Power Plant Flashcards
When the Engine is running, what causes the Igniters to operate automatically?
EIU failure, flame-out detected and after the second start attempt failed
What does FADEC do following an Automatic Start Abort?
Hot, Hung, Stall, No Light-off
Runs an abort sequence, if a start aborts on the ground, the FADEC:
Closes the HP valve.
Closes the start valve.
Turns off ignition.
Cranks the engine, after the start abort in order to clear out fuel vapours.
Controls any additional start attempts.
During a Normal (Auto) Start what happens at 16%, 20%, 55% and 63% N2?
@ 16% ignition starts (on ground)
> 20% HP fuel valve opens -> EGT increases -> N1 increases
55% Ignition stops
63% Start valve start closing
- APU speeds returns to normal
- Pack valves reopen if another engine is not started within 60 sec.
Which is the only malfunction, which will cause an auto-abort of an Engine MAN START?
On the ground, if the start EGT limit is exceeded before reaching 50% N2, the FADEC aborts the start, in this case only.
Man Start: When should the MSTR switch be selected ON?
At max N2, at least 20%.
Man Start: What happens when the MASTER switch is selected ON?
Both igniters comes, LP + HP fuel valves open, when N2 > 63% start valve closes and if on the ground, ignition stops. APU speed returns to normal if APU was used.
Man Start: what closes the start valve? And When?
FADEC at approximately 63% N2, on the ground, then cutting off the ignition.
What causes the FAULT light to illuminate on the engine panel?
Amber light comes on, caution appears on ECAM, if there is an automatic start abort, a disagreement between the HP fuel valve position and its commanded position, or a malfunction of the thrust control.
What do MAN START pushbuttons control?
ON: start valve opens if the ENG MODE selections is set to CRANK or IGN/START and N2 < 20%, both packs valves close during the start sequence, start valves closes when N2 > 63%.
What is at one end of the TRANSIENT N1, and what is at the other?
Actual N1 (Green) and N1 command (N1 trend) in green.
On the EGT what does the amber index indicate?
The amber index appears at 750 degrees during engine start, then 1025 degrees (max EGT).
What does REV in amber / green indicate?
Amber: when nay one blocker door is unstowed or unlocked.
Green: when all four doors are fully deployed.
How can you tell that the Start Sequence has finished?
Amber arc increases from 750 degrees to 1025 degrees (max start – max continuous EGT).
Grey background N2 box disappears.
AVAIL indication on N1 indicator (10 sec steady on ground, 1 min pulses in flight)
When does IDLE indication appears (between the N1 gauges)?
When both engines are idle, and in flight. Pulses for 10 sec and then remains steady.
When is FUEL USED set to zero?
The green number is computed by the FADEC, it resets when the engine starts on the ground.
What are the limiting EGT, and operating time, at TOGA power?
1060 degrees: 5 mins (2-engines) or 10 mins (1-engine)
What are the starter limitations?
3 consecutive cycles, 60 sec pause between each cycle
(Maximum 2 min start cycle time for manual start)
No running engagement of the starter when N2 is above 63%
15 min cooling period, following 3 failed cycles
What is the minimum IAS for Full Reverse Thrust?
70kts
Why should Engines be operated at Idle for several minutes before take-off?
> 3 mins to ensure centre tank pump test finished, engine wear, to prevent thermal shock.
When, and for how long, are FADECs powered?
First 5 mins after aircraft is powered, then self-powered above 10% N2 until 5 mins after 2nd engine shutdown.
What is on the N1 shaft?
Fan, LP compressor and LP turbine
What is on the N2 shaft?
HP compressor and HP turbine
What is on the accessory gearbox and what are they powered b
Fuel PumpOil PumpAlternatorPowered by the N2 shaft
What are the functions of the FADECs?
Fuel flow, thrust reverser and ignition controlN1, N2 and EPR limits protectionEGT limits protectionStarter engagement time and speed protectionFuel and Thrust limit computationsComputation of thrust penaltiesAccelleration and deceleration schedulesIdle settingsEngine information to cockpit
What does the FADEC control during ground starts?
Controls start sequenceProvides full protectionsHas start abort authority
What FADEC feature is only available during ground starts?
Start abort authorityEGT protection
What does the FADEC do during manual starts?
Monitors and provides cautions and warnings
What are the 3 idle settings?
Modulated Idle: on ground and in-flight when slats retracted (lowest idle, long spool up times)Approach idle: in-flight when slats are extended (low spool up time for go arounds)Reverse Idle: REV IDLE position (slightly higher than modulated idle)
How is (EPR) Engine Pressure Ratio calculated?
P5 (LP turbine exhaust) vs P2 (engine inlet pressure)
What are the 2 modes of the FADEC for setting thrust?
EPR (Engine Pressure Ratio)N1
When the FADEC regulates thrust in EPR mode, what are the pa
Thrust Lever Angle (TLA)AltitudeMach NumberAmbient TemperatureAir inlet total temperatureAir bleed demands
When EPR mode fails, the FADEC reverts to N1 mode. What impo
No AutothrustNo Alpha Floor
What are the 2 types of N1 mode?
Rated N1 modeUnrated N1 mode
What is the difference between Rated and Unrated N1 modes?
Rated N1 Mode: N1 limits and protections are displayed on E/WD, can be selected manuallyUnrated N1 Mode: Used with EPR and Rated N1 mode failures. N1 limits not displayed and FADEC provides limited overspeed protection. (emergency)
What is the redundancy within the FADEC?
Channels A and B provide backup and redundancy
When does the engine alternator provide power to the FADEC?
N2>10%