BAG 5 PowerPlant

Question 1

At what percentage is N1 self sustaining and the fuel igniters shut off?`

Answer 1

45%

Question 2

What is the RPM output after the reduction gear box?

Answer 2

6,000 RPM output shaft speed

Question 3

The gas generator section consists of?

Answer 3

an axial compressor, centrifugal compressor, a combustion chamber, and a gas generator turbine (N1).

Question 4

Gas generator rpm at 100% N1?

Answer 4

52,000 rpm

Question 5

Free power turbine at 100% (N2)

Answer 5

39,000 rpm

Question 6

What measures the rotational speed?

Answer 6

N1= N1A, N1B, N1C
N2= N2A, N2B, N2C

Question 7

What are the N1 speed pick up sensors?

Answer 7

Electromagnetic sensors mounted on the Full Authority Digital Engine Controller (FADEC) alternator drive shaft.

Question 8

What is N1C?

Answer 8

signal (N1C) is sent to the Emergency Backup Control
Auxiliary Unit (EBCAU) for engine control in the event of a major FADEC failure, and Vehicle and Engine
Multifunction Display (VEMD) for cockpit display.

Question 9

What is N1A and N1B?

Answer 9

The secondary and tertiary N1 signals which are used by the FADEC (N1A and N1B) for engine control, are derived from the dual-channel engine alternators.

Question 10

Which accessories are driven by the gas generator, N1?

Answer 10

The gas generator drives the starter generator, oil pump, fuel pump, and the FADEC alternator.

Question 11

What is N2A?

Answer 11

N2A is transmitted directly to the pilot NR gauge in the cockpit.

Question 12

Where are the free power turbine speed sensor pick ups located?

Answer 12

The rotational speed is measured by three sensors (N2A, N2B, N2C) located on the reduction gearbox casing and power turbine case.

Question 13

What is N2B AND N2C?

Answer 13

N2B and N2C are transmitted to the FADEC

and VEMD for N2 speed control and overspeed protection.

Question 14

Which accessories are driven by the power turbine?

Answer 14

Accessories driven by the power turbine include

the output shaft and the engine compartment cooling fan.

Question 15

Each engine has independent overspeed protection provided by which unit?

Answer 15

Each engine is provided N2 overspeed protection by its respective DECU in conjunction with the Engine
Interface Unit (BIM) located in the baggage compartment.

Question 16

When, why, and how would Engine Interface Unit (BIM) shutdown an engine?

Answer 16

When the N2 reaches a speed of 429 RPM +/−4
RPM, the Digital Engine Control Unit (DECU) will operate the stop electro-valve via the BIM and shut the
engine down

Question 17

If the BIM shuts down an engine, what follows?

Answer 17

Once an engine is shut down by the DECU via the BIM, overspeed protection is automatically inhibited on the second engine. Once an overspeed has occurred, it will remain in overspeed mode until the BIM has been reset.

Question 18

Which systems acts as start-relay between the DECU and engine?

Answer 18

The Engine interface Unit (BIM) acts as a start relay between the DECU and the respective engine.

Question 19

Fuel System Operation

direction of travel

Answer 19

1. Low pressure unit (from the boost pumps)
2. fuel/oil heat exchanger
3. Fuel filter
4. low pressure switch (activates ENG FUEL P on WCA @ less than 8.4PSI)
5. high pressure pump, then into the fuel metering unit (controlled by the FADEC)

Question 20

Fuel Warnings

FUEL FILT 1 or 2

Answer 20

If the pressure difference across the filter increases to approximately 10 psi, the preblockage switch will close and illuminate the FUEL FILT 1 or FUEL FILT 2 caution light on the WCA. Bypass occurs at 17 psi or greater.

Question 21

What happens if the dual stepper valve fails?

Answer 21

a FADEC FAIL caution light will illuminate on the WCA panel. When the FADEC sends a fuel demand to the metering unit, the unit actuates a dual stepper motor that controls the fuel flow and returns a signal to the FADEC. This return signal tells the FADEC that the fuel adjustment was made and whether or not the
stepper motor is working properly.

Question 22

Describe the engine oil transmitter.

Answer 22

Each engine transmitter is connected to the ENG OIL 1
and ENG OIL 2 psi indicators on the VEMD. The indicating scales are graduated from 0 to 140 psi. When
oil pressure drops below the 25 psi minimum, the respective warning light, ENG 1 OIL P or ENG 2 OIL P,
located on the WCA panel, illuminates in addition to the red engine status light located on the overhead
quadrant.