Internship Report Pakistan Civil Aviation

Submitted by:

            Syed Muhammad Zaidi

            Electronic Engineering

List ofContents

Introduction……………………………………………………………………………

NavigationalAids………………………………………………………………………………………….

HF (high frequency)section…………………………………………………………………………………..

VHF/UHFsection……………………………………………………………………

Radar……………………………………………………………………………………

Pakistan Civil Aviation Authority is a regulatory authority who is responsible to regulate

all aspects of civil aviation in Pakistan.CAA head quarter is situated in terminal 1 of JinnahInternational Airport in Karachi.

Pakistan Civil Aviation Authority is a Public sector autonomous body working under the

Federal Government of Pakistan through the Ministry of Defence. It was established on7th December, 1982 as an autonomous body. Prior to its creation, a Civil AviationDepartment in the Ministry of Defence used to manage the civil aviation relatedactivities.

ELECTRONIC Engineering Department(EED)

It holds following major functions at CAA:

· Procurement of all new aviation equipments (Radars, Voice logging systems,ILSetc) and thorough testing of each equipment after purchase.

· Providing on field repair and maintenance facilities all over Pakistan through itstrained personnel.

· Workshops for extensive repair facilities at EED in case the equipment could notbe repaired at site.

It subdivided into following sections also: ∙ Navigational Aids

· HF(High Frequency ) Section· VHF/UHF Section· Radar Central Workshop

Our INTERNSHIP at EED was designed in such a way so that that we could understand thefunctionality of each section. We spent the allocated time in each section and got familiarwith the functioning of equipments. Following is the short detail of each section‘s

equipment and operation.

Navigational aid section

The department of navigational aid deals with en route navigation and terminal

navigation.

En Route Navigation:

When airplane is successfully in air after takeoff then navigational aid guide aircraft toits destination known as En route Navigation. It has following equipments:

❏ N.D.B(Non directional beacons)❏ VOR(VHF Omni directional Range)❏ DME(Distance measuring equipment)

N.D.B(Non directional beacons):

           It is a radio transmitter at a known location and used as an aviation and marine

navigational aid. It send Morse code of desired landing city at some frequency to pilot.Itis operating at a frequency between 190 KHz to 1750 KHz. It operated in all direction.Ituses AM modulation and has maximum output power 25 watt to 5k watt.

At MULTAN, It is operated at frequency of 387khz andtransmitted Morse Code MICE TANGO (­ ­  ­) at every 8 seconds and it isnormally utilized by low flying aircrafts and it has 0.2k watt maximumoutput power. It has 200 to 300 NM coverage and maximum forwardpower is maximum and has zero reflection and 90% modulation depth.

NDB signal follow curvature of earth and it can be received at

maximum distance at low altitude (major advantage over VOR).

NDB signal are affected by many thing:

❏ Night affect❏ Interference❏ Mountain affect❏ Coastal affect

 Night affect:

Radio waves reflected back from Ionosphere at night can cause signal strengthfluctuated 30 to 60 NM (54 to 108 km) from from transmitted, especially justbefore and after sunset.

ADF(Automatic Direction Finder):

        It is installed at aircraft and determines direction of NDB station.

It also determined distance of aircraft from NDB station:

Distance=Speed*time

*time=60*(number of minutes flown/degree of bearingchange)

Example:

          Germany Rorberg airport has two runways (Runway

18&36).Runway 18(approach from North) has 2 NDB’s with ILS.These are called“Romeo” and “Oscar Golf”. Runway ‘36’ (approach from South)has only one NDBcalled “Golf Sierra” and no ILS.

❏ Romeo operated at 414 kHz AM and has Morse Code “.-. “

❏ Oscar Golf operated at 328 kHz AM and has Morse code “--- --.”

Models of NDBs. used by CAA are:Aerocom 5401, 5034 ,Nautel ND-500, ND-2000 Southern Avionics SS – 1000

VOR(VHF Omni directional Range) It is used as a navigation system, a pilot can navigate from point A to point B. VOR stationis identified by Morse Code.VOR is actually a radio aid that provide info about:

❏ Azimuth❏ Course❏ To-from to the VOR station

Azimuth:It is clockwise angle between magnetic north and line connecting the VOR and aircraft. In aircraft, indication is displayed on “Omni bearing Indicator”Course:VOR provide center line to pilot.

To-from to the VOR station:It tells whether an aircrafts is approach to or moving away from VOR station.

Operating Frequency:It operates in VHF band range from 112 to 118 MHzIn CAA, its 116 MHz

Basic Principle of Operation:VOR facility transmitted two 30Hz signals at the same time.

❏  Reference Signal❏ One 30Hz signal in all direction (constant phase)❏ Variable Signal

❏ One 30Hz signal is rotated about the station.Airborne equipment receives both signal at phase difference b/w two signals & interpretthe result as the “radial” from the station.

VOR has two types:❏ CVOR(Conventional VOR)❏ DVOR(Doppler VOR)

Comparison between D- VOR & C-VOR:

Doppler VOR beacons are inherently more accurate than Conventional VORs because theyare 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 CVORbeacon, bounces off a building or hill, the aircraft will see a phase that appears to be atthe phase centre of the main signal and the reflected signal, and this phase centre willmove as the beam rotates. In a DVOR beacon, the variable signal will, if reflected, seem tobe two FM signals of unequal strengths and different phases. Twice per 30Hz cycle, theinstantaneous deviation of the two signals will be the same, and the phase locked loopwill get (briefly) confused. As the two instantaneous deviations drift apart again, thephase locked loop will follow the signal with the greatest strength, which should be thatdue to the line-of-sight signal. This will depend on the bandwidth of the output of thephase comparator in the aircraft. Hence some reflections can cause minor problems, butthese are usually about an order of magnitude less than in a CVOR beacon.

CVOR

DVOR

DME(Distance Measuring Equipment): It is transponder based radio navigation technology. It measures Distance fromaircraft to ground beacons. It provides indication of slant range(in NM) of anaircraft from a ground DME facility. It is identified by Morse Code.

It has two components:

❏ One is installed in aircraft and it is Interrogator❏ Second is ground based Transponder

Operation Frequency:

It is operated at frequency between 926 to 1213 MHz.Interrogation and Replyfrequency are associated frequency with at least 1 MHz separation.It hascoverage of about 200NM and ground based transponder capable of handling atleast 100 aircrafts. It measures distance by timing the propagation delay of VHFor UHF radio signals. Aircraft use DME to determine their distance from aland-based transponder by sending and receiving pulse pairs - two pulses of fixedduration and separation. The ground stations are typically co-located with VORs.A typical DME ground transponder system for en-route or terminal navigationwill have a 1 kW peak pulse output on the assigned UHF channel.

Terminal Navigation:

The navigation techniques used to help the aircraft in landing is known as terminalnavigation. The whole set of equipment used in the process is known as InstrumentLanding System (ILS).

It consists of Localizer, Glide Scope, TDME and Marker Beacons.

Guidance Info: Localizer, Glide scope

Range info: Marker beacons, PAPI approach lights, touchdown lights, centerline lights,runway lights.

Localizer: It provides center line info to pilot and it consists of 14-log periodicdipole antennas and installed at the stop end of runway. It can cover 25or 10 NM andhave transmitting frequency in VHF band (108 to 112 MHz). It is identified by its Morsecode like for Multan is IMT and fro Karachi is IKC.Principle of Operation of Localizer:A localizer antenna array is normally located beyond the departure end of the runwayand generally consists of several pairs of directional antennas. Two signals aretransmitted on one out of 40 ILS channels between the carrier frequency range 108.10MHz and 111.95 MHz (with the 100 kHz digit always odd). One is modulated at 90 Hz,the other at 150 Hz and these are transmitted from separate but co-located antennas.Each the left of the runway centerline, the other to the right antenna transmits a narrowbeam, one slightly to the left of the runway centerline, the other to the right.

Glide Scope:It is installed at the approach end of the runway and provide “Glide Path Angle” info topilot. The glide path angle is adjusted to project an angle of 2’ or 4’ above horizon. ForMultan, it is 3’.Its transmitting frequency in UHF band ranging b/w 328 to 332 MHz. Glide scopefrequency is paired with specific localizer frequency.Upper side of the course is modulated at 90Hz and lower side modulated at 150Hz.

Marker beacons:They operated at frequency of 75 MHz.It consists of:

1. Outer marker beacons2. Middle marker beacons

3. Inner marker beacons

Outer Middle InnerMod tone 400HZ 1300HZ 3000HZKeying - - O-O- OOOOOOId PURPLE/BLUE AMBER WHITECoverage 600m 300m 150m

TDME:Terminal Distance Measuring Equipment (TDME) gives the information of distancefrom touch down point. Terminal DME, referred to as a TDME in navigationalcharts, is a DME that is designed to provide a 0 reading at the threshold point ofthe runway, regardless of the physical location of the equipment. It is typicallyassociated with Glide Slope.

Visit to Navigational Aid Section and Control Tower:

During our Internship, we have visited Navigational Aid Section of CAA at Multan International Airport and also see the ongoing up gradation work progress at Multan airport. We have seen the installation of Rotunda at domestic arrivals and visited CIP lounge while our lectures have held at OCC center. We have visited CCR room and get brief info about PAPI lights current regulator. We have also visited ECR(Equipment Control Room) and got familiar with aeronautical message handling system(AMHS) and have visited ATC control room.

HF SectionHigh frequency (HF) radio provides aircraft with an effective means of communication over long distance oceanic and trans-polar routes. In addition, global data communication has recently been made possible using strategically located HF data link (HFDL) ground stations. An aircraft HF radio system operates on spot frequencies within the HF spectrum. In the HF range (3 MHz to 30 MHz) radio waves propagate over long distances due to reflection from the ionized layers in the upper atmosphere.

HF section deals with the equipment of direct communication in Long Range, providing maintenance repairing and upgrading of HF communication equipments, for four purposes:

• Ground to Air Domestic

• Ground to Ground Domestic

• Ground to Air International

• Ground to Ground International

VHF/UHF Section

This section deals with all the equipments of VHF/UHF used for the communication between Air traffic Control to the plane or in other words ground to air communication. The maintenance of all the VHF/UHF equipments from all over Pakistan comes under this department. There are various types of antenna used in Communication of VHF/UHF, like whip antenna, long wire antenna, umbrella antenna, half and full dipole antenna, VHF extended antenna etc. Whereas, the general range of Frequencies used in CAA is from 118MHZ to 136 MHz.

Radar(Radio detection and ranging)

Radar is termed as “radio detection and ranging”. It is an equipment which is used to determine range, altitude, direction and speed of an objects like aircrafts, missiles etc

The radar dish/antenna transmits pulses of radio waves or microwaves which bounce back from any object in their path. The object returns tiny part of the wave’s energy to a dish/antenna which is usually located at the same site as transmitter.

Radar functions:

• Normal radar functions:

1. Range (from pulse delay)2. Velocity (from Doppler frequency shift)3. Angular direction (from antenna pointing) • Signature analysis and inverse scattering:4. Target size (from magnitude of return)5. Target shape and components (return as a function ofDirection)6. Moving parts (modulation of the return)7. Material composition

Radar classification:

In Pakistan, we used two types of Surveillance radars.❏ Primary surveillance radar❏ Secondary surveillance radar

Primary Surveillance Radar:It can detect any object in its operating frequency area by transmitting EM waves to the object, after striking an object EM waves bounce back to the ground transmitter and object can be detected.

Secondary Surveillance Radar:It is used for identification and detecting altitude of an object in its path by usinginterrogator and transponder, the interrogator has carrier frequency of 1030MHz andhas 1090MHz frequency of reply transmission.

Pakistan has 3 PSR and 6 SSR. They cover whole Pakistan.

RUSSIAN S-300 PMU-1 SURFACE TO AIR MISSILE

❏ The long range surveillance radar tracks object over arange of 185 miles and relays info to the commandvehicle which can assess potential target.

❏ A target is identified and command vehicle orders theengagement radar to launch missiles

❏ Launch data is sent to best placed of battalion’s sixlaunch vehicles and it releases two surface to air missiles

❏ Engagement radar helps guide missiles towards target

.It can guide up to 12 missiles simultaneously.