Can anyone differentiate FADEC and EEC system in an aircraft Engines?

As I was working related to Engine controlling. I got confused of FADEC and EECs. As per some of the doc. I read like EECs are a part of FADEC.


3 Answers 3


The EEC is the Engine Electronic Controller, the digital processing heart of the Full Authority Digital Electronic Controller. Kind of like the microprocessor in a digital computer. From The Jet Engine by Rolls Royce, 5th edition:

enter image description here

The EEC is dual redundant with all subs-systems such as sensors, cables etc duplicated, so that a single fail leaves the system fully operational. It is housed either in the airframe, or like in civil airliners on the engine, leaving it in need of protection of extreme circumstances:

  • Temperature - ice and tropical heat.
  • Electromagnetic radiation - lightning and airport radar
  • Engine vibration

enter image description here

The FADEC monitors inputs such as:

  • Shaft speeds
  • Engine temperatures
  • Oil pressures
  • Actuator positions
  • Power setting

and then sets fuel flow, variable stator vanes, and air bleed valves.


UTC's product description might help here:

The system consists of an electronic engine control, along with other accessories that work together to optimize fuel management and engine performance during takeoff, flight and landing.

In addition, we provide prognostics and health management electronics that provide more engine diagnostics and prognostics, which can alert the operator to needed maintenance actions before they become an expensive and time-consuming problem. Other technologies include advanced sensing systems

EEC or ECU is the main component of FADEC. It controls the engine actuation system depending upon the situation and the commands received from cockpit. It receives data from all the sensors, commands from cockpit. It processes the data and figures out what control commands need to be given to the actuation system and then execute them. While FADEC is an overarching system which includes EEC and some other components in it, such as sensors, health monitoring system etc. I think, a FADEC typically contains more than one EEC/ECU for redundancy.


EEC is a supervisory system which controls engine parameters and operation to prevent parameter exceedance (temperature, RPM, etc.),and comes into operation at certain engine speeds. It has a backup in case all the channels of EEC are lost.

FADEC is a full authority system, i.e. it controls engine operation and parameters at all speed regimes. It has no backup system.

  • $\begingroup$ Don't think this answers the stated question, which is what "answer" posts are expected to do. If you have a new question, please ask it in a new thread. $\endgroup$
    – Ralph J
    Commented May 24, 2019 at 13:11
  • $\begingroup$ Hello solomon, welcome to aviation.stackexchange. Please don"t ask followup question in the answers, instead you can ask a new question. $\endgroup$
    – DeltaLima
    Commented Jul 11, 2019 at 21:14

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