0 [Date]

Internship Report on

Pakistan Civil

Aviation Authority

Ali Raza Internee at CAA

Multan Intl. Airport

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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)

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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

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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

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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.

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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

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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

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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

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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

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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

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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

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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.

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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.

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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.

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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

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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).

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COM:

This includes Secondary surveillance radar mounted on

primary surveillance radar.