FADEC

[captmu2]

Hello everyone again,

I would like to gain any information that anyone may have on the function of FADEC. Function may not be the right way of posting my question...so we can start with the principles and how they work...after the basics I will likely be enlightened.

Thanks in advance for your input, helping increase my base of Aviation knowledge.

[HPSOV]

I dont know about the technical aspects of the FADEC system, but from a pilots point of view there isn't much difference.
Basically instead of using the steel cable from the throttles to the engine it uses wires (sort of fly-by-wire I guess).
They system is better able to optimise engine efficiency giving a fuel saving of 0.5-1.0% over an EEC.
Another added benifit is that if the thrust levers are in the same position the system will command both engines to generate the same thrust, so no more staggered thrust levers!

[SKYYACHT]

FADEC is a sophisticated system that controls the engine parameters by digital signals generated by a Control unit. In essence, and in a simplified form, the FADEC communicates via computer to the Flight Management systems, and will command the thrust output to deliver the correct power for the current mode of flight. During engine start a FADEC system will monitor critical engine parameters such as EGT and N1 N2 etc. In modern FBW types such as A320 and B777, the system will operate in an active way, and will shut down engines and abort the start sequence if any abnormalities or parameter exceedences occur.
Hope that helps.

Tailwinds

:) :)

[3 putt]

With a view to getting more info on the subject,I see transair pilot shop have the books "Jet engines","The jet engine" and "Thrust for flight".Anyone know if any of these books cover FADEC in detail?

[john du'pruyting]

The Jan 2001 issue of Rotor and Wing magazine has a reasonable article on FADEC.

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marmalade, I like marmalade

[DoctorA300]

Hi,
A Fadec Engine control system basically
consist of an Electronic Engines Controller
or EEC, and assosiated sensors. There is
really no ´Black Magic´ involved, as some of
my fellow engineers would have you belive,
the EEC recives all the same parameters as a
traditional Hydromechanical fuel control does
, it just recives them as electrical signals.
It then computes, just as the mechanical one,
the required amount of fuel and then operates
a small electical fuel metering valve. The
main reason for having a Fadec system, is
that because nearly all parameters are
signalled electrically, you can monitor
many more, thereby optimising your engine
control and fuel burn. As an illustration the
good old JT8D had 5 controlling inputs, all
mechanical or pneumatic, the V2500 has 22,
most of them electrical a few pneumatic and
only one mechanical (N2). A couple of added
benifits are that the EEC can ´Synthezise`
that is, calculate a parameter if the
affected sensor is inop. And finally it is
much easier to troubleshoot because the EEC
monitors all it´s own sensors.

[This message has been edited by DoctorA300 (edited 20 January 2001).]

[Flight Safety]

If you're familiar with the concept of computer controllers for auto engines, FADEC is the same basic idea with a jet engine. A group of sensors feeding the computer, and the computer calculating the appropriate fuel (and other parameters it can adjust) to get optimum fuel burn and emissions from the engine. Like the car computer, it can report problems in the form of codes, but the "codes" are reported "live" to the EICAS system in the airplane. Unlike the auto, the throttle is electronic instead of mechanical. FADEC also has the benefit of protecting the engine from overstress in that it prevents the pilot (or other circumstances) from causing excessive EGT, excessive N1 or N2 speeds etc. that can damage or shorten the service life of the engine.

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Safe flying to you...

[This message has been edited by Flight Safety (edited 20 January 2001).]