Engine Flashcards
1
Q
Draw the Engine System
A
See Study Guide
2
Q
What specific engine do we have?
A
GE CF34-8E5
3
Q
What type of engine do we have?
A
Hi-bypass, dual-rotor turbofan (2-spool), axial-flow
4
Q
What are the 4 engine stages?
A
Intake, Compression, Ignition, Exhaust
5
Q
Describe the N2 spool.
A
10-stage compressor with variable geometry, 2-stage HP turbine
6
Q
Describe the N1 Spool.
A
Single-stage fan, 4-stage LP turbine
7
Q
What is the engine’s max thrust?
A
14,200 lbs single engine, or 13,000 with both engines
8
Q
Draw the engine
A
See notes
9
Q
Draw the engine fuel system
A
see study guide or systems manual
10
Q
Which parts have lubrication systems?
A
Each engine, IDG?, and the APU have their own independent systems
11
Q
Starting and Ignition System Components
A
ATS (Air Turbine Starter), 2 igniters per engine, starter control valve, each engine can be started by APU air, crossbleed air, external air source, or windmilling start
12
Q
What is the normal engine start sequence?
A
FADEC controlled, for air starts the FADEC ignores the OFF position selected on the ignition NORMAL SEQUENCE: N2 rotation - 7% N2=Ignition, 20% N2=fuel flow (light off within 5sec), Normal acceleration and oil pressure, 50%N2=ignition off and starter cut-out, normal acceleration and stabilization
13
Q
Describe the thrust reverser system
A
hydraulically actuated, FADEC provides interlock protection against inadvertent deployment, Idle thrust commanded if opened in flight, for ground use only, idle thrust reverse is commanded while cowls are not totally deployed
14
Q
Describe the engine FADEC
A
ESS powered below 50%N2, PMA powered above 50%N2, 1 for each engine, each FADEC has 2 channels - one active and one standby
15
Q
Describe the ATTCS Automatic Takeoff Thrust Control System
A
Controlled by the FADEC, automatically provides max engine thrust (RSV) whenever it’s armed, thrust levers TOGA, and one of the following occur: difference between N1 and N2 values greater than 15%, one engine failure during takeoff, one engine failure during go-around, windshear detection (automatically armed for normal go-around mode)
16
Q
Describe FLEX takeoff
A
Reduced thrust for takeoff based on an assumed temperature
17
Q
Describe N1 indications on EICAS
A
Target N1 = cyan tick (max N1 for selected engine thrust mode), Rating N1 = green tick (max N1 allowed for current thrust rating and current operating conditions, Request N1 = moving arc (value requested based on TLA (Thrust Lever Angle))
18
Q
What are the different thrust rating settings available?
A
TO-1 (Takeoff) (10min max), TO-1 RSV (Takeoff Reserve) (10min max), GA (10min max), GA-RSV (10min max), CON (Max Continuous Thrust), CLB (Max Climb Thrust), CRZ (max cruise), Idle
19
Q
How is the engine protected during start?
A
The FADEC will prevent a hung start (inhibited in flight) where the compressor is not accelerating to generate required airflow, prevent a hot start (inhibited in flight) where insufficient airflow to keep ITT under control, prevent a no light-off where air and fuel but no ignition
20
Q
What happens if the engine overspeeds?
A
If N2 reaches 102%, the FADEC commands an automatic shutdown, in the event of 3 consecutive shutdowns due to an overspeed within 30 seconds, the FADEC will not attempt a relight
21
Q
What happens if the engine is over temperature?
A
The FADEC will prevent fuel flow during ground start until ITT is at or below 120 deg C, automatically dry-motoring occurs and fuel flow is commanded with ITT below 120 deg C
22
Q
What types of engines are on the aircraft?
A
2 general electric CF34-8E5 engines that are high-bypass, 2-spool, axial-flow, turbo-fan engines
23
Q
How much thrust do the engines produce?
A
13,000-14,200 lbs (ISA)
24
Q
Describe N1 spool
A
single-stage fan, 4-stage LP turbine
25
Describe N2 Spool
10-stage compressor (gas generator), 2-stage HP turbine
26
How many igniters are there per engine?
2
27
How many igniters activate for engine start?
Ground = 1 igniter (switch in AUTO), Flight = 2 igniters (switch in AUTO)
28
What happens when the ignition switch is selected to OVRD?
Activates both igniters on the ground or in flight
29
Can the igniters be turned off during flight?
The switch may be moved to the OFF position but the FADEC disregards the command, the OFF position is used for dry motoring on the ground only
30
What controls the engine?
a 2 channel FADEC, one channel is active and the other is in standby as a backup
31
Is only one FADEC channel used every flight?
No. They automatically alternate with each engine start
32
What does the cyan line on the N1 gauge represent during approach? When does it appear?
The minimum N1 for bleed requirements in icing conditions, configured for landing less than 1,200’ RA (when anti-ice is ON)
33
What sources are available for engine starting?
APU, Ground Source (air cart or air bottle), opposite engine (crossfeed start), windmill start
34
Does the FADEC provide engine start protection?
only on the ground for hot and hung start, also no light-off in air and on the ground?
35
What will the FADEC automatically do in case of a start on the the ground?
FADEC will not allow FF Fuel Flow if ITT is greater than 120 deg C, FADEC will automatically dry motor engine and introduce fuel with ITT is less than 120 deg C
36
Describe the engine start sequence
Start switch momentarily to START, 7%N2 Ignition, 20%N2 Fuel Flow, 20%N2 + 5sec Light-Off, 50%N2 Ignition Off, 50%N2 Starter Cutout
37
The engine stabilizes when:
N1=27%, ITT=460deg C, N2=62%, FF=550lbs/hr, Oil pressure is greater than 25 psi
38
What does WML mean on the engine indications?
Windmilling engine, the FADEC has detected a flame-out and is attempting an auto re-light or an assisted start has been commanded
39
What provides underspeed and overspeed protection?
The FADEC via the FMU, approximately 52%N2 and 102%N2 respectively
40
What happens after 3 overspeed detection events?
FADEC will not re-light the engine
41
What heats the fuel and cools the engine oil?
Fuel/heat exchanger
42
What is ATTCS? What controls it?
Automatic takeoff thrust control system, it is controlled by the FADEC, it provides max thrust reserve (RSV) according to current rate previously selected via the MCDU
43
What will trigger an ATTCS event?
N1 difference greater than 15% between engines, engine failure during TOGA, windshear detection
44
When is thrust reverse available?
Weight-on-wheels (ground use only)
45
What happens if a thrust reverser inadvertently deploys?
FADEC limits respective engine thrust to IDLE
46
What engine thrust ratings are limited to 10minutes? 5min?
10min 1 engine 5min for both
47
What is FLEX?
Reduced takeoff thrust based on assumed temperature (telling the FADEC that it is warmer than it actually is so it will reduce the thrust)
48
Can the FLEX thrust be reduced lower than CLB thrust?
No
49
What is dry motoring? When must dry motoring not be considered?
TBD. Dry motoring cannot be used for a low oil pressure condition
50
If starting engine via air start cart, which engine is the preferred one to start?
Engine 2 is preferred because of the pneumatic system ducts geometry the pneumatic cart may provide less pneumatic pressure when used to start engine 1
51
What is the purpose of the engine battery start checklist?
This procedure allows engine starts with batteries as the only electrical power and a pneumatic source (i.e., HPU or APU bleed air).
52
What powers the FADEC?
The PMA above 50%N2, the electrical system below 50%N2
53
What controls the Fuel Metering Unit?
The FADEC
54
Each thrust reverser HALF has how many hydraulic actuators
2
55
What type of engine is the GE CF34-8E5?
High-bypass 2 spool turbofan
56
During normal engine start, how is the starter control valve operated?
The FADEC opens and closes the starter control valve SCV automatically.
57
How many igniters are energized for each engine start?
1 on the ground, 2 in-flight
58
In what situations is continuous ignition required?
Flight in areas of moderate or heavier turbulence, icing and rain require use of continuous ignition until clear of such areas.
59
Firewall Thrust
Thrust Levers advanced to forward stop.
60
Max Thrust
Thrust Levers forward until just below any EICAS redline parameter (N1, N2, ITT) per CFM limitations.
61
Takeoff Thrust
The minimum N1% required by the airport analysis to meet all performance criteria for a normal Takeoff.
62
TOGA Thrust
N1 set for Takeoff/Go-Around per performance charts.
63
MCT Max Continuous Thrust
Thrust set to, but not to exceed, “max continuous” parameters on EICAS for N1, N2, or ITT per CFM limitations (i.e., “top of green” on most restrictive parameter).
(Max Continuous Thrust CON is the highest thrust that does not require maintenance to inspect the engine earlier than planned. It is used in emergency situations and is 12,800lbs. The highest possible thrust is TO-1 RSV or GA RSV, RSV meaning that ATTCS is activated. TO-1 RSV and GA RSV produce 14,200lbs of thrust or 13,000lbs SE)
64
Max Cruise Thrust
N1 set for cruise power setting per FMS or performance charts.
65
CI Climb Thrust
Thrust set per Cost Index data to obtain specified cruise Airspeed.
66
Max Climb Thrust
N1 set for climb power setting per FMS or performance charts.
67
ATS
Ait Turbine Starter
68
FADEC
Full Authority Digital Engine Control
69
PMA
Permanent Magnet Alternator
70
SCV
Starter Control Valve
71
TMS
Thrust Management System
72
How much engine power can be produced?
13,800lbs up to 14,200lbs on the reserve mode at ISA
73
What type of engine is the CF34-8E5?
High bypass, two-spool, axial flow, turbofan engine
74
What are the different sections of the engine?
Cold section, AGB, combustion liner and stage 1 nozzle assembly, HPT high pressure turbine, LPT low pressure turbine
75
Describe the N1 spool
A single-stage low pressure fan that is driven by a 4-stage low pressure turbine representing the N1 Speed indication.
76
Describe the N2 spool
A 10-stage axial flow compressor with variable geometry inlet guide vanes and stator stages driven by a two-stage high pressure turbine. Represents the N2 speed indication on the EICAS
77
What is the purpose of the AGB?
Provides mounting pads for the IDG and the hydraulic pump.
78
How is ITT measured?
5 thermocouples mounted in the inlet stream of the low pressure turbine sense the gas temperature and send their signals to the FADEC for ITT readouts, hot start logic, and flameout detection
79
How is engine fuel flow measured?
Engine fuel flow is measured within the Fuel Control Unit that sends a signal to the FADEC and to the EICAS for FFPPH indications.
80
What are the 2 subsystems of the engine fuel system?
The Fuel Contol System and Fuel Distribution System which provide the engine with scheduled fuel for combustion
81
What are the components of the Fuel Control System?
Fuel Control System: FADEC, FMU fuel metering unit, PMA permanent magnet alternator, Engine Sensors, Variable Geometry Actuators, and OBV operability bleed valve
82
What are the componets of the Fuel Distribution System?
Fuel Pump, Fuel Filter, Fuel Manifold, 18 Fuel Injectors
83
Where does fuel enter the engine?
The Engine Fuel Pump inlet
84
Where does engine fuel go after leaving the engine fuel pump?
Engine fuel moves to the fuel boost pump and from there is split into 2 paths.
Either fuel is directed to the heat exchanger to the fuel filter back to the boost pump (high pressure side) to be pressurized, to the (FADEC controlled) FMU fuel metering unit to the fuel manifold, to the 18 fuel injectors mounted on the combustor frame.
Or fuel is immediately directed back from the boost pump to the fuel pump for motive flow for the tank ejectors.
85
What is the purpose of the engine heat exchanger?
To cool engine oil and transfer heat fuel, providing icing protection
86
How is fuel generally controlled/metered to the engine?
The Thrust Lever inputs (and other data like pressure alt from the ASCB, T2…) send an electronic signal to the FADEC which controls the FMU fuel metering unit. These inputs allow the FADEC to calculate N1 (low pressure spool) output for any thrust lever position
87
What protections does FADEC provide?
Fuel scheduling is limited to protect engine speeds, temperature ITT, and compressor discharge pressure limits
88
What is the engine fuel EICAS indication system composed of?
Fuel Filter by-pass switch (ENG 1 FUEL IMP BYPASS)
Fuel low pressure switch (ENG 1 FUEL LO PRESS)
Fuel flow measuring device (FFPPH)
89
How are the 2 engine FADEC channels divided?
One channel is in-control and the other is in standby (still processes inputs but all outputs are disabled). Channels A and B. Channels are aternated on each engine start.
90
What provides power to the FADEC?
The 28VDC PMA Permanent Magnet Alternator (28VDC for starting and as a backup)
91
What is the purpose of the engine oil system?
To provide lubrication and cooling to the turbine engine main shaft bearings and the AGB bearings.
92
What is the engine oil/lubrication system composed of?
ABG oil reservoir, lube and scavenge pump (oil pump), oil filtration module (oil filter and filtert bypass valve), and the fuel-oil heat exchanger which cools the oil and heats the fuel - which is then directed to the engine bearings
93
What is the purpose of the ignition system?
Provides an electrical spark for fuel combustion for engine starts and in-flight auto-relights.
94
When starting the engine on the ground, how many igniters are used? How many in flight?
1 on the ground, 2 (both) igniters in-flight
95
What happens when both ignition switches are put in the OVRD position?
Both igniters on each engine are energized (1A, 1B, 2A, 2B) continuously
96
What are igniters 1B and 2B connected to?
SPDA 2
97
Why is only 1 igniter used for ground starts?
So that latent faults can be detected
98
In what situations are both igniters engergized?
Air starts, flameouts, loss of ARINC busses, a missed light-off, or if continuous ignition is requested by the pilot
99
What happens if you turn the ignition OFF in flight?
Nothing. The FADEC disregards the OFF position
100
What does the WML indication mean next the the IGN A B with a FAIL indication in the N1 indicator?
An auto-relight is in progress. The igniters will remain on for 5 seconds after a flameout is detected. If engine re-light does not occur within 30sec, moving the START/STOP selector to STOP will terminate the auto re-light
101
What must the engine starting system design provide during engine start?
Sufficient rotor speed to initiate combustion light-off
and
to obtain self-sustaining engine propulsion
102
What does the engine starting system include?
ATS Air Turbine Starter, SCV Starter Control Valve
103
How does the ATS Air Turbine Starter work?
Beed air is provided to the ATS to rotate the engine rotor and start the engine
104
What does FADEC control for engine start? What doesn’t FADEC control, but the aircraft controls?
FADEC: Fuel Flow, Starter Command, Ignition Command
Aircraft Controls: SCV Starter Control Valve, Hydraulic EDP, switches power to ignition exciters as commanded by the FADEC, manages bleed system interface
105
Describe the engine start beginning with turning the START/STOP selector to START.
START
Pressurized Air is directed to the ATS
ATS rotates the engine rotor via the AGB
FADEC commands ignition and fuel flow on
FADEC schedules fuel flow to idle thrust
FADEC de-energizes the SCV at 50% N2 and turns ignition off
106
How is a windmilling start accomplished?
Engine rotors are turned by airflow
START
FADEC commands ignition and fuel
107
When does the FADEC command ignition on?
7% N2
108
When does the FADEC command fuel flow/the fuel metering valve to open?
20% N2
109
When is the SCV starter control valve de-energized by the FADEC (bleed air removed)?
50% N2
110
What is the difference in start sequence in-flight than on the ground?
In inflight assised start is identical to an on ground start, but the FADEC will open the metering valve if N2 has not reached 20% after 15 seconds
111
Does the SCV open for a windmilling start?
No, because bleed pressure is not available or necessary to turn the rotor
112
What protections does FADEC provide for in-flight starts?
None. The FADEC has no protection for hot starts, hung starts, or failure to light-off for in-flight engine starts. If no light off is detected within 30 seconds after fuel flow is started, the start should be manually aborted.
113
What protections for start does FADEC provide on the ground (WOW)?
Hot start, hung start and no light-off protection
114
Why is the FADEC prevented from protecting against a hot and hung start in flight?
So the FADEC cannot prevent an in-flight engine start
115
What happens when the FADEC prevents a hot start? Will the starter be de-energized?
The hot start protection will terminate the start when ITT rises above 815deg during a ground start by closing the FMV fuel metering valve and by cutting off ignition.
The FADEC will not de-energize the starter driver in this case to allow immediate engine cooling by motoring. Select STOP to de-energize the starter driver and stop dry motoring.
116
When should the in-flight auto relight be considered unsuccessful?
If the engine relight does not occur within 30sec or N2 falls below 7.2%, the auto relight can be considered unsuccessful and should be manually terminated by turning START/STOP to STOP.
117
What are the components of the engine exhaust system?
Bypass air, primary core air, nozzle, thrust reverser system
118
What are the engine stages?
Fan blade platform, high presser compressor, combustor, high and low pressure turbines, primary nozzle
119
What is the thrust reverser connected to?
The aft fan case (cowling)
120
Do thrust reversers allow air to flow when stowed?
Yes. Bypass air exits the engine through the gap between the thrust reverser and core section
121
What does each thrust reverser half consist of?
A fixed structure that supports the transcowl, houses the cascades, and contains the thrust reverser actuation system
122
What mechanically happens when the thrust reverser is deployed?
The translating cowl that was blocking access to the cascades, moves into the bypass air gap on tracks, allowing air to flow through the cascades now, changing the airflow out of the engine
123
How are the thrust reversers powered?
Hydraulically actuated, actuators extend when reverse thrust is selected. Locks and position sensors indicate the REV position indication on the EICAS
124
What prevents the thrust reverser from deploying in-flight?
The FADEC uses WOW and other inputs to prevent thrust reverser actuation in flight.
AND electrical solenoids in the throttle quadrant limit throttle movement below IDLE while WOW is not true
125
What must be true for the thrust reversers to deploy?
WOW with engine running
TLA idle (allows lifting into REV position)
126
Is it possible to use REV thrust on SE?
Yes. Though be prepared for asymetric thrust. May not be allowed per Mesa.
127
If the thrust reverser is deployed in-flight, what is thrust limited to?
Flight Idle
128
What controlls the FADEC when the engines are not running?
28VDC from the essential bus
129
What provides anti-ice to the T2 sensor?
28VDC power
130
What powers the engine ignition system?
AC power
131
When starting an engine, when does power for the starter switch from 28VDC from the ESS BUS to the PMA?
When engine speed is greater than 50% N2.
132
How many positions are there on the throttle quadrant?
5
MAX
TOGA
IDLE
MIN REV
MAX REV
133
What message will appear on the EICAS when the solenoid that prevents thrust reverser movement is unlocked in-flight or locked on the ground?
ENG 1 (2) REV TLA FAIL
134
What is the purpose of the TO/GA switches?
They enable the pilot to manually generate a Takeoff/Go-Around signal
135
What is the purpose of the ATTCS Automatic Takeofff Thrust Control System?
ATTCS provides engine thrust reserve RSV in the event of an engine failure during takeoff, go-around phase or windshear warning detection
136
When is ATTCS armed?
Armed when either thrust lever is at TOGA position during takeoff
or during a go-around
137
How can ATTCS be armed manually?
Whenever the system is armed and either TLA is advanced above TOGA position
138
What will the EICAS show when ATTCS is activated?
The green ATTCS (armed) will change to RSV
139
What is the difference between FLEX TO-1 and FLEX TO-2?
FLEX TO-1 has a maximum flex reduction of CLB-1 while FLEX TO-2 has a maximum flex reduction of CLB-2
140
Where can the TMS thrust management system, AT automatic throttle, TRS thrust rating selection, and ETTS electronic thrust trim system channels be toggled?
MCDU
141
What is the purpose of TRS Thrust Rating Selection menu of the MCDU?
The TRS determines the appropriate thrust rating upper limit based on the phase of flight when in auto mode or based on pilot selection when in manual mode.
142
What is TDS on the MCDU?
TDS is Takeoff Data Set screen is within the TRS Thrust Rating Selection on the MCDU. TDS allows the pilot to change the default takeoff thrust rating.
143
How can the engine be stopped immediately?
By pulling the fire handle
144
What does pulling the fire handle do?
Stops the fuel flow via the Fuel SOV, hydraulic flow via the Hydraulic SOV (isolating the engine side of the hydraulic system from the airframe side), and pneumatic flow via the High Stage Bleed Valve HSBV and Engine Bleed Valve EBV
145
What is the N1 readout indicating?
N1 is a numerical display of the fan rotor speed, displayed as a percentage of total rpm for each engine
146
What is the cyan N1 arc?
The difference between the actual N1 value indicated by the green pointer and the requesested N1 value.
147
What is the cyan tick (not the carrot) on the outside of the N1 dial?
N1 Wing Anti Ice Bug indicates the minimum N1 value when the wing anti ice is on and the aircraft is on the final approach phase
148
What is the max thrust indication on the N1 dial?
The green tickmark
149
What is the ITT indication on the EICAS indicating?
A numerical display of the ITT Inter Turbine Temperature for each engine.
150
What does the ITT redline represent?
The maximum ITT for the certified thrust rating modes
151
What is the ITT amber line and when does it appear in the ITT dial?
The ITT Amberline is only in-flight after hte end of the takeofff phase and represents maximum continous ITT limit
152
What does the engine vibration system consist of?
1 indicator for each engine, where the LP number indicates the N1 rotor and the HP number indicates the N2 rotor
153
When is the engine vibration in the green, amber or red?
Green is 0-3.9
Amber is 4-5
Red is over 5
The CMC and FDR will be able to continue recording vibration levels up to 10 units
154
What is the difference between climb 1 and climb 2?
The CLB-1 mode provides higher rates of climb, so the airplane spends less time to reach a desired altitude when compared with CLB-2 thrust. As a result, considering fuel conservation aspects, the CLB-1 mode would produce the lowest trip fuel burn. The main benefit in using reduced climb is related to maintenance costs. Using reduced climb, the engine works at cooler temperatures, thus minimizing deterioration of engine components.
The preferred climb mode is CLB-2. However, the PIC should not hesitate to select CLB-1 when the situation requires it.
155
What is climb 1?
Maximum Available Climb Thrust
156
What is climb 2? How is it different than climb 1?
Reduced Climb Thrust at sea level, corresponding to approximately 90% of Maximum Climb Thrust at sea level.
The difference between CLB-1 and CLB-2 decreases with altitude.
157
In the event of an engine flameout, what will the FADEC do?
In the event of engine flameout, the FADEC automatically turns on both igniters and schedules fuel flow to initiate the relight process. A WML icon is displayed next to the affected engine N2 and represents that an auto relight is being attempted.
Engine may accelerate to idle slowly during the start, especially at high altitudes. The auto relight is successful if positive steady N2 acceleration is obtained without ITT overtemperature nor any other engine parameter fluctuation. If those conditions are satisfied, the start is progressing normally.
If ITT overtemperature happens, or engine parameters fluctuate the auto relight should be considered unsuccessful and aborted. Crew manually aborts auto relight by moving the START/STOP Selector to the STOP.
If engine restart is considered, follow the ENGINE AIRSTART procedure.
During in-flight engine starts, using auto relight or manual starts, the FADEC has no protection for Hot starts, Hung starts or failure to light off. Crew must take appropriate action in case of an abnormal start.
158
How many actuators do the thrust levers have, and are they electric or hydraulic actuators?
2 Hydraulic Actuators
159
T2 sensor purpose
senses air temperature for fuel scheduling
