor visibility
conditions.

39. ILS

40. ILS
• In the flight display
(which shows the
airspeed, altitude to the
pilot), the aircraft
received the certain
signals only if they are
too high/low or
left/right.
• The FD then informs
the pilot the position
the aircraft compared
to the glideslope.

41. When you need ILS…

42. ILS
• http://www.youtube.com/watch?v=VgnRrm
mP2oU&list=UUDmiTnf0ZJOCr4JZ6wFlw
8Q&index=10&feature=plcp

43. End of Air Navigation

44. Air Traffic
Control

45. Not this!

46. Aims:
• What is ATC
• The role of ATC
• How ATC works
• How airspace are organised and
categorised
• Some application of special ATC service
• Future technologies on air traffic control

47. What is ATC?
• Air traffic control (abrv: ATC) is a
ground-based service to regulate air traffic
in an organised and safe fashion inside a
specific airspace.
• They also provide airspace/meteological
information of the region.

48. Speak English!
• The ICAO (International Civil Aviation
Organisation) rules out that English should be
used within ATC communication.
• In many other countries where English is their
secondary or third language, their local
language is usually used instead amongst
local pilots.
• ICAO has unified alphabets (known as NATO
alphabets) that are used in the radio
transmission.

50. Different controllers
• Air traffic control is
composed of these parts:
• Clearance delivery: Files
the route of the flight, i.e.
taxi route, jetway, time of
departure/arrival etc.
• Ground : Taxiing, ground
vehicles
• Local control (Tower):
Clears aircraft to land/take-
off. They control the runway
and its nearby airspace.

51. Different controllers
• Terminal controller: It handles
airspace up to around 20,000ft,
radius of around 100nm from
the airport. They usually
coordinate traffic
inbound/outbound of the
airport.
• Area control: Known as
“centre”, which provides flight
traffic service for high altitudes,
above 20,000ft. They are
responsible traffic within a FIR
(Flight Information Region),
which is a large airspace
assigned by ICAO.

52. ATC in the UK
• Traffic services are provided by NATS
(National Air Traffic Service).
• They are responsible for all traffic flying
into/from/over the UK.
• They are also responsible for Kent/London
airspace – one of the top 3 busiest
airspace in the world.

53. How it works?
• Let us start from the very beginning of a
typical commercial flight…

54. Flight planning
• It is similar
when we want
to drive from
Birmingham to
Bristol – we use
motorways, exit
at certain
junctions and
estimate a
rough journey
time.
• Flying also
needs planning!

55. Flight planning
• Flight dispatcher will write up a flight plan for each
individual flight. Contents include:
• Time for T/O and ETA (Estimated time arrival)
• Routes (airspace transition, airspace rights, jetways,
backup airport, waypoints)
• Routes (great circle, jetstream, loxodrome)
• Weather (are there any storm, extreme temperature)
• Payload (zero weight, maximum T/O weight)
• Cruising (True airspeed, flight levels including RVSM)
• Fuel on board (fuel for flying, emergency)
• Economy (!!) (Fuel efficiency, rate of climb, throttle,
balance between time and cost)

56. Airspace
• Routings:
As we discussed before, airways are air routes laid out
with nav - aids (VOR beacons, etc.) They are usually 10
nautical miles wide, and are controlled airspace (VFR
flights have to report to ATC).
• Airspace classes:
Airspace in the world are divided according to political,
military or commercial reasons:

57. Airspace
Classes Controlled? IFR/VFR ATC
Clearance
Traffic
separation
A Yes IFR only Required Provided to all
B (Not
existing in
UK)
Yes Both Required Provided to all
C Yes Both Required Provided to all
IFR/SVFR
D Yes Both Required Provided to all
IFR/SVFR
E Yes Both Required for
IFR/SVFR
Provided to all
IFR/SVFR
F No Both except
SVFR
Not required Provided to all
IFR/SVFR
G No Both except
SVFR
Not required Not provided

58. British Airspace
• The UK has two special airspace classes that
does not fall into the ICAO categories
(although most of the world also have similar
classification):
• Aerodrome Traffic Zone: It is based around
the airfield with busy inbound/outbound
traffic. Pilot has to contact with the tower
before transition into such airspace.
• Military Traffic Zone: It lies around the
military base. It is treated as a controlled
airspace.

59. Airspace

60. Departure
• The pilot has to initiate his flight plan by
obtaining clearance from the “Clearance
delivery” before push-back and taxi.
• The Clearance Delivery gives information to
the pilot about the weather, route, runway
closure etc.
Often the CD loops the recording of the ATIS
in busier airports. (Automatic Terminal
Information System)

61. Departure
• After doing pre-take off
checks and
preparation, the pilot
will now contact
“Ground controller” to
obtain permission to
push back and taxi out.
• Taxiing is probably the
hardest among all – the
amount of aeroplanes
attempting to taxi at the
same time is
enormous!

62. Take off/Landing
• The pilot halts behind the threshold
line and change its frequency to the
Tower Controller.
The pilot at this point should have
done their pre-take off checks (i.e.
fuel, flaps, TOGA throttle, autopilots
etc.)
• The tower controller, in a bigger
airfield, is situated among with the
other ATCs. In smaller aerodrome
often he is situated at a small van
near the runway so that he could
visually check if the runway has
been cleared.
• If an aircraft has to taxi across an
active runway, it must first gain
permission from the Tower
Controller.

63. STAR/SID
• After take off the pilot tunes his frequency
again after leaving the runway airspace. He
contacts the local terminal control.
• The control extends around 100nm from the
airport, and up to 20,000ft (FL200).
• The terminal control is mainly responsible for
two things:
To ensure that departing aircraft are at the
right altitude as they are handled off;
To ensure the arriving traffic is at the right
route, pattern and rate of descent.

64. STAR/SID
• SID (Standard Instrument Departure) are
set of regulations that IFR traffic complies
after taking-off. The ATC usually gives the
vector which the traffic should head to:
“Speedbird 001, fly heading 110 and
ascend and maintain FL170 prior to
making any turns.”

65. STAR/SID
• STAR (Standard Terminal Arrival Route) is
the published regulation that pilots follow
before arriving the airport.
• It could be sub-classified into two
categories: Instrumental approach or
visual approach.
• Similar to SID, it is a set of waypoints/
visual landmarks that a traffic follows
before cleared for landing.

67. Cruising
• Above FL200 the airspace class is Class A
– it is controlled and only IFR is allowed.
• The en-route/ area control, who is
responsible for each FIR, is taking control
of the aircraft’s cruising stage.
• They are responsible to allow the aircraft
to fly in their planned altitudes and at the
same time maintain separation both
vertically and horizontally.

68. Cruising
• RVSM (Reduced Vertical Separation Minima)
• Before when airborne instruments were not
as accurate as it is now, aircraft are
separated far apart (i.e. 3000ft) to avoid
collision.
• This wastes a lot of precious airspace!
• As pitot tubes are more accurate and reliable
now, we can measure the altitude in a more
reliable and precised way.
• We can reduce the separation to increase air
capacity.

70. Cruising
• Again the pilot has to comply with ATC
instructions. Usually the route has already
been inputted to flight computer.
• Area chart (high altitude) are usually used.

72. Radios
• ATC range from 1nm to roughly 300nm.
Some FIR are as large as a time zone!
• VHF/UHF is used in ground controls.
This is because of the short range and
high clarity.
• MF/VHF is used for area controls.
121.50MHz is reserved as emergency
frequency.

73. Transponder
• Little dots are used to represent an aircraft in
the ATC screen. However these dots does
not tell us what exact flight it is.
• A squawk code is allocated to each flight. The
pilot enters the code into their transponder.
• 7700 is the emergency squawk code.

74. Callsign and registration
• Each aircraft has its unique registration.
The letters are based on which country it
is registered at.
• For example:
G-CFKG (UK); D-ERT (Germany) etc.
• It is read out using the NATO alphabets.
• In practice some pilots identify themselves
using the 3 last alphabets of the aircraft
reg.

75. Callsign and registration
• Similar to all radio communications,
callsign is used to identify exactly where
the message was coming from.
• Each flight/airline has an unique callsign.
• I.e. BA 053 would be “Speedbird Zero-
Five-Three”, LH 034 would be “Lufthansa
Zero-Three Four”

76. Callsign and registration
• There are special cases:
• Aircraft with T/O weights more than
300,000lbs must append “Heavy” behind their
callsign, i.e. “Airfrance 001 heavy”.
• Air ambulance must append “Pan Pan
Medical Speedbird One Niner Three” to
indicate that it is urgent and there is a
medical situation onboard.
• VIP transports have their own callsign, i.e.
“Air Force One” for US’s president plane.

77. Emergencies
• There are two degree of emergency:
Problem: “London Centre, we have got a
slight problem with…”
Pan-pan: A condition concerning the safety
of an aircraft or other vehicle, or of some
person on board or within sight, but which
does not require immediate assistance.

78. Emergencies
• Mayday: A condition of being threatened
by serious and/or imminent danger and of
requiring immediate assistance
• Non – traditional methods includes:
• “Trangular Distress Pattern” – making
120 degree turn several times.

79. Future ATC
• The sky is more packed with aircrafts. We
need a new way to organise the
increasingly difficult traffic in an efficient
and organised fashion.
• New technologies has been developed.
Some are digital signals that aims to
develop airspace where radios are not
possible; some are computerised ATC!

80. Transatlantic Flights
• Since early 20th century many aviators
attempted to cross the Atlantic Ocean with
their bi-plane.
• The violent weather and the few thousand
miles ocean simply make it impossible.
• Scheduled jet flights commenced in 1957.
After aviation laws on transatlantic flights
were loosened in 1980s, many flights now
compete in trans-Atlantic market.

81. Transatlantic routes
• It is known as NAT (North Atlantic Tracks)
• Unlike other airways, the NAT are changed daily.
This is based on jetstream etc. to reduce fuel burn.
• Aircraft has to enter the route at special entrance
points.
• As there are no beacon in the ocean, ATC
separation are simply not possible.
Time separation (of 10 minutes) is used instead.
The crew has to report their position and the
expected time that they reach the next waypoint.

82. Transatlantic routes

83. Controller-pilot datalink
communication
• If a tower controls a large airspace, then
the pilot will have to use the same
frequency for a long time.
• As the airspace is large, the frequency
may also be used by the nearby tower,
causing confusion.
• The voice clarity is also a problem.
• The ATC is unable to handle anymore
traffic.

84. Controller-pilot datalink
communication
• Instead of using radios, a
HF carrier wave transmits
digital signals to the
aircraft.
• The pilot and the ATC can
transfer information
quicker and in indefinite
format (any texts).
• New airways can be
developed where terrain
are very rough (i.e. Mount
Everest, oceans etc.)

85. • Other systems, i.e.
ADSB (Automatic
dependent surveillance
broadcast) uses
satellite, radar and
airbourne nav to
generate a digital
display of information.
• It aims to improve
‘visibility’, better flow of
traffic, higher accuracy
and improved spacing.

86. Video
• http://www.youtube.com/watch?v=-
IS5dCkGXZI
• http://www.youtube.com/watch?v=sgOZN
UoT9L4

87. End of Air Traffic Control