FADEC

Question 1

How many light are associated with FADEC failure?

Answer 1

3 light conditions

1. GOV Red - Major failure (stepper motor frozen
2. GOV Amber - Minor failure (response time may be affected but the essential control functions are ensured
3. GOV Flashing Amber - when twist grip leaves the “Flight” position. Minor fault (redundancy failure) no effect on engine performance

Question 2

Where is the ECU located?

Answer 2

Mounted in the cargo compartment

Question 3

How is fuel flow governed?

Answer 3

2 fuel metering valves/units in the HMU

Main Fuel Metering Unit
Back-up Fuel Metering Valve (EBCAU)

Question 4

Describe the Main Fuel Metering Unit

Answer 4

• Needle assembly which regulates fuel flow
• Dual actuators (2 step motors - Channel A and B) drive the needle assembly based on ECU signals
• Position transmitter send needle info to ECU

Question 5

Describe the Back-up Fuel Metering Unit

Answer 5

EBCAU. Purpose: back-up governing and fuel metering valve
- composed of a back-up electrical actuator
- actuator controls a valve
- valve allows flow of additional fuel

Question 6

What happens when a Major FADEC failure occurs

Answer 6

1. FADEC freezes position of Main Fuel Metering Valve
2. FADEC sends “major failure” signal to EBCAU
3. EBCAU activated - red + amber GOV lights ON
4. EBCAU maintains constant N2/Nr