FAA Aviation Mechanic Powerplant (AMP)Turbine EnginesEasy
A modern turbofan engine is equipped with a Full Authority Digital Engine Control (FADEC) system. A technician explains this system to a new hire. Which statement best describes FADEC?
- AFADEC is limited to controlling only engine anti-ice and bleed air valves
- BFADEC uses a hydromechanical fuel control as the primary control with electronic trim only as backup
- CFADEC electronically controls all aspects of engine operation, including fuel scheduling, with no hydromechanical backup control required
- DA hydromechanical unit schedules fuel flow while FADEC only displays engine parameters to the flight deck
Show answer & explanationAnswer & explanation
Correct answer: C. FADEC electronically controls all aspects of engine operation, including fuel scheduling, with no hydromechanical backup control required
FADEC (Full Authority Digital Engine Control) is a digital electronic system that has complete authority over engine operating functions such as fuel scheduling, starting, and limit protection, eliminating the need for a separate hydromechanical backup control on most installations.
Why the other options are wrong
- A. FADEC controls far more than just anti-ice and bleed air, including fuel flow, starting, and limit protection.
- B. This reverses the roles; FADEC is primary, not a backup to hydromechanical control.
- D. This describes an older hydromechanical FCU with electronic trim, not FADEC.
FADEC
A digital electronic system with complete authority over turbine engine operation, including fuel scheduling, starting, and limit protection.
- Full Authority = no separate hydromechanical backup needed
- Uses engine sensors and an Electronic Engine Control (EEC) computer
- Automatically protects against exceedances like overspeed and overtemperature
Memory trick: FADEC: Fully Automatic, Digital, Engine Command