A320 Lounge Powerplant Flashcards
(72 cards)
1
Q
Where in the engine does bleed air come from?
A
High pressure compressor
2
Q
How many stages in the high pressure compressor?
A
CFM56 - 9 stages
LEAP1A - 10 stages
3
Q
How many stages in the low pressure compressor?
A
CFM56 - 4 stages
LEAP1A - 3 stages
4
Q
What type of engine is a CEO?
A
CFM56
5
Q
Are left and right engines identical?
A
Yes
6
Q
What is the journey of air through the engine?
A
Fan
Low pressure compressor
High pressure compressor
Combuster
High pressure turbine
Low pressure turbine
7
Q
How many stages in the high pressure turbine?
A
CFM56 - 1
LEAP1A - 2
8
Q
How many stages in the low pressure turbine?
A
CFM56 - 4 stages
LEAP1A - 7 stages
9
Q
How many stages in each part of the CFM56?
A
Low pressure compressor - 4
High pressure compressor - 9
High pressure turbine - 1
Low pressure turbine - 4
10
Q
How many stages in each part of the LEAP1A?
A
Low pressure compressor - 3
High pressure compressor - 10
High pressure turbine - 2
Low pressure turbine - 7
11
Q
What part of the engine is the accessory gearbox driven by?
A
HP (N2) shaft
12
Q
What does the accessory gearbox power?
A
Engine oil pump
Engine fuel pump
Engine driven hydraulic pump (G,Y)
Engine driven GEN (GEN 1 and GEN 2 via IDG)
Pneumatic starter for engine start
FADEC alternator
13
Q
How are the FADECs powered?
A
Powered by electrical system, but when engine is getting up to speed, then self-powered, because alternator connected to accessory gearbox
14
Q
What is the N1?
A
Fan
Low pressure compressor
Low pressure turbine
15
Q
What is the N2?
A
High pressure compressor
High pressure turbine
16
Q
How many FADECs per engine?
A
1
17
Q
How many channels per FADEC?
A
2
18
Q
When do FADECs become self-powered?
A
CEO - N2 above 12%
NEO - N2 above 8%
19
Q
What does EIU stand for?
A
Engine interface unit
20
Q
What does the EIU do?
A
Interface computer between our controls and the engine
21
Q
What are the EIU inputs?
A
Engine start buttons and switches
ACSC
LGCIU
Anti-ice
FMGS (A/THR)
22
Q
What does ACSC stand for?
A
Air conditioning system controller
23
Q
What is the ECU?
A
Engine Control Unit
On NEO aircraft, this was the original name for the FADEC, but is now referred to as FADEC
24
Q
What are the inputs to the FADEC?
A
ADIRS
Thrust lever angle
Engine sensors
EIU
25
What are the outputs of the FADEC?
Engine cooling and stability control
Ignition system
Fuel return valve
Start valve
Thrust reverser system
E/WD, SD
26
What are the FADEC channels powered by?
Channel A - DC ESS BUS
Channel B ENG 1 - DC BATT BUS
Channel B ENG 2 - DC BUS 2
27
Can you start an engine if the EIU is not working?
No - the engine start signal runs through the EIU to get to the FADEC. If the EIU is failed, the signal has nowhere to go.
If the engine is already running and there is an EIU fault, it will continue running, but once off, cant be restarted
28
What information will be sent to the E/WD and SD with a FADEC failure?
They wouldn't send information, and hence there would be amber Xs
29
What happens if an engine is started and the thrust lever isn't at idle?
The engine will start regardless of the TL position and thrust will increase to match the TLA. An ECAM caution will warn the flight crew
30
How many idle thrust settings are there?
3
31
What are the three thrust idle settings called?
Modulated idle
Approach idle
Reverse idle
32
What is modulated idle?
When is it active on a CEO?
Idle thrust is regulated according to bleed system demand
Selected in flight when flap lever position is zero
Selected on the ground provided reverse is not selected
33
What is approach idle?
When is it active on a CEO?
Idle thrust is regulated according to aircraft altitude, regardless of bleed system demand
Selected in flight when flaps lever is not at zero
Allows the engine to accelerate rapidly from idle to go around thrust
34
How long does thrust take to get from idle to TOGA in a go around?
8 seconds
35
What is reverse idle?
When is it active?
Selected on the ground when the thrust lever is in the REV IDLE position
Is slightly higher than forward idle thrust
36
What is the change for modulated idle in a NEO?
It is called minimum idle
It is selected in flight when the gear is retracted and the flaps not in CONF 3 or CONF FULL
37
What is the change for approach idle in a NEO?
Activated in flight when the gear is down and flap lever in CONF 3 or CONF FULL
The theory is that approach idle isn't necessary from a long way out on the approach, allowing the aircraft to use a lower idle for initial stage of the approach and save fuel, as the agility of the engine isn't as important higher up
38
What is an engine surge?
As air moves through the engine, it goes from a high pressure to a low pressure. Surge is when the air tries to move backwards in the system, as air naturally wants to go from higher pressure into lower pressure areas
39
Where in the CEO engine is bleed air taken for pneumatics?
High pressure compressor
5th and 9th stages
Intermediate from the 5th stage and high pressure from the 9th stage
40
Is pressure increasing or decreasing through the stages of the high pressure compressor?
Increasing
41
Where is engine anti-ice air taken from on a CEO engine?
From its own engine, at the 5th stage of the high pressure compressor
42
Where is bleed air taken from a CEO for the hydraulic system?
9th stage of the high pressure compressor
43
Where in the NEO engine is bleed air taken for pneumatics?
High pressure compressor
4th and 10th stages
Intermediate from the 4th stage and high pressure from the 10th stage
44
Where is engine anti-ice air taken from on a NEO engine?
From its own engine, at the 7th stage of the high pressure compressor
45
Where is bleed air taken from a NEO for the hydraulic system?
10th stage of the high pressure compressor
46
What is the first valve that fuel reaches in the engine called?
What controls it?
LP fuel shutoff valve
Controlled by the engine master switch, or the engine fire push button
47
What does the fuel go to after the LP fuel shutoff valve after entering the engine?
Low pressure pump - this energises the fuel in the engine system
48
Where does the fuel go after the low pressure pump?
Splits in two.
Some goes to a fuel/oil heat exchanger
This heats up the fuel, and removes heat from the oil. The fluids dont mix.
Some goes to recirculation
49
Where does fuel go after the fuel oil heat exchanger?
Over a filter, then onto HP pump (which is connected to N2)
50
What is the collective name for the LP pump, HP pump and filter?
Fuel pump unit
51
Where does fuel go after the HP pump?
It splits in two
Some goes over another heat exchanger called the servo/fuel heat exchanger (which still just exchanges heat with the engine oil), then into the hydro-mechanical unit
The other fuel goes to the fuel metering valve
52
What is the route the engine oil takes in a CEO?
Hot from the accessory gearbox, it goes over the servo/fuel heat exchanger, then over the fuel/oil heat exchanger, where it is cooled.
The cool oil then reenters the oil tank. From the oil tank, it is pumped back to the accessory gearbox
53
What is the route the engine oil takes in a NEO?
Same as CEO, except the tank and the gearbox are swapped, so the tank contains hot oil, and oil is cooled before entering the accessory gearbox
54
What is the purpose of the hydromechanical unit?
Fuel is essentially used as a hydraulic fluid to control actuators, opening and closing valves in the engine, which enables the FADEC to manage the various bleed valves
55
What is the fuel metering valve?
Valve opens and closes to regulate the amount of fuel that goes into the nozzles
56
Where does fuel go after passing over the fuel metering valve?
Goes over a HP fuel shutoff valve, and then into the engine nozzles for combustion
57
What controls the HP fuel shutoff valve?
The engine master switch
The HP fuel shutoff valve is at the end of the fuel's path through the engine, so shutting this valve switches off the engine pretty quickly
58
If shutting off an engine using the engine fire push button, how long could it take for the engines to switch off? Why?
Could be 2 minutes
Because the engine fire push button only controls the valve at the beginning of the fuel's journey through the engine, so fuel already in the system continues running the engine until this has been used up
59
Where does the IDG cooling fit into the engine fuel system?
Fuel from downstream of the HP pump is taken into a recirculation route, where it is used for IDG cooling, and then mixed with cold fuel to be added back into the fuel tanks
60
What temperature is the fuel at the fuel return valve, as it goes back into the fuel tanks?
100C or less
61
What is the hydromechanical unit called in a NEO?
In the NEO it is split into two systems, the SCU and SVA
Split Control Unit
Servo Valve Assembly
62
What is the heat exchanger difference in the NEO?
Fuel Oil Heat Exchanger and IDG oil cooler have swapped positions
63
What is the difference in pumps on a NEO?
There is now a MFP
Main Fuel Pump
This is a new system which incorporates LP and HP fuel pump together. The HP is still powered via N2 shaft
64
What does turning the engine mode selector to start on CEO do?
Energises FADEC
Closes Pack Flow Control Valve
Don't want air conditioning system using bleed air
It also calls up the ENG SD page
65
What does putting the engine master switch to on on CEO do?
LP fuel shutoff valve opens
Starter valve inline
N2 16% - Ignitor A or B on
N2 22% - HP fuel shutoff valve opens
66
Which ignitor system is used? A or B?
The opposite to the last engine start
67
What happens at N2 50% on CEO?
Start valve closes
Ignitor stops
30 seconds later, pack flow control valve opens
68
What does turning the engine mode selector to start on NEO do?
Energises FADEC
Closes Pack Flow Control Valve
Don't want air conditioning system using bleed air
It also calls up the ENG SD page
69
What does putting the engine master switch to on on NEO do?
LP fuel shutoff valve opens
Starter valve inline
N2 15% - Ignitor A or B on
N2 20% - HP fuel shutoff valve opens
These percentages are 'at or above', and FADEC picks the appropriate time to act
70
Why do LEAP1A engines sometimes dry crank for up to a minute when starting?
When engines are sat on stand, the hot air rises and the top of the spool would be hotter than the bottom, so the top of the engine wanted to expand relative to the bottom.
The early cranking mixes this air and reduces this effect, helping maintenance and durability.
71
What happens on a NEO at the end of the engine start?
N2 55% - Ignitor stops
N2 63% - Start Valve shuts
N2 63% + 60 seconds - Pack flow control valve opens
72
What is the FCTM guidance regarding reverse thrust in the case of inoperative reversers?
If at least one reverser is operative, the general recommendation is to select reversers on both engines during RTO and landing
