CAA Pakistan

0[Date]
Internship Report on
Pakistan Civil
Aviation Authority
Ali Raza
Internee at CAA
Multan Intl. Airport

Internship Report on CAA Pakistan
THE ISLAMIA UNIVERSITY OF BAHAWALPUR ALI RAZA 1
Contents
CAA Pakistan
 Overview
 Function
Instrument landing system
 Localizer
 Glide slope
 Marker beacons
 Visual information
Navigational aids
 Equipment control room
 DVLS
 NDB
 VOR
 DME & TDME
 Control tower
Fire section
Radar Section
 PSR
 SSR
 COM (PSR + SSR)

CAA Pakistan_____________________________________________________________________________________
Overview:
he civil aviation authority was created in
December 1982 to handle all matters related to
civil aviation in Pakistan. In order to keep up
rapid advancement in the field of aviation, it was felt that an
autonomous body was required to bring the country’s
aviation infrastructure and facilities as par with international
standard.
Function:
The CAA not only serves as a regulatory body on behalf
of the government of Pakistan, its functions include
provision of services such as facilitation, air space
management, air traffic control, firefighting services,
planning, maintenance development of all civil aviation
infrastructures in the country. CAA ensures conformity to
the standard laid down by the international civil aviation
organization (ICAO), regard to flight safety and air traffic
control and navigation system.
T

Instrument Landing System (ILS)
he instrument landing system is the precise
control system which helps and guides the pilot
during landing of the aircraft.
Components:
The CAA categorized the components this way,
 Guidance information:
The localizer and glide slope.
 Range information:
The outer marker (OM), middle marker (MM), and
inner (IM) marker beacons.
 Visual information:
Approach lights, touch down and center line lights,
runway lights.
Localizer:
A localizer is one component of an instrument landing
system (ILS). The localizer
provides runway centerline
guidance to aircraft. A localizer
is an antenna array normally
located beyond the departure
end of the runway and generally
consists of several pairs of
directional antennas. Two
T

signals are transmitted on one of 40 ILS channels. One is
modulated at 90 Hz, the other at 150 Hz. These are
transmitted from co-located antennas. Each antenna
transmits a narrow beam, one slightly to the left of the
runway centerline, the other
slightly to the right. The localizer
receiver on the aircraft
measures the difference in the
depth of modulation (DDM) of the
90 Hz and 150 Hz signals.
Localizer information is
displayed on the same indicator
as of VOR information. When
tracking the localizer the pilot
turns towards the needle in the
same manner as with VOR navigation. In CAA MULTAN the
frequency used in localizer is 110.3 MHz and power is 15 Watts.
The localizer signal is normally usable by 18 NM from the field.
Glide Slope:
A glide slope station is an antenna array sited to one
side of the runway touchdown zone. The glideslope is the
signal that provides vertical guidance to the aircraft during
the ILS approach. The centerline of the glide slope signal is
arranged to define glide slope of approximately 3° above
horizontal (ground level). The
beam is 1.4° deep; 0.7° below the
glide slope centerline and 0.7°
above the glide slope centerline.
Tracking the glide slope is
identical to tracking a localizer.
The glide slope is normally
usable to a distance of 10 NM. IN
CAA MULTAN the frequency used
in glide slope is 335 MHz and power is 4 Watts.

Marker beacons:
 Blue outer marker:
The outer marker may be located between 3.5 to
6.0 NM from the threshold. The outer marker is normally
located at 3.9 NM from the threshold, except that where
this distance is not practical The modulation is repeated
Morse-style dashes of a 400 Hz tone (--) ("M"). The
cockpit indicator is a blue lamp
that flashes in unison with the
received audio code. The
purpose of this beacon is to provide height, distance,
and equipment functioning checks to aircraft on
intermediate and final approach.
 Amber middle marker:
The middle marker should be located so as to
indicate, in low visibility conditions, the missed approach
point, and the point that visual contact with the runway
is imminent, ideally at a distance of approximately 1,100
m from the threshold. The modulation is repeated
alternating Morse-style dots and dashes of a 1.3 kHz
tone at the rate of two per
second (•-•-) ("Ä" or "AA"). The
cockpit indicator is an amber
lamp that flashes in unison with the received audio
code.
 White inner marker:
The inner marker, when installed, shall be located so
as to indicate in low visibility conditions the imminence
of arrival at the runway threshold. This is typically the
position of an aircraft on the ILS as it reaches Category
II minima. Ideally at a distance of approximately 300 m

from the threshold. The modulation is repeated Morse-
style dots at 3 kHz (••••) ("H").
The cockpit indicator is a white
lamp that flashes in unison with
the received audio code.
Visual information:
 Approach lights:
These lights are located at end point of the runway.
These lights assist the pilot in transitioning from
instrument to visual flight, and to align the aircraft
visually with the runway centerline. As approach lights
counts runway end environment Pilot observation of
the approach lighting system allows the pilot to
continue descending towards the runway, even if the
runway or runway lights cannot be seen.
 Runway lights and center line lights:
Runway lights are located
on both sides of the runway,
and centerline lights are on
the center line of the large
runways, these lights are
covered by an unbreakable
transparent glass which is not
affected by wheels of
aircrafts. The intensity of these lights can be controlled
by a series circuit.
 Precision approach path indicator (PAPI) lights:
The PAPI is a light array positioned beside the
runway. It normally consists of four equal-spaced light
units color-coded to provide a visual indication of an
aircraft's position relative to the designated glideslope

for the runway. An abbreviated system consisting of
two light units can be used for
some categories of aircraft
operations. The international
standard for PAPI is published
by the International Civil
Aviation Organization (ICAO). At
night the light bars can be seen
at ranges of at least twenty
miles. Each light unit consists of
one or more light sources, red
filters and lenses. Each light unit emits a high-intensity
beam. The lower segment of the beam is red, and the
upper part is white. The pilot will have reached the
normal glide
path (usually 3 0)
when there is an
equal number of
red and white
lights. If an
aircraft is
beneath the
glide path, red
lights will outnumber white, if an aircraft is above the
glide path, more white lights are visible. Usually called
mnemonic.
“RED on WHITE you're alright, RED on RED and
you're dead.”
The intensity of above lights is controlled by
constant current regulators. All the runway light circuits
are connected in series to ensure the same intensity.
Similarly all centerline lights and approach lights are also

as runway lights. The ratings of constant current
regulator is as below.
THORN Airfield lighting DIAM 4000 single phase
Input = 400 V, 50 Hz, 83 A,
Output = 30 kW at 6.6 A, maximum output voltage =
4545 V, output current= 6.6 A, air as dielectric medium
and 5 stages of brightnesses.
Navigational Aids
Equipment control room (ECR):
Over view:
ECR is the main department of civil aviation, for wireless
communication. It deals with the communication regarding
air traffic and on board flight information. The dept. is the
central part of CAA, which also consist of the control tower
regarding the flight approach services (takeoff/landing/taxi).
ECR is basically controlling all the radio frequency
communication covering the range of entire Pakistan.it deals
with the wide range of frequencies and channels which are
being used at CAA for fir (flight information region) purpose.
Frequencies:
Different types of frequencies are used for
communication, which are:
 HF (High frequency) 3-30 MHz
 VHF (Very high frequency) 30-300 MHz
 UHF (Ultra high frequency) 300-3000 MHz

Radio frequencies used by CAA:
Communicators Main (MHz) Standby (MHz)
Tower controller 119.1 122.6
Radar frequency 123.3 127.3
VHF extended range 128.3 133.2
VHF emergency frequency 121.5 ------
Digital Voice Logging System (DVLS):
Digital voice logging system is a recording and archiving
system for all the necessary digital communication for
official record. It has 40 channels and a hard disk for data
storage.
Non-directional Beacon (NDB):
NDBs are basically a simple radio transmitter which
radiates a signal equally in every direction (hence 'non-
directional'). This signal is modulated with a Morse code
identity signal. This Morse code have information about the
identification of station. NDB signals follow the curvature of
the Earth, so they can be received at much greater distances
at lower altitudes, a major advantage over VOR. However,
NDB signals are also affected more by atmospheric
conditions, mountainous terrain, coastal
refraction and electrical storms, particularly
at long range. In Pakistan NDB frequency is
from 200 – 525 kHz. At Multan the NDB is of
Nautel Company and operates at 387 kHz
frequency. Its maximum power is 500 watts.
This Symbol denotes an NDB on an

aeronautical chart.
VHF Omni-directional Range (VOR):
VOR short for VHF Omni-directional range is a short
range radio navigation system for aircraft, enabling aircraft
to determine their position and stay on course by receiving
radio signals transmitted by a network of fixed ground radio
beacon, with a receiver unit. It uses radio frequencies in the
VHF band from 108 - 117.95 Mhz. VOR is the standard air
navigational system in the world used by both commercial
and general aviation. At Multan airport the frequency used
by CVOR is 116.7 MHz with 50 watts power.
The VOR encodes azimuth (direction from the station) as the
phase relationship of a reference and a variable signal. The
phase angle by which the AM signal lags the FM subcarrier
signal is equal to the direction from the station to the
aircraft, in degrees from local magnetic north, and is called
“Radial”. The intersection of two radials from different VOR
stations on a chart provides the position of the aircraft.
Comparison between D- VOR & C-VOR:
D-VOR are for hilly areas and C-VOR
are for plane areas. Doppler VOR
beacons are inherently more accurate
than Conventional VORs because they
are more immune to reflections from
hills and buildings. The variable signal, in
a DVOR, is the 30Hz FM signal. In a CVOR
it is the 30Hz AM signal. If the AM signal
from a CVOR beacon, bounces off a
building or hill, the aircraft will see a
phase that appears to be at the phase
center of the main signal and the reflected signal, and this
phase center will move as the beam rotates. In a DVOR

beacon, the variable signal will, if reflected, seem to be two
FM signals of unequal strengths and different phases. Twice
per 30Hz cycle, the
instantaneous deviation of
the two signals will be the
same, and the phase locked
loop will get (briefly) confused.
As the two instantaneous
deviations drift apart again,
the phase locked loop will
follow the signal with the
greatest strength, which should be that due to the line-of-
sight signal. This will depend on the bandwidth of the output
of the phase comparator in the aircraft. Hence some
reflections can cause minor problems, but these are usually
about an order of magnitude less than in a CVOR beacon.
Models of VOR used by CAA are: C-VOR: Wilcox 585BD-VOR:
Thomson-CSF 512-C, 512-D
Distance measuring equipment (DME and
Terminal DME):
DMEs are replacing marker beacons. The DME provides
more accurate and continuous monitoring of correct
progress on the ILS glide slope to the pilot, and does not
require an installation outside the airport boundary. Both
these devices are used for measuring the airplane distance
from the airport and threshold. The difference between
them is that: the DME is used to measure the distance from
the airport and having long range as compared to TDME,
while the TDME is the device used for distance measuring of
aircraft from threshold point of the runway.

The DME is composed of a UHF transceiver (interrogator)
in the aircraft and a UHF transceiver (transponder) on the
ground.
Control Tower:
Air traffic control (ATC) is a service provided by ground
based controller who directs aircraft on the ground and
through controlled airspace. 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
to. In some countries ATC may also play a security or
defense role or be run entirely by the military.
Center controllers are
responsible for climbing the aircraft
to their requested altitude while, at
the same time, ensuring that the
aircraft is properly separated from
all other aircraft in the immediate
area. As an aircraft reaches the
boundary of a center’s control area
it is “handed off” or “handed over”
to the next area control center.
After the hand off, the aircraft is
given a frequency change and
begins talking to the next controller.
This process continues until the
aircraft is handed over to the terminal controller (Approach).
The control tower communicates with the air craft as
well the ground services on the airport. The ground to ground
communication is through FM radio transmitter and receiver
and its frequency at CAA Multan is 121.8 MHz and ground to air
communication is through AM radio transmitter and receiver
and its frequency is 119.1 MHz.

FIRE SECTION
OSHKOSH Striker’s Specs:
 1500 gallon water tank,
 210 gallon foam tank,
 1500 lb. dry chemical,
 700 HP v8 diesel engine,
 250 liter. Fuel tank,
 4 cameras,
 5kv diesel generator (in case of emergency lights),
 Auto transmission,
 6 dry batteries,
 Top speed 120km, 80km in 40 seconds.

Radar Section
adar (Radio Detection and Ranging) is an object-
detection system which uses radio waves to
determine the range, altitude, direction, or
speed of objects. It can be used to detect aircraft, ships,
spacecraft, guided missiles, motor vehicles, weather
formations, and terrain. The radar dish or antenna transmits
pulses of radio waves or microwaves which bounce off any
object in their path. The object returns a tiny part of the
wave's energy to a dish or antenna which is usually located
at the same site as the transmitter. Radar is used on airport
as aircraft anti-collision systems and flight control system.
There are three types of radar used for flight control.
Primary Surveillance Radar (PSR):
Electromagnetic waves reflect (scatter) from any large
change in the dielectric constant or
diamagnetic constants. This means
that a solid object in air or a vacuum,
or other significant change in atomic
density between the object and what
is surrounding it, will usually scatter
radar (radio) waves.
PSR receive the following data:
 Aircraft range
 Aircraft Azimuth
The average coverage of PSR is 100 nautical miles.
R

Operating frequency:
Frequency Range of PSR is 2700 MHz to 2900 MHz and it
operates in “S” Band.
Secondary Surveillance radar (SSR):
SSR is a radar system used in air traffic control (ATC),
that not only detects and measures the position of aircraft
i.e. range and bearing, but also
requests additional information
from the aircraft itself such as
its identity and altitude. Unlike
primary radar systems that
measure only the range and
bearing of targets by detecting
reflected radio signals, SSR
relies on targets equipped with a
radar transponder that replies to each interrogation signal
by transmitting a response containing encoded data. SSR is
based on the military identification friend or foe (IFF)
technology.
The average coverage of SSR is 200 nautical miles.
Operating frequency:
1030MHz is used as a carrier frequency of the interrogation,
And 1090MHz is used as the carrier frequency of the reply
transmission (Transponder).

COM:
This includes Secondary surveillance radar mounted on
primary surveillance radar.

CAA Pakistan

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