2 Flashcards
1
Q
What are the tasks of an aircraft engine?
A
It supplies hydraulic power, electric power and bleed air for the pneumatic system. It also gives thrust.
2
Q
What are the disadvantages of piston engines
over gas turbine engines?
A
High to power ratio and performance loss in
high altitudes.
3
Q
How is propulsion force created?
A
By accelerating air pressure.
4
Q
Jet propulsion is also called?
A
Reaction engine
5
Q
What are the two ways of increasing the
pressure?
A
High pressure by compressor and volume of air when a fuel/air mixture is burned.
6
Q
How is thrust generated by turbofan engine?
A
Large mass of air with low velocity.
7
Q
How much thrust is generated by the secondary
airflow?
A
80%
8
Q
What is the formula for thrust?
A
Mass of air X velocity of air
9
Q
Which airflow produces the majority of the
thrust?
A
Secondary
10
Q
What is bypass ratio?
A
Secondary over the primary airflow.
11
Q
Exhaust Gas collide with ambient air?
A
Produce more noise.
12
Q
Thrust?
A
Mass of air and velocity of air.
13
Q
Turbo jet?
A
More velocity, less air. Low bypass engine.
14
Q
Thrust generated by turbofan?
A
Secondary and primary.
15
Q
Divergent?
A
Decrease in velocity, increase in static pressure
16
Q
Gearbox in turbo prop?
A
Manage the torque being given by the turbine.
17
Q
Modular?
A
modern aircraft engine. Is split into a set of separate major modules
18
Q
Cobalt base alloys are used for?
A
Stator of the 1st stage of HPT.
19
Q
Titanium base alloys are used for?
A
Mainly used in fan, the lpc and front stages the hpc.
20
Q
Nickel based alloys are used for?
A
Hpc, hpt, lpt.
21
Q
4 cycle of a gas turbine engine?
A
Induction, compression, combustion and expansion.
22
Q
How do you increase the energy?
A
combustion
23
Q
The static pressure in the combustion chamber is?
A
constant
24
Q
It supplies a continuous flow of air to the combustion chamber?
A
compressor
25
Compressor
increase in pressure and
temperature
26
Kinetic energy to mechanical torque?
turbine
27
It drives the AGB and compressors
turbine
28
Pressure relationship between two different areas?
pressure ratio.
29
Compressor discharge pressure over compressor inlet pressure
30
40 : 1
means that the discharge is 40
times the inlet.
31
Turbine pressure discharge over inlet pressure.
32
To increase the service life of an engine?
flat rating
33
Engine indicators of thrust?
rpm or n1, EPR, TPR.
34
To monitor air flow in engine pressure and temperature
airflow station designations
35
Service life of an engine can be increased if the exhaust gas temperatures are always
kept as low as possible.
36
During cold day
more dense and more
thrust.
37
Test bench / test cell
on the ground, thrust
force of an engine can be measured on test
bench.
38
Why is the engine air intake a diffuser?
Divergent, to increase static pressure of the
air.
39
Engine is running but aircraft is not moving?
Negative pressure, no ram air effect
40
Why is there a need to decrease air entering the
compressor?
- Minimize energy losses caused by temperature increases.
- Disturbs or reduce the airflow and increase the temp. of compressor
41
What is the purpose of the divergent engine air
intake?
Decrease the velocity, increase static pressure.
42
What air is used for anti-icing the engine?
Hot air directly from the engine of that particular engine.
43
What air is used for anti-icing the wing?
Hot air from pneumatic system, apu or engine
44
Can you switch anti-ice in one engine only?
Yes, it has individual switch per engine.
45
Can you switch wing anti-ice individually?
No because it operates symmetrically.
46
How many switches are there for wing anti-ice valve?
Only one
47
How many switches are there for engine anti-ice valve?
One for each engine. Independent anti-ice switch.
48
In what position can you lock the wing anti-ice valve?
In closed position only.
49
In what position can you lock the engine anti-ice valve?
In both open or closed position.
50
When will the fault light appear in the switches?
During transit and when there is a
disagreement of switch.
51
Subsonic speed needed by the engine.
52
What are the 5 main sections of a gas turbine engine?
Fan, compressor, turbine, combustion and
exhaust
53
What is the purpose of the compressor?
Continuous supply of air to the engine combustor.
54
What are the characteristics of air as it comes out of the compressor?
Constant velocity. Temperature and
pressure increases. Volume decreases.
55
What are the two types of compressor?
Centrifugal and Axial
56
What is the main advantage of axial compressor
over centrifugal compressor?
It produces higher pressure.
57
How do you define an axial compressor stage?
Rotor followed by a stator
58
What is the purpose of rotor blade?
Imparts velocity
59
What is the purpose of stator vane?
Transforms velocity(constant across the compressor) in pressure(increase)
60
What is a centrifugal compressor?
Consist of impeller and diffuser. Used on small turbine engines like APU's. Air is sucked horizontally.
61
A centrifugal compressor consists of?
Impeller and diffuser
62
What is the compressor ratio of an axial flow compressor?
1.3 : 1
63
What is the compressor ratio of a centrifugal flow compressor?
5 : 1
64
What is the most efficient centrifugal compressor?
2 stages only
65
Does double face impeller increase pressure?
No, it only gives higher airflow.
66
What is a compressor stall?
Separation of airflow
67
What is surge?
- Very severe form of compressor stall.
- Heavy vibrations and loud banging noises
68
What are the ways of preventing stall?
- Compressor bleed valves - bleed excess air in the engine. Open at low engine speeds.
- Dual or triple spool rotors -acceleration capability.
- Variable Vanes - optimum angle of attack
69
Where can you find the variable stator vanes?
In front/fwd of the HPC
70
Which kind of stall/surge is more serious?
Surge in the AFT stages of the compressor.
71
Where can you usually find variable inlet guide
vanes?
In front of the HPC
72
Is variable inlet guide vanes part of the compressor stage?
No
73
Streamline the airflow, mounted and bolted into the fan?
Spinner cone
74
What are the conditions that cause stall or surge in the engine ?
Dents or ice, damaged rotor blades, damaged or broken combustor, damaged
turbine components.
75
Compressor stall due to?
- Low speed - fed stages supply too much air
to the aft stages.
- Fast dec. - rotor speed of hpc decreases faster than lpc.
- Fast acceleration - leads to much fuel into the combustion.
76
What component produce majority of the thrust?
Fan
77
. Outlet guide vanes? Location?
They improve the airflow into the fan nozzle. Stator vanes located in the fan duct.
78
Inlet guide vane? Location?
Improve the airflow into the first compressor stage. Fixed or movable. It is located in front
of HPC.
79
Data location on blades?
Blade root. You can find P/N, S/N, moment weight.
80
Where is fan blades mounted?
81
Rotor blades
Suck in air and push it to the outlet side of the rotor. Increases in energy flow.
82
Stator vane
Guide and slow the airflow to cause an increase in pressure
83
Rotor is always the first part of a compressor stage.
84
Angle of attack on the rotor blades and stator vanes is small?
Airflow is smooth
85
. Stall
high egt.
86
Soft tip spinner cone
Cause small imbalance which prevents large ice build up
87
Used to balance the opposite blade?
Balance screws
88
Used to scare birds away and to know if the engine is rotating.
Spirals or white markings
89
The most critical area of a blade?
Blade root.
90
Mid span shroud?
- Additional strength and rigidity
.
- Use a special coating for sliding ops.
91
Do not have shrouds, they are more efficient than conventional blades, they can run at lower speed which reduces noise and they are very flexible. Can whistand FOD much better.
Wide chord fan blades
92
Shrouded fan blade
All the impact energy absorbed by the tip.
93
Help to stiffen the case and prevent deformation? Adds strength and rigidity. Used for
installing other components.
Flanges
94
Protection for the tip of the blade?
Abradable shrouds.
95
Reduce/absorb the noise created by the fan?
Acoustic panels.
96
Protect the engine/ fuselage when the fan blade
breaks?
Cowling
Note : Pylon - engine mount - fan frame
97
Struts
hollow
98
Blades are repairing is called
Fan blade blending
99
Moment weight = blade mass * distance
- Found in the root blade
- Old is crossed out if new moment weight is achieved after blade blending.
100
Process of welding the joint?
Inertia welding
101
VIGV
corrects the angle of attack to prevent
stall.
102
Compressor discharge pressure seal (CDP)?
Control the airflow/ minimize the leak.
103
Rotor attachment method
- Locking lug
- Retainer ring
104
What is used to inspect the engine ports?
Borescope Ports
105
Two zones of combustion chamber?
Dilution and primary zone.
106
Why do we have to slow down the air before
entering the combustion chamber?
To have a complete combustion inside the combustion chamber.
107
Used to reduce airflow?
Diffuser
108
Shape of diffuser?
Divergent
109
Coating used to protect excessive heat?
Ceramic coating
110
Flammable mixture requirements? Primary conditions for correct and safe combustion?
Correct ratio of fuel and air and air velocity must be slow enough inside the combustion
chamber.
111
types of combustion chamber?
- Can type
- Can annular
- Annular combustor
112
2 airflows in the combustion chamber?
- Primary airflow 20% to 30%
- Secondary airflow 70% to 80%
113
Primary is for what and how many percent? (In combustion)
20% to 30% for combustion.
114
Secondary is for what and how many percent?
(In combustion)
70% to 80% for cooling.
115
Dilution holes is for what?
Large
116
Film cooling holes?
o create a film preventing direct contact of the inner liner and the heat from the combustion chamber.
117
To produce a hot stream of gas for the turbines and for jet nozzle?
Combustion chamber
118
Ideal air to fuel ratio?
15 : 1
119
It accommodates the fuel nozzles and igniter plug?
Combustion case
120
Turbine stage
- HPT Stator/Nozzle guide vane - unang tatamaan ng hot air.
- HPT Rotor 2nd.
121
Igniter plug
- Lower part, because more parts of air is in the lowest part of the chamber.
- Can be used also as borescope hole.
122
To create turbulence for proper mixing of air:fuel?
Swirl vanes
123
Why do we need fixed and movable liner?
To have a thermal expansion allowance.
124
Turbine section is consist of?
Stator and rotor
125
Purpose of nozzle guide vane?
Direct the air to the rotor blades.
126
Purpose of the rotor vane in the rotor stage?
Kinetic into mechanical torque
127
Rotor blades in axial?
Fir tree
128
. Advantages of fir tree shape?
- Many contact surfaces advantage and the loads are transmitted gradually.
129
Why are turbine blades are susceptible to damage compared to compressor blades?
Because of high temperature.
130
Two main function of turbine?
It drives the compressor and accessory gearbox
131
What part of the high pressure turbine (hpt) has the highest heat to metal contact? First component that will be hit by hot gases from the combustion.
HPT nozzle guide vane (stator)
132
Two types of turbine blades?
Impulse and impulse-reaction/reaction
133
What is impulse?
- Impulse turbine relies more in the impact of the air in the blade
134
What is impulse reaction?
Accelerate by impulse and reaction
135
What is Creep?
Permanent deformation
136
3 factors of creep?
High temp., centrifugal force and time.
137
Purpose of the shroud in the turbine?
Reduce vibration
138
Why maximum egt should not exceed?
Can cause damage
139
N1?
Fan speed, LPC, LPT
140
N2?
Core speed, HPC, HPT
141
Turbine cooling
- Convection - easiest method hollow turbine nozzle vanes and rotor vanes
- Impingement - inserts with many holes.
- Film cooling - drilled cooling air holes.
142
Large tip clearance cause what?
More fuel consumption
143
Engine speed tip clearance
- Low STC - no much cf, only temp.
- High STC - due to high centrifugal force.
144
Clearance control system
- Active - regulated by vanes
- Passive - unregulated
145
Best speed tip clearance?
Optimum STC.
146
. Cooling tubes
- LPT cooling tubes - circular shaped, holes pointing directly to the turbine case
- HPT cooling tubes - rectangular shapes, bleed holes are at the edges, blows air to
the thickest layers/parts.
147
Solenoid valve
- Close or open only.
- Also called two position valves
148
FADEC
Full Authority Digital Engine Control
149
Interstage seal
minimize the leakage
150
It is designed to absorb the loads of the blade?
Stage disc
151
Turbine frame function
- First absorb the aft bearing loads
- 2nd is to provide attachment points for turbine frame/ rear engine mount.
152
Frame struts
- Radial - minimize expansion of struts and keeps stress on the frame hub low. But it
tends to crack.
- Tangential - minimize stress caused by thermal expansion. If they expand, they will cause the hub to rotate slightly.
153
Purpose of exhaust nozzle?
Accelerate the exhaust gases into the hub of the turbine rear stage.
154
Purpose of exhaust system in turbo prop?
To discharge safely the airflow overboard
155
Purpose of exhaust system in turbo fan?
To discharge safely the airflow overboard. And create 20 % of thrust from the primary
airflow.
156
Purpose of exhaust system in turbo jet?
Accelerate airflow and make thrust.
157
Interlock position? Thrust reverser interlock sys.
- It makes sure that the engine power can only be increased after the reverser is fully
deployed.
158
. If only one thrust reverser is not fully deploy, it
goes to reverse idle.
159
The reverser control system is always protected
by the air ground logic.
- Deploys only on ground
- Some a/c 10ft below can deploy.
- Must be manually selected on the cockpit
160
It prevents reverse flow of the exhaust gases into the hub of the turban rear stage? It guides the
discharge flow and prevents excessive turbulence
of gases.
Exhaust Cone
161
Exhaust nozzle
- Separate - primary and secondary airflow.
- Common - mixes hot and cold gas flow. Reduce high exhaust gas velocities and gives higher propulsion efficiency
162
It improves the mixing of the hot and cold gas
flow to get higher propulsion efficiency?
Exhaust gas mixer
163
It aerodynamically stop the aircraft during landing?
Thrust reverser and brakes
164
Type if thrust reversers:
- Bucket door
- Clamshell
- Cascade vanes
- Pivoting door
165
Stall is accompanied by high egt.
166
Ball / Fixed
axial and radial
167
Roller / floating
radial load and it supports thermal
expansion.
168
Direct lubrication
- oil is directly sprayed onto the bearings.
- bearings with low loads.
- more intense lubrication
169
Indirect / underace lubrication
- sprayed on the inner wall
- oil stays on wall due to centrifugal force
170
Carbon seal
- used in AGB and sumps in bearing compartments.
- prevent leakage of oil
171
Do we use brush seals?
No
172
Pressure balancing
reduces axial load
173
Mas malakas na axial load sa compressor?
forward direction.
174
Mas malakas na axial load sa turbine?
aft direction
175
Accessory drive system is used to power the electric and hydraulic system.
176
High pressure rotor
the rotor which is used to
turn the AGB
177
The diameter of the radial bevel gear is usually
smaller than the diameter of the horizontal.
178
Horizontal bevel gear
more teeth, rotates
slower than radial bevel gear.
179
Radial bevel gear
- less teeth, rotates faster
than horizontal bevel gear.
180
At a certain speed bibitaw yung starter using the
CLUTCH
181
During starting
HPC starts first, then followed
by ignition then fuel. Painitin muna using ignition then fuel.
182
In the AGB all the accessory units rotates and
interconnected to each using the
Gear Train /
Spar gear
183
Wind milling
can damage the bearings of your engine due to not enough oil is lubricating the
bearings.
184
1:1
1 revolution sa manual hand crank device
equals 1 revolution sa HP rotor.
185
Hand crank device
for maint.
186
Oil damped bearing
reduce dynamic loads. Oil
muna mag absorb ng load then the bearing.
187
Air seals / outer seals
minimizing air escaping
from the cavities
188
Oil seals / inner seals
prevent oil from
escaping from the bearing compartment.
189
Viscosity
Resistance to flow
190
Flash point
the lowest temperature at which it begins
to vaporize.
191
Flash point of oil?
high flashpoint
192
Flush point of fuel?
low flash point
193
Synthetic
recommended engine oil for gte.
194
3 purpose of oil in the engine?
Cleaning, cooling, lubrication.
195
It houses the bearing compartments?
Sump
196
What is dry sump?
Scavenge system and external tank
197
What are the basic lubrication subsystems?
- Vent
- Monitoring
- Scavenge
- Oil reservoir and supply
198
Under oil cooler:
What is used to cool in oil cooler?
Fuel
199
Also known as a heat exchanger?
Oil cooler
200
Which has the higher pressure ?
Fuel
201
Which is better: oil to contaminate the fuel? Or
fuel contaminate the oil?
Fuel to contaminate the oil
201
How will you know if your oil is contaminated with
fuel?
- If you smell fuel in the oil tank (fuel contamination)
- abnormal quantity of oil (laging uno or pabago-bago yung oil tank)
202
It can damage the heat exchanger or leak?
Mixed fuel and oil
203
What type of sump is the scavenge system?
Dry sump
204
Meaning of SOAP? And what particles it can
detect?
- Spectrometric Oil Analysis Program
- Small particles that cannot be caught by oil
filters. (0.001 to 0.02 mm)
205
Consist of 2 magnet?
Electronically Monitored Magnetic chip
detector
206
What will happen if the gap between two magnet is filled with metal?
- The resistance between the 2 magnets gets below its limit and sends a maint. message
for the PFR. (MAGNETIC CHIP
DETECTED)
- This completes the circuit. There is a chip
detection
207
Why low pressure pump is needed?
To prevent cavitation going to the high pressure pump
208
Oil temperature sensor
Thermocouple - hot areas. Return and scavenge lines.
- Thermistor - supply lines. Warm areas.
209
Lube analysis
If there's an engine deterioration
210
When you identify the material…
You can identify the engine part with wear.
211
Scavenge oil filter
- 0.015 mm particles
212
Magnetic chip detectors
- Manual - removed manually to check for chips.
- Electronic - electronically monitored. Only
one, called main/master.
213
Wait for 5-20 min.
214
Anti-Siphon which stop the flow of oil during
shutdown.
215
A wrong detector installation can lead to a leak
in the oil system and in-flight shutdown of the
engine.
216
Fuel is used for?
- Combustion
- Servo fuel/muscle pressure
217
Where is the main fuel flow?
Combustion
218
What is fuel heater? And what it is used to heat
the fuel?
- Heat the fuel
- Oil is used to heat the fuel
219
Can FCU can control the engine it self?
Yes it can.
220
Two major sections of FCU?
- Fuel metering section - make sure that necessary fuel gets to the fuel nozzles and
all the fuel, which is not needed for combustion returns to the fuel pump
- Computing section - governing and limiting
section. Limiting is for protection, governing
is for N2.
221
It meters the fuel that is needed for combustion.
It is also responsible for supply and shut off of fuel
to the fuel nozzles at the combustion chamber
Fuel control unit
222
It measures the actual fuel flow and transmit
signals to the cockpit for fuel flow and fuel used
indicator.
Fuel flow transmitter
223
To have a better spray saturation of the nozzle?
- High pressure compressor
- 900psi
224
Over- pressure relief valve?
- To prevent damage
- 1250psi
225
It only opens when the fuel is too hot?
- Fuel recirculation valve
- Fuel goes back to the tank or cooling of idg
or engine oil.
226
It can control engine speed and fuel servo
system?
FCU
227
FCU signals uses
- Hydraulic signals
- Mechanical signals
- Pneumatic signals
228
A digital computer as a full authority over the
engine control functions?
FADEC
229
t talks about cooling, clearance control and
compressor control?
AIR SYSTEM
230
Compressor control?
IN HP AND LP (the
variable bleed valves).
231
During engine shutdown the VIGV and VSV
is medyo close, it allows the smallest
possible angle of attack because your
engine needs less air going shutdown.
232
During shutdown, HPC slows down
because less air is needed at the same time
the VBV is open.
233
At designed speed, VBV is close. VBV is
open to prevent stall and pag shutdown and
starting.
234
HPC bleed valves
in mid-point or bandang
last stage. To bleed excess air.
235
Clearance control?
UN HPT AND LPT,
SOMETIMES COMPRESSOR
236
What kind of air is used in the HPC rotor? -
HOT AIR or WARM AIR.
237
What kind of air is used in the turbine case?
cold air
238
It improves the efficiency of the engine?
CLEARANCE CONTROL
239
The purpose of external cooling system
aside form cooling?
FOR VENTILATION
OF THE CORE, TO PREVENT
ACCUMULATION OF FUMES AND
GASES. IT ALSO VENTILATE LEAKS
240
What is used to cool the fan compartment?
ram air
241
What is used to cool the core
compartments?
fan air
242
What is more pressurized? The fan or core
compartment?
the fan air, to prevent the
propagation of fire coming from the core.
243
The air called after the low pressure
compressor
the lpc discharge or the hpc
inlet air
244
Components of ignition?
lead, exciter,
starter.
245
Starter/starting system consist of
starter
duct, starter motor and starter shut-off
valve.
246
There are two INDEPENDENT ignition
system.
247
One independent is always powered by
EMERGENCY BUS
- it’s a NO-GO item.
248
The other one is normal powered.
249
Starter supply duct
connects the
pneumatic system and the starter motor.
250
Sources of air for starting?
APU, the other
engine, or GPU.
251
Time at starter can be used continuously?
Time at starter can be used continuously? -
Duty Time (2mins)
252
Indicates a successful start?
EGT indicates.
253
Two types of starter?
pneumatic and
electric.
254
Pneumatic starter
for engine, (may turbine)
255
Electric starter
for APU (walang turbine)
256
Starter has HI TORQUE, LOW SPEED.
257
Common to both electric and pneumatic
starter?
starter clutch
258
Starter shut-off valve?
spring loaded
closed so the solenoid is used to energize
the valve to open
259
Cooling for starters?
oil is used
260
Starter check for oil level and for chip
detection. Check for contamination and
deterioration.
261
Fwd. thrust lever
informs the FCU on how
much thrust is requested.
262
Starter lever
switch the fuel on and off.
263
It is used to transform mechanical input to
electrical signals
resolver
264
Control lever has two seperate switch
signals.
265
Thrust reverser / reverse lever lock system
prevents simultaneously movement
between reverse thrust and fwd. thrust
266
Continuous ignition
pag nag flame-out or
icy conditions.
267
Start ignition
one time only pag
combustion, tapos off na.
268
ECU
ignition system. Spark and ignite the
fuel: air mixture in the combustion system.
269
Ignition system
ignition exciter, igniter
plug, ignition leads and electrical power
supply and switches
270
DC high voltage ang labas.
271
Ignition lead sa
core area may cooling, sa
fan area wala masyado kasi medyo
malamig na dun.
272
Immersion test
pag nagalaw mo lang yung
bushing pero pag remove and replace lng
ng plug no need test.
273
Ceramic igniter plug
must not drop
274
Ignition exciter
may low voltage (1
spark/sec.) and high voltage (2 spark/sec.)
275
ignition lead cooling
fan air or booster air.
276
Pag nasa self-sustaining speed na di pa rin
bibitaw ang clutch until maabot nya yung
starter cut-out speed. (N2)
277
EPR
has an inlet pressure switch and
turbine discharge pressure switch.
278
If one thermocouple probes is damage or
loss
may indication pa rin pero it's less accurate.
279
EPR
indicates or measure thrust using
pressure.
280
Thermocouple is made up of chromel and
alumel.
281
Fuel flow transmitter
fuel flow and fuel
used. 2nd law of motion.
282
Tachometers
units in RPM, used to
measure thrust by rotation
283
Engine trend monitoring
To prevent larger
performance reductions or even engine
problems during flight. Monitoring tool that
alerts us to a problem at an early stage
284
EPR corresponds to engine thrust?
yes
285
Vibration increases
deterioration in engine.
286
Vibration sensors
sense radial
measurement direction.
287
Vibration sensor in HPR
distance of
vibration
288
Vibration sensor in LPR
bilis ng vibration.
289
Oil pressure indication and low pressure
indication
senses the press. diff. between
the total oil pressure in OIL SUPPLY LINE
and the VENT pressure in the oil tank.
290
SOAP
can find small particles that the
magnetic chip detector or oil filter can't
detect.
291
Methods of power augmentation?
water or
water-methanol injection and after burners.
292
Water methanol injection
increase the
density of air, and higher thrust. Applied in
combustion inlet, compressor inlet, engine
inlet.
293
Water injection
decreases the temperature
in the combustion chamber so that you can
add fuel. It results in increase of volume
gases
294
Ordinary water is not used because of its
high mineral content that could cause
deposits sa turbine.
295
Methanol
to prevent icing, less freezing
point than water.
296
After burner fuel is introduced in the LPT.
50% of thrust
297
Exhaust of afterburner is variable.
298
Catalytic ignition, spark ignition, hot shot
ignition
methods of ignition.
299
Afterburning
also called Augmenting
300
Variable exhaust nozzle
must be larger
when used.
301
Turbo-shaft
a gas turbine energy, has
energy to shaft energy
302
Turbo-prop
is a turbo-shaft
303
APU
turbo-shaft
304
Turbo-shaft
not a turbo-prop.
305
Turbo-shaft
almost all of the power is in
the shaft.
306
APU
is a turbo-shaft. Turbine power to
pneumatic and electric.
307
Turbo-shaft is efficient than turbo-jet.
308
1st action when propeller speed increases
always move the blades into a more coarse
position.
309
2nd option is to reduce the fuel flow.
310
90%
turbo-prop generated thrust
311
Turbo-prop exhaust
static pressure and
temperature decrease.
312
Twin levers found in the turbo-prop?
condition lever and engine lever
313
Alpha mode
engine power controlled by
engine lever and propeller is controlled by
condition lever
314
Beta mode
engine power controlled by
condition lever and propeller is controlled by
power lever.
315
Propeller speed
condition lever
316
Fast rotation speed and small angle results
in
slow aircraft speed.
317
Shaft power engines
turboprop and
turboshaft
318
TPE
almost always an axial reaction type
turbine
319
TPE
free turbine connected to the
reduction gearbox.
320
Propeller
is connected to the reduction
gearbox.
321
Reverse flow combustion
reduce the
length
322
It reduces the shaft speed
reduction
gearbox.
323
Optimal rpm of the propeller is 850 to 2500
324
Adjustment areas of propeller blades
high
pitch, low pitch, feather position and
reverse.
325
High pitch
high airspeed
326
Low pitch
low airspeed
327
Feather position - for emergency and
for emergency and
328
Flight idle is higher than ground idle.
329
Free turbine connected to the reduction gearbox and from the RGB to the propeller.
330
How is one engine prevented from driving
the other engine in helicopter?
Free wheel
331
To allow the engine to drive the
transmission and prevent the rotor from
driving the engine.
free wheel
332
Transmission
direction of movement,
torque, force and speeds can be changed
using gears.
333
It provides elec. and pneumatic?
APU
334
APU can be used in flight?
YES, when
IDG fair or engine tapos need mo more
pneumatic and electricity, mag susupport
sya.
335
what is the speed of the APU after starting?
CONSTANT
336
It controls the constant speed of the APU
APU control unit
337
Opening of APU inlet door?
manually and
electrically
338
Can you automatic start the APU ?
No,
only manually by switches sa overhead
panel sa cockpit
339
Purpose of load compressor ?
Provide
bleed air pneumatic to the user
340
Compressor of the APU do what?
provide
air for cooling and combustion
341
It opens the apu fuel pump and apu shut off
valve near the APU ?
APU fuel line vent
push button. It is also used for maintenance
para di kana pumunta cockpit.
342
2 main diff. Of engine oil system and apu oil
system?
APU has a de-oiler valve and yung oil ng apu ginagamit mismo ng generator
nya compared sa engine oil system yung oil
ng generator nya (idg) is separated.
343
Apu oil is cooled?
through an air/oil heat
exchanger. (Air is used to cool the oil)
344
3 main sections of APU?
AGB, bleed
suction and power section.
345
A separate compressor called load
compressor. May variable inlet guide vanes
siya. Meaning can be closed, in between,
and open.
346
Iikot parin ba yung load compressor kahit
nakasara yung VIGV ?
Yes because
connected sya sa turbine shaft.
347
Load compressor
very fuel efficient, low
egt
348
APU PRESSURE
30 to 45 psi
349
Apu does not have a constant speed drive
ang nag cocontrol ng constant speed nya is
APU FUEL CONTROL UNIT
350
Pre-start test
makes sure that cpu control
unit itself operates properly and sensor
signals are available
351
If restart test is ok
normal, automatic, apu
fire switch
352
Manual
using master switch, safe
shutdown. Cool down of 120s
353
Automatic
due to defective components.
Oil pressure, high egt, high temp. No cool
down
354
Apu fire switch
sa cockpit. Meron din sa
nose landing gear, main wheel well ay
refueling station
355
Apu fuel pump is on if not enough yung
pressure na galing sa boost pumps ng fuel
tank. To prevent also cavitation
356
Primary fuel system of the apu
low
pressure fuel system. Fuel tank to apu fuel
control unit.
357
Secondary fuel system of the apu
high
pressure fuel system. FCU apu papunta sa
nozzles.
358
Apu air system
bleed air and cooling air
system
359
Anti-surge valve
normally open during
flight. Not very efficient
360
Surge control valve
sa may load
compressor. More efficient
361
De-oiling valve? -
362
Apu master switch
supplies electrical
power to the apu control unit which starts its
pre-test.
363
Apu does not have starter shut off valve.
364
Common sa engine at apu ?
Starter clutch
365
Starter duty time
time when apu can be
used
366
Starter cool down time
time to be cooled
367
Starter duty cycle
on/off, on/off, on/off
cycle
368
Ignition lead ng apu
walang cooling
369
Class 1?
most critical parts like the air inlet cowl. Only small dents are allowed.
370
Class 2?
fan cowling
371
Opening of cowling should be in sequence because diff. Cowling overlap each other.
372
For example : fan cowl must be open first before you can open the core cowling.
373
Air inlet cowling is cannot be split.
374
Two index pins
this makes sure that the air
inlet cowl can only be installed in the correct
position.
375
2 hold positions
fully open ( access to all
components) and half closed/open
(gearbox)
376
fan cowl open when engine is in ground idle
is allowed. Fan reverse cowl
release the
latch then use hydraulic to open.
377
Cowl load sharing
uses v - shaped grooves
and blades.
378
2 passive fire protection of fan thrust reverse cowling - fire protective coating (for
inner side of the cowl) and fire seal (on the connection to the fan frame)
fire protective coating (for
inner side of the cowl) and fire seal (on the connection to the fan frame)
379
parking and mooring
close all holes on the
engine
380
Forward mount
bolted to the fan frame
381
Aft mount
bolted to the turbine frame
382
Aft mount
Y,Z load or the vertical(weight)
and side loads.
383
Aft load has no axial mount load
to allow
thermal expansion.
384
Bootstrap (most common), crane method
(30% faster than bootstrap), uplift method
(40% faster)
385
drain mast is made of frangible material
para sya lang yung masisira incase na
tumama.
386
Fuel overboard drain
found on pylon
387
Collector
can't be emptied, if it is full the
fluid goes to the holding tank
388
Holding tank
can be emptied
389
Before you open the cowls
slats must be
retracted
390
In a fire protection system what happens
when you operate fire handle
generator
switched off, bleed air valve closes, shut-off
valve closes, hydraulic valve closes and
FIRE CIRCUIT engages.
391
Squib light is found in the AGENT push
button.
392
What will illuminate when the FIRE
CIRCUIT engage or activates ?
- SQUIB LIGHT.
393
If the bottle is empty
DISCHARGE light
illuminates.
394
If fire warning is still on after 30 s, must
discharge the second bottle.
395
What do you mean by 2 shots
can apply
two bottles in 1 engine.
396
Halon
used in engine fire
397
What will trigger the fire bottle ? Or the switch to trigger the fire bottle ?
AGENT
FIRE PUSHBUTTON
398
Local warning
RED LIGHT inside the
switch. The red light near the engine master
switch SHOWS the pilot what engine must
be shut down.
399
Central warning
aural, visual and warning
message on exam or eicas.
400
Dual cont. loop
engine fire detection
system
401
Hot start ?
high egt
402
Most common error when handling
magnetic chip detectors?
O-ring installation (they forgot to put O-ring)
403
What is blending?
repairing of blade
404
Borescope ports?
To view the internal parts
of the engine. INSTALLED IN BETWEEN
STATOR VANES
405
High egt
can be also compressor damage
406
Pag maagang nag disengage yung start
valve, fuel metering is wrong, duct pressure
is too low
HUNG START
407
When rotor cranking N1-by hand through
fan, n2 by hand cranking device through the
accessory gearbox.
408
Auto start steps :
409
Auto start
FADEC system computer
controls the whole start system. This
computer is the ECU
410
Auto start
step 1: engine mode selector
switch to IGN / START. Check pressure, oil,
engine start page.
411
Auto start
check for minimum duct
pressure of 25psi
412
Auto start
step 2: engine master switch on
(low pressure valve open and flows to the
HMU, starter valve will open)
413
Auto start
check n2 at 16% ecu activates
ignition
414
Auto start
check n2 at 22% ecu send
signal to hmu to open the metering valve
415
Fuel pressure opens the fuel shut off valve
and fuel flows to the spray nozzle.
416
Increasing EGT
successful start
417
Engine will accelerate on the thrust lever
position. Kaya dapat naka ground idle lang.
418
When n2 passes the starter cut out speed,
ecu send signal to color the starter valve
and deactivates the ignition
419
Engine master switched off
close signal is
sent to fuel shut off valve and fuel low
pressure valve
420
Engine spools down
421
Manual :
422
Manual step 1
ign/start mode
423
2:
engine manual start push button
424
3:
master switch on
425
In the manual start both ignition is on, in
auto only 1 ignition.
426
Engine Motoring
for engine leaks and sys.
checks. Starter motor is used
427
Wet motoring is always followed by dry
motoring.
428
Wet start
normal operation, fuel is sprayed
into the combustion chamber but engine
does not light up. (Due to ignition
malfunction). Dry motoring is need to
remove fuel
429
Engine stall
fuel metering is wrong, bleed
valve stuck close, degraded compressor
performance. ( also egt indication
fluctuates) ------patukan to ni sir.
430
First indication of a hot start?
egt is higher
than max allowable start value.
431
Hot start causes
maybe fuel metering is
wrong or remaining fuel from wet start isn't
blown out.
432
Nick is more serious than dent
433
Ways to inspect an engine
borescope,
trend monitoring, lube analysis and vibration
analysis.
434
Preservation of engine
to protect against
elements like dirt, corrosion, FOD and etc.
435
Desiccants
436
If more than 30 days
more comprehensive
preservation is needed.
437
Operable
can be started
438
