Engines (CFM) Flashcards
During engine start the amber FAULT light on the ENG MASTER panel goes on. This indicates…
A failure in the automatic start sequence.
Can the engines be overboosted in the TOGA position?
No because the ECU provides engine protection limit by monitoring N1 N2 and HMU fuel flow adjustments.
During normal operation at what detent are the thrust levers positioned once the thrust reduction altitude has been reached?
CL.
During the automatic start sequence of ENG 2 you noticed that only igniter B is powered. Is this normal?
Yes igniters are used alternately for engine start.
Continuous ignition is provided automatically when…
Engine flameout is detected and/or the EIU fails.
When does the self powering of the FADEC start?
The FADEC system is self-powered above 58% N2.
What is the main parameter to control the engine thrust?
N1.
Where can you find the thrust reduction altitude and is the number always the same?
TAKE OFF PERF page of the MCDU (it can be modified).
After take off the A/THR will not become active until…
The thrust levers are placed in the CLIMB position.
What is required for the FADEC to compute a reduced thrust setting?
A FLEX temperature must be entered on the TAKE OFF PERF page of the MCDU.
Holding the A/THR instinctive disconnect pushbutton’s for more than fifteen seconds will…
Disengage the A/THR (including Alpha Floor) for the remainder of the flight.
When does the oil pressure indication turn into red?
The oil pressure indication turns red and a warning appears on ECAM when the oil pressure drops below 13psi.
What is the purpose of the Hydromechanical Unit (HMU)?
The HMU controls fuel flow to the engine combustion chamber controls fuel hydraulic signals to actuators and protects against overspeeding.
What is the function of the FADEC during a manual start?
Passive monitoring of the start sequence to close the start valve and cut off the ignition on the ground.
When does oil quantity indication begin to pulse?
Decreasing below 5qts.
A few seconds after selecting reverse the amber REV indication changes to green. What does this mean?
The reversers are now fully deployed.
When does the oil quantity indication pulse?
The indication pulses when oil quantity goes below three quarts (decreasing) or above five quarts increasing.
Which steps of a manual start are being taken care of by the FADEC?
Starter valve closure and ignition cut off.
When does the oil pressure indication pulse?
The indication pulses when oil pressure exceeds 90psi (increasing) or 85psi (decreasing) or oil pressure drops below 16psi (drecreasing) or 20psi (increasing).
You are about to take off. You have not inserted a FLEX temperature. Can you still take off?
Yes but only using the TO/GA detent.
Which idle modes are available?
Modulated idle approach idle and reverse idle.
During an engine start sequence the grey background on N2 disappears at about 57%. What does this indicate?
The start sequence has finished and all engine parameters have stabilized.
What are the main components of the CFM 56-xx engine?
Low-pressure (LP) compressor/turbine high-pressure (HP) compressor/turbine combustion chamber and accessory gearbox.
What controls the engines in all operating regimes?
FADECs (Full Authority Digital Engine Control)
When would you use a manual start?
After aborting a start because of:
- Engine Stall
- Engine EGT overlimit
- Low start air pressure
When expecting a start abort because of:
- Degraded bleed performance due to hot conditions or at high altitude airports
- An engine with a reduced EGT margin in hot conditions or at a high altitude airport
- Marginal performance of the external pneumatic power group
How many igniters fire during a Normal automatic ground start sequence?
- One igniter with the other serving as a backup
- The FADEC automatically alternates the igniters (A and B) at each start
How many igniters fire on a manual or in-flight start?
Both A and B
What control the engine LP fuel valves?
- Engine MASTER switch
- ENGINE FIRE pushbutton
What functions does the FADEC control?
- Fuel metering
- Engine limits based on thrust lever angle
- Start sequencing
- Provides engine indications and thrust limit displays on the E/WD
What redundancy does the FADEC have?
Dual channel redundancy - one channel is active while the other is standby
When will the FADEC abort a start?
- Hot Start
- Stalled Start
- No Ignition
If the FADEC detects a fault during automatic start, is any crew intervention required?
No. The FADEC will discontinue the start, clear the engine, and attempt a restart (if warranted) automatically
When does the FADEC command a higher engine idle speed?
- Bleed Demands
- Approach Configuration
- High engine or IDG temperatures
What are the primary differences between an automatic and manual start?
- Automatic Start: The FADEC provides full monitoring during start and will provide appropriate ECAM cautions and procedures to follow in the even of a start fault.
- Manual Start: Automatic start interruption and auto-crank are not available
What is the rated thrust of each engine?
- A319: 23,500 lbs
- A320: 27,000 lbs
Explain the Normal Start sequence.
- ENG MODE to IGN/START
- ENG MASTER to ON
- Observe Start Valve Open and gray N2 background
- At 16% N2 Ignition (A or B) on
- At 22% N2 HP Fuel
- At 50% N2 starter cutout
- Approximately 58% grey N2 background disappears
- Idle at 60%
Explain the Manual Start sequence.
- ENG MODE to IGN/START
- ENG MAN START pushbutton ON
- At maximum N2 motoring speed (Min 20%), ENG MASTER ON
- Observe AB ignition, fuel flow increase, EGT and N1 increase in 15 seconds
- At 50% observe N1 starter cutout and Ignition off
- ENG MAN START pushbutton OFF
What does a fault light on the ENG panel indicate?
- Auto Start Abort
- Switch disagreement between HP valve and its commanded position
With the ENG MODE selector in the IGN/START what occurs when you press the ENG MAN START pushbutton?
- The start valve opens
- Both pack flow control valves close
What does an amber “FAULT” light in the ENG PUMP pushbutton indicate?
- Pump pressure low
- Overtemp in the reservoir
- Low air pressure in the reservoir
- Low quantity in the reservoir
Will the start valve then automatically close?
Yes, at 50% N2
What causes the amber “FAULT” light on the ENG 1 BLEED and or ENG 2 BLEED pushbutton? (OOLD)
- Overpressure - Downstream of the bleed valve
- Overheat
- Leak - low pressure
- Discontinuity - APU bleed valve open and engine bleed valve not closed or Engine Start with bleed valve not closed
What are the two functions of the engine bleed valves?
- Pressure Regulation
- Shut off Valves
