Powerplant (Non Oral Exam Guide) Flashcards
What type of engine do we have
CFM-56: high-bypass ratio, twin spool, axial flow turbofan
How many igniters
A and B
What components are part of the engine gear box?
- lubrication unit, including the engine oil pumps
- engine fuel pumps and FCU
- FADEC
- IDG
- engine starter
- engine hydraulic pump
What is FADEC?
Full Authority Digital Engine Control: computer that interfaces with numerous aircraft systems to control engine operation and performance
What types of functions does the FADEC perform?
- control of gas generation
- protection against engine exceeding limitations
- power management
- automatic and manual engine starting sequencing
- thrust reverser control
- fuel recirculation control
- detection, isolation, and recording of failures
How is the FADEC powered?
An internal magnetic alternator
In the event the FADEC’s alternator fails, what happens?
The FADEC will revert to aircraft electrical power
When is FADEC self-powered?
When N2 is above 12%
How can we tell if the FADEC is not powered?
Engine indications are replaced with amber X’s
*also appear 5 mins after engine shutdown
What redundancy does the FADEC have?
- Dual channel redundancy- one channel is active while the other is standby
- If one channel fails, the other automatically takes control
Regarding fuel, what does moving the ENG MASTER switch to off do?
- Commands the closing of the LP and HP fuel shut off valves for that engine’s fuel system
- closes the fuel return valve and opens the bypass valve
During an automatic engine start, what controls the HP Fuel Shutoff Valve?
FADEC
What igniter must be operational for all flights? Why?
Igniter A- only igniter powered when in the Emergency Electrical Configuration mode
When will FADEC activate and terminate ignition?
Activate when N2 reaches 16% and terminates when N2 reaches 50%
What conditions will FADEC automatically activate continuous ignition?
- when a delayed engine start is sensed
- when the Engine Interface Unit (EIU) fails
- when an engine flameout is detected
What is different for the igniters during a manual engine start?
FADEC activates both igniters when the Engine Master switch is placed ON. Ignition stopped when N2 reaches 50%
What is the Thrust Lever Angle (TLA)?
Thrust rating limit and N1 for given position of thrust levers
What are the 3 different idle modes?
- Modulated Idle
- Approach Idle
- Reverse Idle
What is Modulated Idle?
Regulates thrust according to bleed system demands and ambient temps
- In flight: when the flaps are retracted
- On the ground: when reverse is not selected
What is Approach Idle?
Engages in flight when flaps are extended. Idle is regulated according to altitude and is not dependent on bleed system demand
What is Reverse Idle?
Engages on the ground and the thrust lever is in the Reverse Idle position. Reverse Idle is slightly higher than forward idle thrust
When does FADEC command a higher engine idle speed?
- bleed demands
- high engine or IDG temps
- Approach configuration
During start, FADEC controls monitoring and sequencing of:
- start valve opening and closing
- ignition activation and termination
- fuel valve opening
- N1, N2, and EGT exceedance protection
What is the manual start sequence?
- ENG MODE selector: Ignition/Start
- Engine Manual Start pushbutton: ON (engages starter and windmills engine)
- When max motoring speed reached: ENG Master switch: ON (activates ignition for both igniters and opens LP and HP fuel valves)
Does FADEC have abort authority during a manual start?
No, only passively monitors the start and displays sensed abnormalities on the E/WD
Compared to an automatic start, what protections are not provided with a manual start?
- will not provide EGT exceedance protection (unless EGT limit is exceeded prior to 50% N2, then FADEC aborts the start)
- still provides N1 and N2 exceedance protection
Does FADEC have abort authority during an inflight relight?
No
When does the automatic relight logic activate?
When FADEC senses that engine’s N2 RPM has decreased below a pre-set limit
What does a fault light on the ENG panel indicate?
- auto start abort
- position of FUEL HP shutoff valve abnormal
- malfunction of the thrust control
What determines the max thrust the A/THR system will be able to command?
The position detent of the thrust lever
During a normal automatic start sequence; what does moving the ENG Master switch to ON do?
- LP fuel valve opens
- start valve opens
- APU speed increases
- ignition starts: when N2>16%
- N2>50%: start valve closes, igniter off (if on ground), APU speed returns to norm, pack valve reopens after 30 secs
What does pushing the ENG FIRE pushbutton do?
- silences aural fire warning
- arms fire extinguisher squibs
- closes the low-pressure fuel valve
- closes the hydraulic fire shut off valve
- closes the engine bleed valve
- closes the pack flow control valve
- cuts off FADEC supply power
- deactivates the IDG
What occurs when the engine fire TEST button is pressed?
- continuous repetitive chime sounds (CRC)
- MASTER WARN lights flash
- ENG FIRE on the ECAM
- ENG FIRE pushbutton illuminates in red
- SQUIB and DISC light illuminate
- FIRE lights on ENG panel on pedestal
When will FADEC abort a start?
- stalled start
- no light up
- hot start, hung start
