2. Introduction:
Pakistan InternationalAirlines is the flag carrier airline of the Islamic Republic of
Pakistan. Its main hub is Karachiwhile Lahore and Islamabad serveas secondary
hubs. PIA is one of the largest airlines in Asia operating services to 24 domestic
destinations and 39 international destinations in 25 countries. PIA is owned by the
Governmentof Pakistan (87 %) and the rest is by shareholders.PIA employed
nearly 14,000 peopleas of annualreport 2015 and the airline has an overall
punctuality of 88%.
Brief History:
Pakistan InternationalAirline Corporation was formed on 11 March 1955 as a
result of a merger between a proposed National airline and an already existing
airline named OrientAirways. OrientAirways was formed on the 23 October 1946
at the request of Quaid e Azam Muhammad Ali Jinnah to the IndustrialistMirza
Ahmed Ispahanito develop a flag carrier for the new nation. Itstarted its
operations in Calcutta but moved operations after independence to Karachi. In
1955 the newly formed PIA opened its firstinternational servicefromKarachi to
London using three newly acquired Lockheed L-1049CSuper Constellations.
PIA’s Lockheed L-1049C Super Constellation
3. Achievements
PIA has been responsiblefor many historic milestones someof which are stated
below
In March 1960 PIA leased a Boeing 707 becoming the second airline in all of
Asia to induct a jet aircraft in its fleet.
In 1962 Captain Abdullah Baig flying fromLondon to Karachiestablished a
world record for the speed over a commercial airline servicefor powered
landplanes of 938.78 km/h, a record which still holds today.
On 29th April, 1964, with a Boeing 720B, PIA earned the distinction of
becoming the first airline from a non-communistcountry to fly into the
People’s Republic of China.
In mid 1980s PIA helped establish Emirates by leasing two of its aircrafts an
Airbus A300 and a Boeing 737-300.
In 1990 FirstOfficer Maliha Sami became the first female pilot of PIA.
PIA also owns The Roosevelt Hotel in New York City.
The Roosevelt Hotel in New York City
5. PIA FLEET:
Aircraft Total Orders Engine
AirbusA310-300 5 0 CF6-XX
AirbusA320-200 11 2 PW
AirbusA330-300 0 4 Rolls-Royce
ATR 42-500 6 0 PW-127 E/M
ATR 72-500 5 0 PW-127 F/M
Boeing777-200ER 6 0 GE90-94B
Boeing777-200LR 2 0 GE90-110B
Boeing777-300ER 3 5 GE90-115B
Total 38 11
STEPS FOR MAINTAINANCE OF AN AIRCRAFT ENGINE
The following steps are generally followed by PIA for aircraftengines.
1. Removal fromaircraft
2. Disassembly of engine
3. Cleaning of engine and its differentcompartments
4. Non DestructiveTesting of different components
5. View of the engine for quality check
6. Assembly of the engine
7. Installation of engine at QEC
8. Test cell for testing of different parameters
9. Installation of the engine back to the aircraft
6. ENGINE DESCRIPTIONS:
All the engines used in PIA fleet are gas turbine engines which havea similar
working principalwith only difference in the stages of modules. For example, the
CF6-80C2 enginehas 14 stages of HP compressor whereas a PW127 has only 1
stage centrifugal HP compressor and the GE90 engines have 10 stages for the
same compressor. Following arethe different modules that are generally present
in a gas turbine engine:
7. Fan Module:
The ducted fan performs the firstpart of the Brayton Cycle which is the air intake
(or the suck partof the cycle). The fan case (the outside of the fan) and the fan
blades are made fromcomposite materials which are very strong and lightweight.
The blades themselves areshaped aerodynamically so as to pull air into the
engine as opposed to blowing it out when the fan rotates. This air intake by fan is
responsibleof providing between 70-80% of thetotal thrustrequired.
Compressor Module:
Once the intake air moves through the fan, it moves to the second engine
module: the compressor. Thecompressor, naturally, performs theair
compression or squeezepart of the Brayton Cycle. In order to produce the most
thrustpossible, the gas that enters the combustor mustbe condensed until it is
under a very high pressurebecausegas under pressureignites much more
violently and produces much more energy than gas at atmospheric (or normal)
pressure.
8. Combustion Chamber:
After the air is compressed to 10 times the pressureof the atmosphere, it is
ignited in the combustor to complete the bang portion of the Brayton Cycle. The
combustor is basically a large metal chamber equipped with radially placed fuel
injection nozzles and an electrically powered spark plug. The combustion chamber
is equipped with small holes cut into the metal of the combustor module where
the fuel nozzles will inject fuel into the center chamber of the combustor.
Turbine Module:
Even though the turbine is located between the combustion and exhaust
processes, theturbine actually uses some of the energy produced by the
combustor to drivethe fan and compressor. Theinitial startup of engine rotation
is provided by a gas powered motor, but the engine actually maintains its ability
to rotate through the power generated by its own combustion process. The
9. turbine is connected by a shaftin the center of the engine core through the
combustor to both the fan and compressor. Oncegas is rapidly forced into the
turbine module, the turbine begins to rotate at an extremely high speed, which, in
turn, forces both the fan and compressor to rotate an extremely high speed, as
well. With the fan and compressor rotating, the intake and compression
processes operatecontinuously and maintain the flow of the Cycle.
Exhaust:
The final module of the turbofan engine is the exhaust nozzlewherethe blow
portion of the Brayton Cycle takes place. When the combustor forces hot gas into
the turbine and the turbine further accelerates that gas backward, a large amount
of energy builds up at the exhaust. As the goal of any jet engine is to producea
large thrust, it is crucial to put this energy to use. While the nozzleof a turbofan
neither utilizes moving parts nor produces additional engine thrust, it provides
the crucialrole of directing the hot, high speed gases in the exact opposite
direction of aircraftflight, forcing the aircraftto moveforward
10. QUICK ENGINE CHANGEUP (QEC)
This is the section where PIA is able to physically test aircraftengines by
performing different experiments and monitoring various variables.
Some of the engines that the QEC tests are
1. CF6-80C2 for A-310
2. CF6-50 for B-747
3. CF M-56 for B- 737
Some of the parameters or variables that the QEC monitors are
1. EGT or ExhaustGas Temperatures
2. Pressure
3. Engine RPM
4. Thrust
Thisis where the engine ismountedandwiththe helpof
Differentsensorsabove mentionedvariablesare tested.
11. REPAIR SECTION
There are three types of repairing techniques used for repair.
1. Plasma Spray.
2. Electro plating.
3. Welding
1. Plasma spray
Plasma spray is the mostversatile of the thermal spray processes. This can be
applied to all materials that are considered spray able.
In plasma spray devices, an arc is formed between two electrodes in a plasma
forming gas, which usually consists of either argon/hydrogen or argon/helium. As
the plasma gas is heated by the arc, it expands and is accelerated through a
shaped nozzle, creating velocities up to MACH 2. Temperatures in the arc zone
approach 36,000°F (20,000°K). Temperatures in the plasma jet are still 18,000°F
(10,000°K) severalcentimeters formthe exit of the nozzle.
12. 2. Electro plating process.
Electroplating is a process that uses electric current to reduce dissolved
metal cations so that they form a coherent metal coating on an electrode.
The cations associatewith the anions in the solution. These cations are
reduced at the cathode to deposit in the metallic, zero valence state. For
example, in an acid solution, copper is oxidized at the anodeto Cu2+
by
losing two electrons. The Cu2+
associates with the anion SO4
2−
in the
solution to formcopper sulfate. At the cathode, the Cu2+
is reduced to
metallic copper by gaining two electrons. The resultis the effective transfer
of copper fromthe anode sourceto a plate covering the cathode.
13. 3. Welding process
Welding is a fabrication process thatjoins materials usually metals by
causing fusion which is distinct from lower Temperature metal joining
techniques such as soldering, which do not melt the base metal. There are
many kinds of welding we will only discuss onetype here i.e Arc Welding.
Arc Welding is a type of welding that uses a power supply to create an
electric arc between an electrode and the basematerial to melt the metals
at the welding point.
Welding of aircraftengine components has been taking place for many
years, buta number of developments - including arc welding productivity
and quality, fiber laser welding efficiency and and laser additive
manufacturequality - have led to exciting opportunities for the
manufactureof component
14. CHECK ON AN AIRCRAFT
There are different sorts of checks that become mandatory for an aircraft
after specific flying hours or cycles for maintenance.
There are three major checks that dues on respective flying hours.
1. Check A
2. Check C
3. Check D
Every aircrafthas differentschedule for different checks. This reportdeals
exclusively with the Boeing 777.
Check A
This is basically a minor check.
After 1000 flying hours or 75 days which ever comes firstcheck A will be
due.
Ittakes normally 2-3 days for its execution.
Check C
This is a major check.
After 10,000 flying hours or 750 days which ever comefirst check C will
become due.
Ittakes normally 15-20 days for execution.
Check D
Itis also a major check.
After four consecutiveCheck C, Check D will be due.
In this check different diagnostic operations are performed such as crack
check, air frame check etc.
Ittakes 35-40 days for execution.
