Systems - Powerplant

Question 1

What is the maximum normal takeoff thrust setting for the 700 and 900?

Answer 1

700 = 12,670lbs

900 = 13,600lbs

Question 2

Describe the compressor and turbine section for N1

Answer 2

1 fan,

4 stage low pressure turbine

Question 3

Describe the compressor and turbine section for N2

Answer 3

10 stage axial flow compressor, 2 stage to high pressure turbine

Question 4

What percentage of engine air is bypass?

Answer 4

85% bypass, 15% core air

Question 5

What is different about the first 4 stages of the N2 compressor section?

Answer 5

The first 4 stages have variable stater veins, or variable geometry system (VGVs)

Question 6

Describe the function and actuation of the VGV’s

Answer 6

Actuated with high pressure fuel from FADEC, moves by mechanical by linkage to prevent stalls and surges

Question 7

How is the position, of the variable geometry system, controlled?

Answer 7

FADEC changes the position of the VGV via high-pressure fuel and mechanical linkage

Question 8

Describe the function of the operability valve

Answer 8

Provides additional compressor air flow control - extracts bleed air to offload the compressor during engine starts and high aerodynamic loading.

Programmed by FADEC and hydraulically activated by high-pressure fuel.

Question 9

Which components are located on the accessory gearbox? (AGB)

Answer 9

3-2-1

3 pumps: hydraulic, oil, fuel.
2 sparks: IDGs & FADEC
1 ATS (Air turbine starter)

Question 10

From which compressor stages do we receive bleed air and for what purpose?

Answer 10

6th and 10th. Used for AC, engine start, wing/cowl anti-ice and pressurization.

Question 11

How many igniters exist in the combustion section, and what are their power sources?

Answer 11

2 AC igniter’s.

AC - A is powered by AC ESS BUS

AC - B is powered by DC BATT BUS with a static INVERTER (turning it into AC)

Question 12

If during a battery start, ignition A is active, how will you be able to start the engine?

Answer 12

Wait 15 seconds for the “alternate” start. FADEC will control this.

Switching to ignition B stems from BATT BUS.

Question 13

What happens when continuous ignition is selected?

Answer 13

Both ignition A and B are energized

Question 14

When is continuous ignition required?

Answer 14

Contaminated runway, moderate or greater turbulence or rain, thunderstorms in the vicinity

Question 15

When would FADEC automatically engage continuous ignition?

Answer 15

Close to the critical AOA, detects a disruption in airflow, or auto-relight

Question 16

Where is the probe located that gives us inter turbine temperature information?

Answer 16

Between the high and low pressure turbines (2nd & 4th)

Question 17

When will FADEC be powered by its own alternator? When will it rely on the aircraft electrical power?

Answer 17

Below 50% N2 or failure of FADEC - it will operate off of the aircraft power.

Above 50% N2 the AGB-Mounted FADEC alternator will operate on its own.

Question 18

How many channels are on the FADEC and what if the active channel fails?

Answer 18

Two channels, one always active and one on standby to take over

Question 19

When will the active FADEC channel switch during normal ops?

Answer 19

After every start at 7% N2

Question 20

When will FADEC command a shut down of the engines?

Answer 20

Overspeed (x3) & ITT over temp on start

Question 21

True or false: the thrust levers are mechanically connected to the fuel metering unit.

Answer 21

False, they are connected by wire

Question 22

What happens if left or right FADEC fails completely?

Answer 22

The engine was shut down, flame out

Question 23

What is APR? When would FADEC command it?

Answer 23

Automatic performance reserve.

ENGINE FAILURE OR if thrust levers are in the TOGA detent.

Question 24

When will APR arm during takeoff?

Answer 24

When the N1 RPM of both engines are within 8% of schedule takeoff thrust. 

Question 25

On approach, when is APR armed for go around?

Answer 25

When the approach bit is set (either engine is available, flaps greater than 20 OR the landing gear is down)

Question 26

What would you do if the starter did not cut out automatically at 50% N2?

Answer 26

Press stop switch light, run the QRH

Question 27

When will APR be activated/deactivated by FADEC?

Answer 27

A difference of 15% N1 - cleared when fan speed mismatch becomes less than 13%

Question 28

If you receive a HOT indication/HOT-START, how would FADEC respond?

Answer 28

Abort the start and command a shut down

Question 29

Describe the normal start sequence/indications:

Answer 29

• START illuminates with START status message
• FADEC Applies power and ATS valve opens
• 20% N2 and ITT less than 120
•  thrust to idle
• 50% N2, FADEC removes power from the starter
• Status message removed

Question 30

During an auto-relight, what is FADEC commanding? When would FADEC discontinue an auto relight?

Answer 30

Energizes BOTH igniters.

Would discontinue below 40% N2.

Question 31

What 4 things will happen after pressing TOGA

Answer 31

TO/TO mode on ground, GA/GA select, disconnect auto pilot, update runway possession

Question 32

List the thrust of lever positions/settings logic

Answer 32

TOGA - APR
Climb – MCT
Cruise - proportional increase

Question 33

FADEC continues to calculate to N1 until it’s locked at ____ knots

Answer 33

65 knots

Question 34

True or false: FADEC is in charge of all engine operations

Answer 34

True