This document provides an overview of air traffic control (ATC) including: 1. It introduces ATC and its primary purposes of separating aircraft to prevent collisions, organizing traffic flow, and providing pilot support. 2. It summarizes key ATC concepts like ICAO, airspace classifications from A-G, controlled and uncontrolled airspace, and services like aerodrome/tower, area, and approach control. 3. It concludes that air traffic controllers play a vital role in safety by preventing collisions and following standardized rules and classifications to efficiently guide aircraft through the airspace.

1. Table of contents
Introduction……………………………………….2
Contents
ICAO…………………………………………….3
Air Traffic Services………………………..4
Airspace Classification…………………..6
ICAO Standard Semi-Circular Levels..7
Local Control(Aerodrome)…………….8
Area Control………………………………..9
Conclusion………………………………………….10
Bibliography………………………………………..11
1

2. A
Introduction
ir traffic control (ATC) is a service provided by ground- based
controllers who direct aircraft on the ground and in the air. The
primary purpose of ATC systems worldwide is to separate
aircraft to prevent collisions, to organize and expedite the flow of traffic,
and to provide information and other support for pilots when able. Air
traffic controllers are persons who operate the air traffic control system
to expedite and maintain a safe and orderly flow of air traffic and help
prevent mid-air collisions. They apply separation rules to keep each
aircraft apart from others in their area of responsibility and move all
aircraft efficiently through 'their' airspace and on to the next.
In many countries, ATC services are provided throughout the
majority of airspace, and its services are available to all users (private,
military,
and
commercial).
When
controllers
are
responsible
for
separating some or all aircraft, such airspace is called "controlled
airspace" and "uncontrolled airspace" where aircraft may fly without the
use of the air traffic control system. Depending on the type of flight and
the class of airspace.
Their immediate concern is safety, but controllers also must direct
planes efficiently to minimize delays. Some regulate airport traffic
through designated airspaces; others regulate airport arrivals and
departures.
2

3. I
ICAO
CAO is stand
for International Civil Aviation Organization.
International Civil Aviation Organization is a special agency that
codifies
the
principle
and
technique
of
international
Air
Navigation. The Headquarters are located in the Quartier International
of Montreal, Canada.
The
ICAO
Council
adopted
and
recommended
practice
air
navigation, infrastructure, flight inspection to prevent interference,
border crossing procedure, air classification, and traffic control mostly
about rule of airspace that been signed and agree by 52 state on
Chicago Convention on 1944 that established rules of airspace, aircraft
registration and safety. The Convention later been revised eight times.
The latest is on 2006. The Convention also support eighteen annexes
that are amend regularly by ICAO. ICAO also defined an International
Standard
Atmosphere
temperature,
density
model
and
for
standard
viscosity
atmosphere. ICAO also introduced
with
variation
altitude
the currently
in
pressure,
the
earth
adopt airspace
classification. They are all defined in term of IFR and VFR
3
of

4. Air Traffic Services
A
ir Traffic Services or ATS is a generic term which
encompasses Air Traffic Control ATCO’s, Flight
Information, Alerting Service and Air Traffic Advisory. The
Objective of The Air Traffic Services are to prevent aircraft
from colliding each other and obstructions in the maneuvering area,
expedite and maintain flow of air traffic, provide advice and information
for the safety of aircraft and control of the flight. Air traffic control
service including area, approach and aerodrome control services.
Provided by HF and VHF. Air Traffic Services that are provided in
Malaysian is Kuala Lumpur and Kota Kinabalu Flight Information Region
FIR that been recommended by ICAO that been state in Annexes
Document.
To
understand the ATS provided, one need to know the various type of
Airspace Designated.They actually Divided by Two:-
Control Airspace - Controlled airspace is an aviation term used to describe airspace in
which ATC has the authority to control air traffic, the level of which varies with the different
classes of airspace. The term "controlled airspace," by the way, doesn't mean that somebody or
some agency is up there controlling traffic, but controllers have a pretty good idea of what is up
there. Use of our national air traffic control (ATC) service is mandatory in Class A airspace that
begins at 18,000 feet MSL and extends upward to 60,000 feet MSL. Altitudes at 18,000 feet MSL
and above, in Class A airspace, are commonly referred to in thousands of feet as "Fight Levels,"
abbreviated FL. For example, flight level two zero zero, or FL 200 = 20,000 feet MSL, FL 600 =
60,000 feet MSL, etc.
Control Airspace usually exists in the immediate vicinity of busier
airports, where aircraft used in commercial air transport flights are climbing
out from or making an approach to the airport, or at higher levels where air
transport flights would tend to cruise. ICAO classifies airspace in seven
classes from classes A to G. Controlled airspace is classes A to E, in order
of decreasing ATC regulation of flights. Flight under instrument flight rules
(IFR) is allowed in all controlled airspace. Flight under visual flight rules
(VFR) is permitted in all airspace except A.They are generally 3 types of
Control Airspace:- Airways, CTR and TMA.
4

5. Uncontrolled space - Uncontrolled airspace is an aviation term to describe airspace
where an Air Traffic Control(ATC) service is not deemed necessary or cannot be provided for
practical reasons. According to the airspace classes set by ICAO both class F and class G airspace
are uncontrolled space. It is the opposite of controlled airspace.
o
Air Traffic Zone(ATZ) is the part of Airspace encompassing the Aerodrome
circuit and the holding areas over the designed airport navigation aid. It provided
protection to all flight within the vicinity of the aerodrome circuit. The main airspace is a
zone 5 nautical miles in radius from the surface to 3000 feet .
o
The control Zone(CTR) is an aviation term that describe a volume of control
Airspace or Approach control normally around airport extend from the surface to
specific upper limit established to protect air traffic To and From that airport. Aircraft can
only fly in it airspace after receiving a specific clearance from ATC.That mean what
aircraft and to ensure they are aware of each other
o
Terminal control Area (TMA) is an aviation terms to describe a volume of
control airspace set up at the airways in the vicinity of one or more airport and Control
Area that require more air classification. A Control Area is an aviation term that describe
a volume control airspace Control Area are useful where there are busy airport located
together. In this case a single control area will be used that known as Terminal
Manouvering Area (TMA).
5

6. Airspace
Classifications
T
he world’s navigable airspace is divided into three-dimensional
segments, each of which is assigned to a specific class. On March 12,
1990, ICAO adopted the current airspace classification scheme. The
classes are fundamentally defined in terms of flight rules and interactions
between aircraft and Air Traffic Control (ATC). Some key concepts are:
Separation: Maintaining a specific minimum distance between an aircraft and another aircraft or
terrain to avoid collisions, normally by requiring aircraft to fly at set levels or level bands, on set
routes or in certain directions, or by controlling an aircraft's speed.
Clearance: Permission given by ATC for an aircraft to proceed under certain conditions contained
within the clearance.
Traffic Information: Information given by ATC on the position
Most nations adhere to the classification specified by the International Civil Aviation Organization
(ICAO) which places further rules on air navigation for reasons of national security or safety are
described below:Class A: All operations must be conducted under Instrument Flight Rules (IFR) and are subject to
ATC clearance. All flights are separated from each other by ATC.
Class B: Operations may be conducted under IFR or Visual flight rules (VFR). All aircraft are subject
to ATC clearance. All flights are separated from each other by ATC.
Class C: Operations may be conducted under IFR or VFR. All flights are subject to ATC clearance.
Aircraft operating under IFR and VFR are separated.
Class D: Operations may be conducted under IFR,or VFR. All flights are subject to ATC clearance.
Aircraft operating under IFR and VFR are separated from each other, and are given traffic
information in respect of VFR flights. Flights operating under VFR are given traffic information in
respect of all other flights.
Class E: Operations may be conducted under IFR or VFR. Flights under VFR are not subject to ATC
clearance. As far as is practical, traffic information is given to all flights in respect of VFR flights.
Class F: Operations may be conducted under IFR or VFR. ATC separation will be provided, so far as
practical, to aircraft operating under IFR.
Class G: Operations may be conducted under IFR or VFR. ATC separation is not provided.
Classes A-E are referred to as Controlled Airspace. Classes F and G are Uncontrolled Airspace.
6

7. Q
ICAO Standard
Semi-Circular Levels
uadrantal and semicircular rules is a flight level that is the
nominal altitude of an aircraft that opposed the sea level. Before
the pilot must recalibrate the altimeter according to the local air
pressure from time to time in different region and if this isn’t done
different aircraft maybe flying at the different height even though their
altimeter shown at the same altitude. More dangerously different aircraft
maybe flying at the same height even though their altimeter show
different height. Flight level solve this problem by defining altitude based
on standard pressure that is called Quadrantal and Semi-circular rules
Quadrantal rules flight level are 500 feet
but to further ensure
separation of aircraft, aircraft travelling in different region in level flight
are required to used flight level according to the quadrantal rules as
follow :Track 000 – 089′ – odd thousand feet
Track 090 – 079’ – odd thousand + 500
Track 180 - 269’ - even thousand feet
Track 270 - 359’
even thousand + 500
And it’s the same with semi-circular. it just the different
circular
are divided into 2
is semi
track. Quadrantal rule been divided
track and semi circular rules been divided by 2 track:Track 000 – 179 – odd thousand feet
Track 180 – 359 – even thousand
7
by 4

8. A
Local Control
(Aerodrome)
n Aerodrome or Airfield is a term for any location from which
aircraft flight operations take place, equipped with control tower.
Including any runaway, taxi tracks, aprons, buildings,
installations, and equipment intended to be used either wholly or
in part for the parking, maintenance, arrival, departure, and surface movement
of aircraft . When used in the provisions relating to flight plans and ATS (air
traffic services). The term is used and designated as in ICAO Annex 14 to the
Convention. The Standards and Recommended Practices were based on
recommendations of the Aerodromes, Air Routes and Ground Aids Division,
their physical characteristics and their operation.
Tower controllers control aircraft within the immediate vicinity of the
airport and use visual observation from the airport tower. The tower’s airspace
is often 5 nautical mile radius around the airport, but can increased greatly in
sized and shape depending on traffic configuration and volume
8

9. Area Control
A
rea controllers are responsible for the safety of aircraft at higher
altitudes, in the phase of their
flight.In most nations they are
known as “area” or “en route” controllers. Airspace under the
control of area controllers is split into sectors. Each sector will be managed by
at least one Area controller. This can be done either with or without the use of
radar; radar allow a sector to handle much more traffic, however Procedural
control is used in many areas where traffic levels do not justify radar.
Procedural Control :- is a method of providing air traffic control service without the use of radar. A
system using calculation and position report of aircraft flying along the airways .
Radar Control Service :- is a method of providing air traffic control
services with the use of radar. uses electromagnetic waves to identify the
range, altitude, direction, or speed of both moving and fixed objects such as
aircraft, ships, motor vehicles, weather formations, and terrain.
Using procedural control, the controller must maintain a mental picture
of the location of aircraft based on each aircraft's flight progress strip, which
contains its route, altitude and estimated times
over reporting points. That information is compared
against all other aircraft in the sector to determine
if there are any conflicts. For aircraft that conflict,
the controller issues an altitude, speed or routing
change that both separates the conflicting aircraft
from each other, while still remaining separated
Flight Strip
from all others. After all conflicts have been resolved in this way, the sector is
considered "separated" and the controller only needs to check again for
conflicts when new aircraft are added.
9

10. Conclusion
A
ir Traffic Controllers play an important role to prevent aircraft from colliding into
each other.All the Rules ,regulations, Standard practices are being recommended by
ICAO depending on their classification
The Tower or Aerodrome position are split into many different position such as Flight
Data/Clearance Delivery, Ground Control and Local Control; at busier airport a limited radar
approach control position maybe needed. The roles of position are:Flight Data: issues IFR flight plan clearance, usually prior to taxi
Ground : issues taxi instruction and authorized movement at the airport
Local (Tower): issues take off and landing instruction/clearance
Controllers shall monitors visually the aircraft as they approach this positions so that the
appropriate clearance will be issued with out delay. Aircraft initiates call to taxi for departing
flight/taxi instruction. Take off clearance issued. Aircraft reports on downwind leg and
cleared to final. pilot will be given his position .Base leg report if requested. final report. Long
final .Taxiing and parking instruction issued. Aircraft flying VFR normally joined the
Aerodrome circuit at 1,500. When aircraft is on the cruising altitude the Area controllers will
take over guiding the aircraft . Area Control Center (ACC), also known as a Center, is a
facility responsible for controlling instrument flight rules aircraft en route in a particular
volume of airspace (a Flight Information Region) at high altitudes between airport approaches
and departures.
10

11. Bibliography
1. For Books:
Author(s)
Year
Title
City
Publisher
AMC
Air Traffic Management
KL
AMC
2010
2. For Encyclopedias (no author)
Article Title
Year Encyclopedia Title
Publisher
Volume/Page(s)
Aircraft
Air Legislation and
Maintenance
1998 Airworthiness
Engineer’s Licence
Requirements
Aero
Precision
Resources
Vol.1, pp.1-66
3. For Internet Sources (no author)
Date
Article Title
URL (Internet Site Address)
(Year/Month/Day)
Airspace
Classification
Area Control
Center
Controlled
airspace
Air Traffic
Control
19 August 2008
aspmhelp.faa.gov/index.php/AirspaceClassification
26 January2010
http://en.wikipedia.org/wiki/Area_Control_Center
23 December 2009 http://en.wikipedia.org/wiki/Controlled_airspace
10 November 2009 www.newworldencyclopedia.org/Air_traffic_control
4. For Educated Person and Other Periodicals:
Name(s)
Position
Kol (B) Ramli Robani
Lecturer
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