Powerplant Flashcards
What drives the accessory gear box?
The N2 compressor, which is driven bu the high pressure turbine.
What items are on the accessory gear box?
- Hydraulic pump
- Fuel pump (3 interconnected on common shaft)
- Oil pump (integral pump & reservoir)
- FADEC alternator
- Integrated drive generator
- Air turbine starter
There are three interconnected fuel pumps within the accessory gear box. What are they?
- Low pressure pump
- High pressure pump
- Motive flow pump
What are the rated thrust outputs of the engines?
Normal is 12,670 and APR is 13,790
What drives the N1 fan?
The low pressure turbine.
How many stages is the low pressure turbine?
Four
What comprises an engine stage?
A stage includes a set of stators and rotors.
How much of the egine’s overall thrust is provided by the N1 fan?
80%
What powers the Variable Geometry (VG) vanes?
Fuel pressure directed by the FADEC.
What is the operability valve?
The operability valve works in conjunction with the VG vanes to remove internal air pressure from the compressor section of the engine reducing compressor stall/
What powers the operability valve?
Fuel pressure directed by the FADEC.
How is fuel heated prior to combustion?
Through the use of a fuel/oil heat exchanger.
How many channels does the FADEC have, and when do the channels change?
Two. The channels change with the N2 RPM falls below 7% on every other engine shutdown.
How many FADEC channels are in use at once?
One channel commands the engine while the other channel monitors the controlling channel and is in standby in case the commanding channel fails.
Is there ever a time when both FADEC channels will command the engine simultaneously?
In an engine overspeed situation both FADEC channels will command the fuel valves to close to bring the speed into the normal range.
What happens if both FADEC channels fail or the FADEC loses power?
The engine will fail.
Can the left engine’s FADEC control the right engine?
No.
Do the left and right engine’s FADECs cross talk with one another?
Yes. They compare engine speed and thrust reverser information.
While cross talking, when will one engine’s FADEC assume the other engine has failed?
When there is a difference of at least 15% N1.
When an engine fails, what will the oeprative engine’s FADEC automatically command?
APR in the TOGA detent, MCT in the climb detent, and a proportionate increase throughout the cruise range.
What will the FADEC command is a thrust reverser deploys in flight?
It will reduce that engine’s thrust to idle.
At what speed does the FADEC lock in the final N1 computation during takeoff?
65 KIAS.
What powers the FADEC?
Aircraft electrical power with an N2 of less than 50%, and the FADEC alternator with an N2 of greater than 50%.
If we wait for the FADEC to shut the engine down during a hot start are we gayranteed that the ITT limit will not be exceeded?
No.
Will the engine automatically shutdown for a hot start on the ground?
Yes.
Is there ITT protection and subsequent auto shutdown in flight?
No.
What is the time limit for single engine APR thrust?
10 minutes.
What is the time limit for normal or FLEX thrust?
5 minutes.
When will the L or R OIL LEVEL Lo status message appear?
Below 57% with the engine running and below 80% with the engine stopped.
What is FLEX thrust?
It is a reduced power setting for takeoff calculated using an assumed temperature.
When using FLEX for takeoff, what must the pilot in command verify prior to takeoff?
The PIC must verify that the computed thrust displayed on the primary display is equal to or greater than that required in QRH v.1.
What color will the FLEX thrust rating be displayed in on the primary display?
Magenta.
When is FLEX thrust not permitted?
- Wing and/or cowl anti-ice bleeds are in use.
- Runway is contaminated with standing water, slush, snow, or ice.
- Warnings or forecasts of windshear or downdrafts exist.
- Antiskid system is inoperative.
What stages of the engine is bleed air extracted from?
6th and 10th stage.
Can both stages be used at once?
No.
What powers the igniters?
Igniter A is powered by the AC essential bus, and igniter B is powered by the aircraft battery and an inverter.
When is the use of continuous ignition required?
- Flight in the vicinity of thunderstorms.
- Flight through moderate or severe turbulence.
- Flight through moderate or severe rain.
- Operations on a contaminated runway.
When will the continous ignition fire automatically?
- When the FADEC senses a flameout.
- When approaching a stickshaker during a stall.
- When a disruption of airflow is detected through the engine.
How are the thrust reversers actuated?
Hydraulically.
How are the thrust reversers locked?
Hydraulically, and mechanically.
What is the maximum ITT for engine start on the ground and in flight?
120 on the ground, 90 in flight.
What is the maximum altitude for engine re-light?
FL210
What are the five different engine idles?
- Flight idle
- Approach idle
- Landing idle
- Reverse idle
- Ground idle
When is APR armed on takeoff?
When within 8% of target thrust.
When is the go-around mode armed on approach?
With the gear extended or the flaps greater than 20.
What does the blue circle indicate on the N1 guage during cruise (CRZ) flight?
The maximum thrust setting for cruise (less than MCT).
What are the engine warm up limitations?
The engines must remain at idle until the oil pressure is in the normal range. Do not exceed 75% N1 until all indications are in the green or two minutes has passed, which ever is greater.
What is the engine cool down limitation?
After landing the engine must be at or near idle thrust for two minutes prior to shutdown.
