Report

Pakistan International Airlines
(Avionics)
1
Introduction:
Pakistan International Airlines commonly known as PIA. PIA is a
Karachi based airline which is the national flag carrier of Pakistan.
Its main hub is Karachi while Lahore and Islamabad serve as its
secondary hubs.
The airline was founded on 23 October 1946 as Orient Airways,
initially based in Calcutta prior to the Partition of India. The airline
was nationalized on 10 January 1955 and was renamed as
Pakistan International Airlines. Its first international flight was in
1955, operating to London, via Cairo and Rome. PIA has a history
of milestones in aviation, it was the second Asian airline to acquire
a jet aircraft, a Boeing 707. More recently, it was the launch
customer of the Boeing 777-200LR.

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Base Maintenance
Fleet
As of April 2016 the Pakistan International Airlines fleet consists
of the following aircraft;
Aircraft Total
Airbus A310-300 5
Airbus A320-200 11
ATR 42-500 6
ATR 72-500 5
Boeing 777-200ER 6
Boeing 777-200LR 2
Boeing 777-300ER 3
Total 38

(Avionics)
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 Control Surfaces:
Aircraft flight control surfaces allow a pilot to adjust and control
the aircraft's flight attitude. Control surfaces work on the same
principle as lift on a wing. They create a difference in air pressure
to produce a force on the airplane in a desired direction.
There are two main control surfaces which as follows;
1. Primary control surfaces
2. Secondary control surfaces
Primary Control Surfaces:
o Ailerons:
Ailerons are mounted on the trailing edge of each wing near the
wingtips and move in opposite directions. When the pilot moves
the stick left, or turns the wheel counter-clockwise, the left aileron
goes up and the right aileron goes down. A raised aileron reduces
lift on that wing and a lowered one increases lift, so moving the
stick left causes the left wing to drop and the right wing to rise.
This causes the aircraft to roll to the left and begin to turn to the

(Avionics)
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left. Centering the stick returns the ailerons to neutral maintaining
the bank angle. The aircraft will continue to turn until opposite
aileron motion returns the bank angle to zero to fly straight.
o Elevator:
The elevator is a moveable part of the horizontal stabilizer, hinged
to the back of the fixed part of the horizontal tail. The elevators
move up and down together. When the pilot pulls the stick
backward, the elevators go up. Pushing the stick forward causes
the elevators to go down. Raised elevators push down on the tail
and cause the nose to pitch up. This makes the wings fly at a
higher angle of attack, which generates more lift and more drag.
Centering the stick returns the elevators to neutral and stops the
change of pitch.
o Rudder:
The rudder is the vertical component of the tail assembly. The
rear half of the vertical tail section is hinged, allowing it to angle
left or right. When you apply rudder, you redirect the aircraft's
nose either left or right. Applying left rudder yaws the nose to the
left, while applying right rudder veers the nose to the right. Note
that applying rudder also produces a very slight rolling
movement, which can be negated by pushing the stick in the
opposite direction.

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Secondary Control Surfaces:
o Spoiler:
On low drag aircraft such as sailplanes, spoilers are used to
disrupt airflow over the wing and greatly reduce lift. This allows
a glider pilot to lose altitude without gaining excessive airspeed.
Spoilers are sometimes called "lift dumpers". Spoilers that can
be used asymmetrically are called spoilerons and can affect an
aircraft's roll.
o Flaps:
Flaps are mounted on the trailing edge on the inboard section of
each wing (near the wing roots). They are deflected down to
increase the effective curvature of the wing. Flaps raise the
Maximum Lift Coefficient of the aircraft and therefore reduce its

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stalling speed. They are used during low speed, high angle of
attack flight including take-off and descent for landing.
o Slats:
Slats also known as leading edge devices, are extensions to the
front of a wing for lift augmentation, and are intended to reduce
the stalling speed by altering the airflow over the wing. Slats may
be fixed or retractable.
o Air Breaks:
Air brakes are used to increase drag. Spoilers might act as air
brakes, but are not pure air brakes as they also function as lift-
dumpers or in some cases as roll control surfaces. Air brakes are
usually surfaces that deflect outwards from the fuselage into the
airstream in order to increase form-drag. Their purpose is to slow
down the aircraft

(Avionics)
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Generators:
Most aircraft require some form of electrical power to operate
navigation-, taxi-, landing-, strobe lights, one or more COM and
NAV radio's, transponder, intercom and other electronic
systems. The electrical system consists of a battery and an
alternator or generator on aircraft.
 Vortex generator:
A vortex generator (VG) is an aerodynamic device, consisting of
a small vane usually attached to a lifting surface (or airfoil, such
as an aircraft wing) or a rotor blade of a wind turbine.
 APU (Auxiliary Power Unit):

(Avionics)
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An auxiliary power unit (APU) is a device on a vehicle that
provides energy for functions other than propulsion. They are
commonly found on large aircraft and naval ships as well as
some large land vehicles. Aircraft APUs generally produce 115 V
alternating current (AC) at 400 Hz (rather than 50/60 Hz in mains
supply), to run the electrical systems of the aircraft; others can
produce 28 V direct current (DC). APUs can provide power
through single- or three-phase systems.
 Batteries:
Batteries which we used in aircraft are of NiCad. NiCads are
based on a strong alkaline for their electrolyte. WE use it in the
case of emergency for landing if our generator does not works.
Communication:
There are two types of communication done which are as follows;
1. HF (High Frequency)
2. VHF (Very High Frequency)

(Avionics)
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 HF Communication:
High frequency (HF) is the ITU (International
Telecommunications Union) designation for the range of radio
frequency electromagnetic waves (radio waves) between (3 and
30 MHz). It have 28000 channels and channel spacing if of 1 KHz.
The HF band is a major part of the shortwave band of
frequencies, so communication at these frequencies is often
called shortwave radio. Because radio waves in this band can be
reflected back to Earth by the ionosphere layer in the
atmosphere – a method known as "sky wave" propagation. The
band is used by international shortwave broadcasting stations
(2.8 - 26.9 MHz).
 VHF Communication:
Very High Frequency Communication is the standard civil short
range communication facility. The range of radio frequency
electromagnetic waves (radio waves) from (30- 300 MHz)
using the band of frequencies between (118.000 – 136.9 MHz).
VHF is used by ground control facilities and aircraft or by aircraft
and other aircraft. Current International Civil Aviation

(Avionics)
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Organization (ICAO) regulations require a new channel spacing
one third of the current spacing i.e. 8.33 kHz. This will treble the
number of available channels to 2280. To calculate VHF range,
you may want to use this formula:
R=1.23√ 𝐻1 + 𝐻2
Where;
H1 = Height of Transmitter
H2 = Height of Receiver
Radar:
Radar is actually an acronym that stands for (Radio Detection
And Ranging). It was developed in the early 1940s. Radar
equipment emits a high energy radio signal from an antenna.
The signal travels out from the source until it is reflected back by
contact with an object. The radar antenna relays this signal to a
scope where the image is displayed. Using the time it takes for
the emitted signal to reach the object and reflect back to its
source, the distance to the object can be computed. The radar
signal is moving at the speed of light and can make such a trip in
microseconds. In aviation, a ground radar antenna sends radio
signal pulses into the sky. These signals are reflected back by

(Avionics)
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aircraft flying in the airspace. The radar scope displays the
direction and distance from which the signals are reflected back.
There are two types of radars which are as follows;
1. Primary Radar
2. Secondary Radar
 Primary Radar:
A Primary Radar transmits high-frequency signals toward the
targets. The transmitted pulses are reflected by the target and
then received by the same radar. The reflected energy or the
echoes are further processed to extract target information.
 Secondary Radar:

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Secondary radar units work with active answer signals. In
addition to primary radar, this type of radar uses a transponder
on the airborne target/object. The secondary radar unit
transmits and also receives high-frequency impulses, the so
called interrogation. This isn't simply reflected, but received by
the target by means of a transponder which receives and
processes. After this the target answers at another frequency.
Various kinds of information like, the identity of aircraft,
position of aircraft, etc. are interrogated using the secondary
radar. The type of information required defines the MODE of
the secondary radar.
Navigation:
A navigation system is a (usually electronic) system that aids in
navigation. They set the references which is said as True North.
It tells about the variation which is the angle between the true
north and magnetic north. Deviation is the error in compass of
north and true north. The ADF and VOR are the navigation and
the communication way. ADF transmit frequency between (102
- 1750 KHz), there are two antennas loop and sense antenna.
Loop antenna has a figure of 8 and sense antenna has the figure
of circle. VOR has the frequency between (108 – 118 MHz), it

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has 50KHz channel spacing and have 160 channels of VOR and
48 channels of localizer.
Line Maintenance
Instrumental Shop:
• We were posted to the Instrument Shop.
• There we learnt about the following devices.
• Oxygen Mask

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• INS is comprised of 3 parts.
1. Inertial Navigation Unit (INU)
2. Controller Display Unit (CDU)
3. Mode Selector Unit (MSU)
• There is also another system which is Inertial Reference
System and it is used in 737 and A310.
• It is also made up of 3 components.
1.Inertial Reference Unit (IRU)
2.Inertial System Display Unit (ISDU)
3.Mode Selector Unit (MSU)
• These two systems work as EYE of the aircraft.
• The main difference between INS and IRS is that IRS has
Flight Management Computer(FMC) separately.
• An air data computer (ADC) is an essential avionics
component found in modern glass cockpits.
• This computer, rather than individual instruments, can
determine the calibrated airspeed, Mach number, altitude,
and altitude trend data from an aircraft's pdot-static
system.
• In some very high speed aircraft such as the Space Shuttle,
equivalent airspeed is calculated instead of calibrated
airspeed.

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• An airspeed indicator, which indicates the speed at which
the plane is moving through the surrounding air.
• An altimeter, which indicates the altitude or height of the
plane above mean sea level.
• There are usually two types of altimeter used in modern
airplane.
1.Radio Altimeter (0 to 2500ft)
2.Barometer (2500ft and above)
• An attitude indicator, sometimes called an artificial
horizon, which indicates the exact orientation of the plane
about its pitch and roll axes.
• A vertical speed indicator, which shows the rate at which
the plane is climbing or descending.
• A turn coordinator, or turn and bank indicator which helps
the pilot maintain the plane in a coordinated attitude
while turning.
• A two-way radio to enable communications with other
planes and air traffic control. Planes built before World
War II may not have been equipped with a radio but they
are nearly essential now.
• Instruments showing the status of each engine in the
plane (operating speed, thrust, temperature, RPM, and
other variables).

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• Combined display systems such as primary flight displays
or navigation displays.
• Information displays such as on-board weather radar
displays.
• 1 knot mile= 1.15 mile.
• A magnetic compass aboard an aircraft displays the
current magnetic heading of the aircraft, i.e., the aircraft's
directional orientation relative to the Earth's geomagnetic
field, which has a roughly north-south orientation.
• The compass continues to operate despite failures in the
electrical, vacuum or pdot static systems.
• Dynamic pressure is created by Pneumatic pumps.
ELECTRIC SHOP:
we have to reported the electrical shop.
• They sends us to battery shop

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• Here we thoroughly studied about the battery and also
compare the aircrafts and normal battery used in cars and
Ups.
• Also discussed the advantages of nickel cadmium battery
over lead acid batteries
• We also see how the batteries are tested, and also the
charging method.
• We also study the deep cycling method.
• On the next day we visited different sections of Electrical
shop.
• We were then allocated to the Electric Shop.
• Mr. Sajjid told us about many electrical components that
were calibrated there.
• Calibration is actually comparison between the standard
and Unit Under Test.
• The items are sent to Islamabad for Calibration.
• The Electric component in SI unit is Ampere.
• So all the electrical quantities are measured with
reference to amperes.
Conclusion:

(Avionics)
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It was a great experience to get opportunity to do internship in
PIA, and by luck we got a good experience instructor which gave
us fully knowledge of Avionics, in our 15 day’s internship we get
chance to learn 7 days in wide body, and other 7 days in line
maintenance the duration was short but due to sincerity of our
instructors we almost get the fully knowledge about aircrafts and
what communications equipment’s we are using in cockpit or in
whole aircraft. we are basically the students of
telecommunication so we tried to focused on communications
equipment’s in the duration of internship almost we get a
chances to visit aircraft either it was on check A, B, C or D and also
we gone through the different workshops which are in hangar
area of PIA likewise, electrical, instrumental, iru, radio and
others.

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