FADEC

[Just an Engineer]

Coming back to the original topic, the answer is: depending on type. While most aircraft with FADEC engines do stop if both channels are dead, I know of at least one aircraft, the Avro RJ series, where they have one FADEC and one backup mode.

Not sure you could call the RJ a proper FADEC though ?

Intelligent ECU/EEC maybe. It's a bit of a hybrid as it was basically an upgraded mechanical linkage system from the 146 done on the cheap

Why does that not surprise me from BAe

[DOJETDRIVER]

It's been a while. But I thought the FRJ the engine would continue to work even if BOTH channels failed. I could be wrong, but I thought it had something like a "manual reversion".


On the ERJ, if the FADECs go, so does the engine.

[Wing Root]

Full ATSB Report on a 717 that had a FADEC failure followed by shutdown

The crew of the Boeing 717-200 aircraft reported that during the climb from Launceston airport, while passing 7,000 ft above sea level, the right engine sustained an uncommanded in-flight shutdown.

The right engine EEC sustained a failure of both channels of an independent two-channel system, resulting in an in-flight engine shutdown with no prior indications to the flight crew.

[VnV2178B]

There is a huge amount of testing at lots of levels before any flight software is released - I know, it's kept me in work for twenty years! - most of it is done at the vendor's site but the integration/systems/acceptance is done at the customer's. Many eyes look over each step, independent test and design teams to try to achieve objectivity.

VnV

[lomapaseo]

Quote:
Actually the FADEC can override the pilot if it decides a command is wrong in a given set of circumstances

Could you give an example please?

The FADEC doesn't judge the pilots action as right or wrong. It ensures that the engine runs without damaging itself while at the same time judging the validity of the inputs from anywhere in the system. If the pilot provides a valid input the FADEC will follow. However if an engine limit is reached the FADEC will react to protect the engine (typically by metering fuel to achieve the last commanded thrust).

However in the case of a redline exceedance the FADECD may latch at idle and not respond futher unless all power to mit is reset.

Your mileage may vary so please consult the individual manuals

[Just an Engineer]

I don't think that there would be a software download just before a flight.

There is a huge amount of testing at lots of levels before any flight software is released - I know, it's kept me in work for twenty years! - most of it is done at the vendor's site but the integration/systems/acceptance is done at the customer's. Many eyes look over each step, independent test and design teams to try to achieve objectivity.

Presumably we are talking about things from a different perspective here.

In the inital testing or when revising any software then there would be software testing/integration/acceptance with the customer which in this case it would be the aircraft manafacturer

Once any software is finalised in the FADEC and delivered to the Airline however it should be relatively plug and play even if you are just replacing the FADEC's for a software revision.

[Golden Rivet]

"To be a true, 100%, Full Authority Digital Engine Control, there must not be any form of manual override available.

False - the fire handles are hard wired through to the fuel control unit.

[Just an Engineer]

"To be a true, 100%, Full Authority Digital Engine Control, there must not be any form of manual override available.


False - the fire handles are hard wired through to the fuel control unit.

Probabally agree (?) with your statement as it stands however you were a wee bit selective in your cut and paste

Full quote reads.....

"To be a true, 100%, Full Authority Digital Engine Control, there must not be any form of manual override available. This literally places full authority to the operating parameters of the engine in the hands of the computer. If a total FADEC failure occurs, the engine fails."

I think the key words here are operating parameters i.e normal operation not emergency.

[VnV2178B]

JaE,

The provision of software and its download are two separate items.

Yes, once it has been build, tested and delivered it's fairly simple to put it into the FADEC - the 777 has an 'on-wing' facility which enables the software to be updated without taking the FADEC off the aircraft and swapping the computer cards. Even so, it's still a shop job, not the kind of thing that you do on a whim, and also the frequency of updates is very slow, we are talking of one every several years not daily like a PC!

I did try to find out when there was a release of new software for the T800 but it seems to have been some years back!.

VnV

[monkey_wrench]

VnV2178B

Software updates don't always require the FADEC to come off wing. The CFM engine on the 737NG for example can receive software updates very easily on wing. After completion, no engine run is required and of course both FADEC's have to be updated at the same time in order to maintain software commonality. This is the one occasion which breaks the "don't do work on both engines at the same time rule"...

[VnV2178B]

I agree again, it's not always the case that the FADEC has to come off wing for new software - I did say that that's true for the B777/Trent800 (and I assume the same for the other engine options - I only have experience of R-Rs in this case). Earlier versions (RB211 for 747 and T700 for Airbus) needed to have the FADEC/FAFC off-wing and a card reprogram. I assume also that the newer aircraft will also specify on-wing downloads. I just wanted to make the point that you don't change a FADEC software by logging into Microsoft update and pressing OK, at least not yet...

VnV

[MidgetBoy]

I just had a 172 equipped with a diesel engine running on FADEC and it is true that if you lose battery power that your engine dies. There's nothing you can do. To my knowledge all you can do is choose which computer to use and that's about it.

[Just an Engineer]

Software updates don't always require the FADEC to come off wing. The CFM engine on the 737NG for example can receive software updates very easily on wing. After completion, no engine run is required and of course both FADEC's have to be updated at the same time in order to maintain software commonality.

Even I am suprised at that one

I would have thought at least a ground idle run would be required even if its just to check for any generated faults. Would have thought some defects will only manifest themselves on a running engine.