Quoting transaeroyyz (Reply 45): This is what it probably looked like, quite concerning that this is still happening years later!

Firstly, in the incident pic you linked, the engine was not a GE-90 but a RR Trent 800. Secondly, the MH incident had nothing to do with the RR engine and was caused by delamination of the D-Duct which I believe is a Boeing part.

http://www.flightglobal.com/news/art...sian-boeing-777-200er-over-210474/

Quoting imiakhtar (Reply 50): Secondly, the MH incident had nothing to do with the RR engine and was caused by delamination of the D-Duct which I believe is a Boeing part.

Correct. There was some collateral damage to the jet pipe, but it was caused by the failure of the Boeing D Duct.

Quoting Tristarsteve (Reply 49): No need to ground the aircraft for investigation.

And on the MH D Duct., I called out the local Swedish accident investigators, but after a good look around they declared that they were not interested.

Looking at the Avherald website it seems that the a/c involved is C-FITW.... it's quite funny to note that, excluding the last letter, this is definitely not an encouraging registration for an a/c!  

Any how for those that haven't seen any pic yet, Here is one I snap as I was busy recording .

Quoting 777 (Reply 52): Looking at the Avherald website it seems that the a/c involved is C-FITW.... it's quite funny to note that, excluding the last letter, this is definitely not an encouraging registration for an a/c!

AC's 1st 3 77Ws are in the same registration series... 1st was C-FITL, the 2nd is worse I would say   ... C-FITU:


View Large View Medium

Photo © Allen Zhao


I drove by the scene this morning. Besides a few news vans around the gas station nothing much was going on I could see. I go through there everyday almost to/from work.

Quoting Tristarsteve (Reply 51): And on the MH D Duct., I called out the local Swedish accident investigators, but after a good look around they declared that they were not interested.

I find that quite surprising considering the incident at ARN happened more than a year after the FAA issue an AD. Have there been any service bulletins to address the issue?

Quoting Tristarsteve (Reply 49): No need to ground the aircraft for investigation. Youve got the broken engine in the hangar to look at.

After the filters are pulled, fuel sampled, software logs dowloaded, etc. That ends up taking a few days. This is standard for an engine failure as there are aspects of the airplane that could lead to the failure. Its not good enough to fix the problem, the issue must be understood. Its quite possible contaminated fuel was the culprit or if not the root cause a contributor. It won't take long to release the airframe, but it does have to be grounded until the aircraft subsystems that impact the engine are investigated.

It was also an uncontained failure. Did any parts hit the airframe? Even if there was no part impact on the airframe, the failure might have been an event that could damage the pylon. There is more than a little inspection ahead for C-FITW.

Lightsaber

Quoting lightsaber (Reply 19): The engine should already be on its way (if not half way to on the wing) with a new nacelle. The will need to pull fuel filters and sample aircraft fuel. The rest will be pulled and inspected off aircraft. The issue is the holiday weekend. Unless aircraft structure was damaged, the aircraft should fly within a week. The engine? It will be torn apart and studied in detail for a long time. Someone owes AC a new engine... even if its AC itself.

Excuse my ignorance, and I know AC doesn't have many B777s in their fleet, but wouldn't they have access to a spare engine somewhere? For this very reason? If not, isn't that kind of a risk? I know the GE90s are usually very reliable but they do require servicing. I was once told that an engine usually sits on a aircraft for an average of 3-5 years before it is replaced, so most airlines have functioning spare engines ready to be swapped.
Assuming there is no structural damage to the wing or airframe, this aircraft should be back in service within a week if they access to an engine. Time is money.

Quoting 777 (Reply 52): Looking at the Avherald website it seems that the a/c involved is C-FITW.... it's quite funny to note that, excluding the last letter, this is definitely not an encouraging registration for an a/c!

I noticed that too - why on Earth would they have chosen such awful letters? Granted, most people outside of the industry wouldn't know what CFIT stands for but I'm pretty sure all pilots know!

Is it possible to take the 777s off the non-essential routes like LHR and FRA (replacing them with 767s and A330s) in order to deploy them on the Asian flights?

What was the registration of the 777 that experienced this engine failure?

Quoting par13del (Reply 12): To us non-techies, uncontained failure does that mean not contained within the engine or a puncture of the fuselage?

A uncontained failure would consist of parts(which usually are the rotating parts) of the engine which come through the Fan or Engine case. Going out the tailpipe is a contained failure, even though there might be more debris than in a uncontained failure. This is why most large Fans now have kevlar wraps around the Fan Case, it is a lightweight solution to help contain fan blades from piercing the fan case. Lots of energy there. Otherwise, the fan cases would be too heavy without the kevlar wraps.

In the core engine, there is not as much energy. One of the big problems would be if a turbine disk let go. That's a lot of energy there, not so much in individual turbine blades relative to the fan.

Quoting B757forever (Reply 14): My understanding has always been that an uncontained failure would describe a situation in which parts exited the engine by puncturing through the engine case or containment ring. True uncontained failures are rare. I suspect when the analysis is done, this AC incident will be declared a contained failure, as the parts most likely exited the tailpipe.

  

Quoting lightsaber (Reply 19): Any parts that go out the nozzles are a 'contained failure.'

  

Quoting connies4ever (Reply 10): My initial impression was a turbine blade or blades, likely from the HP turbine, got shed and exited the back end. GE90s I believe have passed the goose test.

They don't test with geese - but with smaller birds.

Quoting B757forever (Reply 14): My understanding has always been that an uncontained failure would describe a situation in which parts exited the engine by puncturing through the engine case or containment ring. True uncontained failures are rare. I suspect when the analysis is done, this AC incident will be declared a contained failure, as the parts most likely exited the tailpipe.

If items shed out the back - it is contained. But - as is noted, we don't have data yet.

Quoting ltbewr (Reply 20): Of course one has to wonder how this major failure happened. Could bird ingestion be a factor or is this some mx or original part flaw that was missed?

Yes. Yes. Yes.

Quoting connies4ever (Reply 41): Not sure how many are available, then there's the cabin config issue. Do you make them like the 3 'orphans' that don't have J class ? Or spend the money and time to XM them ?

I'm sure if they needed them bad enough, some could be found. Well if it's only a short term thing, then they probably wouldn't bother with the XM cabin, but if it was a long term (5+ years) then I suspect they would take the time to make them match the rest of the fleet, saves many headaches down the road. Nothing worse then having to tell a super elite his suite is now just a seat  

Quoting N5716B (Reply 44): Honestly, I wonder how some of those intrepid reporters actually manage to get out of bed successfully.

Thanks for the laugh, and yes we have our share of "reporters" that are often too smart for their own good.

Quoting kl692 (Reply 47): Is this right? if so couldn't have been that much a problem

No that's definitely not correct. AC definitely does not fly SYD to HKG, a/c is still in the hanger, and will be for some time.

Quoting lightsaber (Reply 56): There is more than a little inspection ahead for C-FITW.

  

Quoting richierich (Reply 57): Assuming there is no structural damage to the wing or airframe, this aircraft should be back in service within a week if they access to an engine. Time is money.

In a perfect world, yes, but modern airplanes are incredibly complex machines. I'm not an expert on this, but I'm sure someone on here will be able to fill us on on the multitude of tests that are required before it can take to the air again. Better to err on the side of caution then to rush a ~ $300 million investment into the air.

Quoting JAGflyer (Reply 58): Is it possible to take the 777s off the non-essential routes like LHR and FRA (replacing them with 767s and A330s) in order to deploy them on the Asian flights?

I don't think I would call LHR & FRA non-essential routes   In terms of demand, right now it would be easier to sub a 767 in for the asia routes, as they are not running near as full as LHR or FRA, and could take the 767 with a minimal amount of disruption.

Quoting Pelle (Reply 59): What was the registration of the 777 that experienced this engine failure?

C-FITW, Fin #733

Quoting ANM604 (Reply 62): In a perfect world, yes, but modern airplanes are incredibly complex machines. I'm not an expert on this, but I'm sure someone on here will be able to fill us on on the multitude of tests that are required before it can take to the air again.

Either some of you know a lot more about this than you are saying, or you are making it up.
An engine has failed, it will be changed.
If no other damage has occured, this will take 10 hrs or so, if the spare engine is on site.

When you fit a new engine, it needs a leak check. Takes about 20 mins.

Quoting lightsaber (Reply 56): fter the filters are pulled, fuel sampled, software logs dowloaded, etc. That ends up taking a few days. This is standard for an engine failure as there are aspects of the airplane that could lead to the failure

When I started on the L1011 in 1976 in BAH, we had an engine failure every week. The engines had a hard life of 1200 cycles, which they never achieved. We changed at least one engine a week. If every engine change took a few days, we would have no aircraft left.
My record was in the hangar at 1400, engine changed and back on the ramp at 1900, departed at 2050.

I may be the only person on this site who cares about this, but Japanese voice actress Yuu Asakawa was on this flight, returning to Japan after attending the Anime North convention in Toronto. Her Twitter account has a few pictures of the fuel dump and emergency vehicles.

Quoting connies4ever (Reply 41): Not sure how many are available, then there's the cabin config issue. Do you make them like the 3 'orphans' that don't have J class ? Or spend the money and time to XM them ?

Off topic, but do you know if the 3 non-xm'd 763 are staying for a while? I have friends going to BCN who are very disappointed about not getting IFE's.

According to avhearld, the FADEC shut down the engine automatically due to the EGT increase. Anyone know at what temp the FADEC starts to shut-down the engine?

KrisYYZ

Quoting krisyyz (Reply 65): Off topic, but do you know if the 3 non-xm'd 763 are staying for a while? I have friends going to BCN who are very disappointed about not getting IFE's.

I'd say these 3 are bound for the LCC, which is coming whether some embrace it or not.

Looks like 733 is planned for AC001/31MAY, so back in the air Thursday afternoon.

[Edited 2012-05-29 15:55:02]

Quoting richierich (Reply 57): I know AC doesn't have many B777s in their fleet

Quoting JAAlbert (Reply 29): Quoting Viscount724 (Reply 26): AC had 2 77Ws divert to Alaska on flights to Asia (one to Fairbanks in 2008 and one to Anchorage in 2009). Both required an engine change and the engines had to be trucked to Alaska. The one for the 77W in FAI came all the way from YYZ, a road trip of about 4,000 miles that took about a week. Both aircraft were out of service for about 2 weeks. Did they also have to truck in equipment needed to change the engine?

News items at the time said the necessary equipment for the engine change was shipped with the engine.

Quoting connies4ever (Reply 66): I'd say these 3 are bound for the LCC, which is coming whether some embrace it or not.

The plan for the LWC, (it will NOT be a LCC), is for even more seats in the B763. There is talk of 2x4x2 in Y, and a Y+ of 2x2x2. In other words, "you wanted a cheap seat ... there it is". The start up is for 5 B763s.

Quoting krisyyz (Reply 65): Off topic, but do you know if the 3 non-xm'd 763 are staying for a while? I have friends going to BCN who are very disappointed about not getting IFE's.

BCN is a very low yield market, and the low yield B763s are placed on it for that reason. So unless there is a last minute equipment change, the only IFE will be the overhead screens.

[Edited 2012-05-29 16:48:29]

Quoting connies4ever (Reply 66): I'd say these 3 are bound for the LCC, which is coming whether some embrace it or not.

Quoting longhauler (Reply 69): BCN is a very low yeild market, and the low yield B763s are placed on it for that reason. So unless there is a last minute equipment change, the only IFE will be the overhead screens.

Thanks for the info!

Not sure if AC is planning long-haul LCC, but by the sounds of it BCN would make a good LCC destination.

In the B77L thread, some have suggested that IF AC takes AI 's 77Ls, they could be configured for LCC ops, any chance of that? Isn't the 77L to heavy and basically the wrong aircraft for LCC ops?

KrisYYZ

[Edited 2012-05-29 16:53:17]

Quoting krisyyz (Reply 65): According to avhearld, the FADEC shut down the engine automatically due to the EGT increase. Anyone know at what temp the FADEC starts to shut-down the engine?

I thought FADEC would never ever shut down an engine. Crew have to do it themselves regardless of engine condition.

Quoting Tristarsteve (Reply 63): If no other damage has occured, this will take 10 hrs or so, if the spare engine is on site. When you fit a new engine, it needs a leak check. Takes about 20 mins.

Besides the spare engine, another engine dolly and a set of hoist or some other engine lifting tools.

If it's like most engine changes, have to take her out for a acceleration check, power assurance run too.

Quoting HNLPointShoot (Reply 64): I may be the only person on this site who cares about this, but Japanese voice actress Yuu Asakawa was on this flight, returning to Japan after attending the Anime North convention in Toronto. Her Twitter account has a few pictures of the fuel dump and emergency vehicles.

When you talk about a failure like this, and add it up with all the other 'crap' going on at AC right now, and combine it with the comment I found on Yuu Asakawa's twitter account (below), this goes to show you why people view *some* airlines as complete failures in customer service....

From her twitter:

Yuu Asakawa ‏@Julia320

But in spite of the trouble,some female staff members at the service Counter of Air Canada are so obnoxious and rude. Speechless.

---------------------------

Hence why more and more of my friends and family continue to shuffle across the border to fly on JetBlue, or fly on WestJet.

A failure of an airline to achieve the desired results of delivering on their promise to get you from A to B on X day AND their subsequent handling of the aftermath are a direct measure of the health of an airline, and.. really, can be applied to any business.

I'm glad that the plane made it back safely, no one was hurt, but these large airlines need to really get their act together on how they treat the people AFTER a 'failure to deliver' occurs.

1011

Quoting jporterfi (Reply 39): I don't mean to sound like a noob, but how could you tell that it was a compressor and not a turbine blade?

From the blade, you can tell because turbine blade will show signs of very high temps (once it's been used), the compressor blades won't. But from the photo posted in reply 8, it's a (brand-new) compressor. Turbines have fewer stages and the diameter of the rotor increases with each stage. Compressors have more stages and the diameter of the rotor stays the same for most of it, but the diameter of the central disks increase, leading to constant volume as the flow is compressed.

A picture of a GE-90 turbine (and a 6' man for scale) is shown at this link: http://www.flickr.com/photos/gereports/5387761739/

You can see that each stage has a markedly different diameter than the stage before it.

Quoting richierich (Reply 57): but wouldn't they have access to a spare engine somewhere?

Yes. But where? When KLM had a GE-90-115 fail, their one spare was in AMS when the plane was in South Africa. With AC's small (and diverse) 777 fleet, they might 'lease' a spare engine from GE most likely kept at Schenectady or another GE location. Since each GE-90-115 is worth ~$15 million, they aren't sent out the door without proper paper. That takes a few hours. Also, the proceedures for an uncontained failure must be 'made available' (does AC work to paper or paperless?) from Boeing and GE too. (I'm sure they are standard inspection paper pressed into service to look for damage.)

Quoting Tristarsteve (Reply 63): When I started on the L1011 in 1976

You do realize, due to numerous crashes and ETOPS, the rules have changed in 36 years? One has to prove far better reliability than what was accepted back then before an aircraft is ETOPS certified. Also terminology has changed. Many of the RB211s you pulled would have had defects and not failures in today's jargon. Its ok today to pull an engine for a defect (which might be an upcoming failure with a known remaining life). Pulling an engine for a failure is a far bigger deal for both the engine vendor and the airline.

Quoting Tristarsteve (Reply 63): We changed at least one engine a week. If every engine change took a few days, we would have no aircraft left.

I'm not implying for every engine change. I'm discussing an uncontained failure under ETOPS rules. Heck, in the late 1990s the rules changed for multi-engine aircraft after Pratt put a third of a rotor through a mom and child. For an engine being pulled for a malfunction, defect, uncertain boroscope inspection (or for it), it can be done in hours.

But under today's ETOPS rules, engine issues as you describe would thankfully result in a grounded fleet. A GE and the above mentioned Pratt rotor failure happened almost back to back and that changed the regulations. The fact AC has had three GE-90 failures will result in a nice little six sigma study to figure out what they are doing wrong; three failures over the years!

Quoting bartonsayswhat (Reply 67): Looks like 733 is planned for AC001/31MAY, so back in the air Thursday afternoon

Which makes my part of the discussion moot. It looks like AC had the proceedures on hand and the engine too (or cloes by). Good to hear.

Quoting Tristarsteve (Reply 63): Either some of you know a lot more about this than you are saying, or you are making it up. When you fit a new engine, it needs a leak check. Takes about 20 mins.

While I was only a child back then, I find it tough to believe an uncontained failure had no investigation back then.

For a normal engine change, that is true. If AC plays that fast and loose after an uncontained failure... I doubt it. Other inspections must happen. It doesn't take that long. It can be done in 48 hours and it looks like AC won't take too much longer than that. Again, there is a big difference between defective engine and a "failure." Failures *must* be reported to the appropriate aviation authorities and woe to the airline that lacks proof they did the follow up correctly. It can result in a warning or even loss of ETOPS privileges.

Seriously, when I was at Pratt after an engine failure we received the fuel filter with some sample fuel, the oil filter with oil to be sampled, the FADAC logs, black box logs (both cockpit voice and data), photos of the airframe plus the engine, and the engine for discection. I somehow doubt AC would be lax and put their ETOPS cert at risk.



Lightsaber

Quoting ltbewr (Reply 20): Of course one has to wonder how this major failure happened.

Too early to tell, but contained failures are statistically unavoidable.

Quoting ltbewr (Reply 20): Could bird ingestion be a factor or is this some mx or original part flaw that was missed?

Yes and yes, and maybe neither.

Quoting ltbewr (Reply 20): I also wonder if their is some flaw in this GE engine series as there has been several major engine failures of them used on 777's.

Unlikely; the reliability of engines is most typically measured in In-Flight Shutdowns (IFSD's) per 100,000 flight hours. Given the number of GE90's in service and the rate they rack up hours, it takes many events to make a statistical blip. Some number of failures is normal and expected; this engine appears to have done exactly what it was supposed to when faced with a blade failure.

Quoting cv990coronado (Reply 35): Does this have any effect on AC's ETOPs rating for their 777's?

Not by default, unless TC decides they want to do something. Most ETOPS-rated engines run so far below the threshold IFSD requirements that any one failure doesn't make any difference.

Quoting jporterfi (Reply 39): I don't mean to sound like a noob, but how could you tell that it was a compressor and not a turbine blade?

In general, compressor blades are light, thin, and don't look like they've been blasted with a blowtorch. Turbine blades are the opposite.

Quoting abnormal (Reply 71): I thought FADEC would never ever shut down an engine

A FADEC will generally never actually give a shutdown command on its own; however, it will implement protections which may end up with the engine not getting enough fuel to stay running, in which case it shuts down by default.

Quoting abnormal (Reply 71): Crew have to do it themselves regardless of engine condition.

Crew can do it at any time; the FADEC will not intentionally allow a catastrophic engine condition to occur and, if shutdown is required to reach that goal, it will do so. The FADEC will try to keep the engine running as long as it can.

Tom.

Quoting longhauler (Reply 69): Quoting krisyyz (Reply 65): Off topic, but do you know if the 3 non-xm'd 763 are staying for a while? I have friends going to BCN who are very disappointed about not getting IFE's. BCN is a very low yield market, and the low yield B763s are placed on it for that reason. So unless there is a last minute equipment change, the only IFE will be the overhead screens.

BCN and ATH are really only served due to their being 'home ports' for many cruise ships in the Med. Serving these destinations permits AC Holidays to provide a total package for cruise ship pax.

Given the likelihood of Greece having extended financial problems, it will be interesting to see if AC continue to serve ATH.

If anyone saw the ABC or CNN coverage of this incident they focused on "can a plane continue take-off with just one engine?" Uhh, yes it can, it isnt a question, it absolutely can. But the reporting suggested that it just might not make it on one engine and that it was just almost a giant disaster. They also ran repeated video of an AC A320 taking off and a 767-300 landing. ABC did have an animation of a 777 but otherwise it was all the wrong plane. They also defined what happened as "uncontained" which I think we all now see was not the case as it appears the debris exited the tailpipe and not through the engine casing.

Quoting tdscanuck (Reply 76): A FADEC will generally never actually give a shutdown command on its own; however, it will implement protections which may end up with the engine not getting enough fuel to stay running, in which case it shuts down by default.

Quoting tdscanuck (Reply 76): Crew can do it at any time; the FADEC will not intentionally allow a catastrophic engine condition to occur and, if shutdown is required to reach that goal, it will do so. The FADEC will try to keep the engine running as long as it ca

That makes sense, I appreciate the info.

Quoting connies4ever (Reply 77): BCN and ATH are really only served due to their being 'home ports' for many cruise ships in the Med. Serving these destinations permits AC Holidays to provide a total package for cruise ship pax. Given the likelihood of Greece having extended financial problems, it will be interesting to see if AC continue to serve ATH.

Thanks again. I was thinking the same thing about Greece, it would be interesting to know what the mix is on the ATH flight, AC holiday pax vs. VFR pax who flew OA in the past. I miss seeing the OA A343 at YYZ.

KrisYYZ

Quoting woodsboy (Reply 78): They also defined what happened as "uncontained" which I think we all now see was not the case as it appears the debris exited the tailpipe and not through the engine casing.

Do we have accounts of anybody who has set eyes on the cowling to confirm this?

Quoting tdscanuck (Reply 76): A FADEC will generally never actually give a shutdown command on its own; however, it will implement protections which may end up with the engine not getting enough fuel to stay running, in which case it shuts down by default.

Follow up question: Are the FADEC's aware of each other, i.e if one engine is shutdown will the other FADEC alter its operations / parameters in any way

Quoting woodsboy (Reply 78): If anyone saw the ABC or CNN coverage of this incident they focused on "can a plane continue take-off with just one engine?" Uhh, yes it can, it isnt a question, it absolutely can.

Not only can the 777 do it, but it's specifically designed and certified to.

Quoting jporterfi (Reply 39): I don't mean to sound like a noob, but how could you tell that it was a compressor and not a turbine blade?

Here's the best nutshell "how do you tell" answer.

Quoting tdscanuck (Reply 76): In general, compressor blades are light, thin, and don't look like they've been blasted with a blowtorch. Turbine blades are the opposite.

Sorry for the delay. If you (jporterfi) have any additional questions, I'll be happy to answer them (if tdscanuck or lightsaber don't get back to you first).

Quoting krisyyz (Reply 70): Not sure if AC is planning long-haul LCC, but by the sounds of it BCN would make a good LCC destination. In the B77L thread, some have suggested that IF AC takes AI 's 77Ls, they could be configured for LCC ops, any chance of that? Isn't the 77L to heavy and basically the wrong aircraft for LCC ops?

BCN has been served by AC using the non-XM'ed 767's since the summer of 2010 (I believe), so in some sense they have already been serving it in LCC/LWC ops. Yes they could configure the 77LR's for the start-up, and yes, it is not the greatest a/c for the routes it would likely be used on.

Quoting lnglive1011yyz (Reply 73): I'm glad that the plane made it back safely, no one was hurt, but these large airlines need to really get their act together on how they treat the people AFTER a 'failure to deliver' occurs.

I see what you're saying, but unless we were there, it's really hard to judge how an airline handled a situation from one persons tweet. It really isn't that credible. Granted that in an ideal situation passengers shouldn't be complaining, but in reality, there will ALWAYS be someone who cannot be pleased. It's just human nature.

Quoting lightsaber (Reply 75):

Great post, thanks.

Quoting BoeingVista (Reply 80): Are the FADEC's aware of each other, i.e if one engine is shutdown will the other FADEC alter its operations / parameters in any way

I don't think the FADEC's talk directly to each other; that would open a up a whole potential can of worms where a failing FADEC could influence the good engine and that's contrary to most propulsion design practices.

The FADEC's do talk to the airplane and the airplane can alter commands to each engine independently. As a result, if an engine fails, the airplane may ask the running engine's FADEC to do something different but I don't think the other FADEC knows why it's being asked.

For example, in large twins at low weight and high thrust you can get below Vmca during an engine failure if you're not careful; the airplane may reduce thrust on the running engine (you're light so you still have the required climb performance) to maintain acceptable margin to Vmca.

Tom.

Quoting DocLightning (Reply 74): A picture of a GE-90 turbine (and a 6' man for scale) is shown at this link: http://www.flickr.com/photos/gereports/5387761739/ You can see that each stage has a markedly different diameter than the stage before it.

That picture is of an industrial gas turbine at GE Schenectady. Not a GE90.

Quoting BoeingVista (Reply 80): Follow up question: Are the FADEC's aware of each other, i.e if one engine is shutdown will the other FADEC alter its operations / parameters in any way

The FADEC for each engine implements the thrust demand of the pilot or the airplane, for that engine only. The FADEC does not demand thrust, it schedules the engine parameters (N1, fuel, VSV position) in response to a demand. If one engine is shut down the other FADEC is unaware, it is up to the pilot or airplane to demand more thrust if appropriate from the other engine.

Quoting tdscanuck (Reply 84): I don't think the FADEC's talk directly to each other; that would open a up a whole potential can of worms where a failing FADEC could influence the good engine and that's contrary to most propulsion design practices.

Quoting gasturbineengr (Reply 85): The FADEC for each engine implements the thrust demand of the pilot or the airplane, for that engine only. The FADEC does not demand thrust, it schedules the engine parameters (N1, fuel, VSV position) in response to a demand.

I hear you both, the scenario that I had in mind though is that a FADEC will try to protect the engine and as mentioned above this kind of protection may lead to an inadvertent shutdown, now this would be a minor inconvenience if the other engine is still turning but if it isn't it would make sense for the FADEC on the operational engine to suck it up and allow the potential damage to occur (as long as it wasn't about to throw blades).

I understand that designing this control feature in could be problematic for a whole host of reasons but as my job involves coming up with outlandish failure scenarios in interdependent systems and seeing what can be done to mitigate risk this scenario occurred to me.

I also find it amusing how the big news today is that the plane had two previous incidents - an APU fire and a goose ingestion in 2009 - years ago!

http://www.cbc.ca/news/canada/toront...29/falling-debris-aircraft546.html

Some of the comments on the article are also pretty funny...

[Edited 2012-05-30 10:27:33]

Quoting tdscanuck (Reply 76): The FADEC will try to keep the engine running as long as it can.

   A windmilling engine is drag. A FADAC even has the option to run the engine in a 'criple mode.' Now, I do not know the GE-90 specifics, but typically it will give information to the pilots if the engine can turn on the fuel burn impact and available thrust.

Quoting tdscanuck (Reply 76): Unlikely; the reliability of engines is most typically measured in In-Flight Shutdowns (IFSD's) per 100,000 flight hours. Given the number of GE90's in service and the rate they rack up hours, it takes many events to make a statistical blip.

Quoting tdscanuck (Reply 84): The FADEC's do talk to the airplane and the airplane can alter commands to each engine independently. As a result, if an engine fails, the airplane may ask the running engine's FADEC to do something different but I don't think the other FADEC knows why it's being asked.

   It also provides the airframe with information for subsystems. (e.g,. try to predict filter icing before it is an issue and have the airframe react as needed to keep the engines turning).

Quoting gasturbineengr (Reply 85): The FADEC does not demand thrust, it schedules the engine parameters (N1, fuel, VSV position) in response to a demand.

   But if one engine is having issues, the FADAC will receive airframe information and certain 'maps' change. For example, there are codes that will tell a FADAC the other engine is having issues. Thus the FADAC might be in a regime where if both engines are running well the ignitor is off but if either is having issues the ignitor is turned on, damn the maintenance bill.  

Quoting BoeingVista (Reply 86): the scenario that I had in mind though is that a FADEC will try to protect the engine and as mentioned above this kind of protection may lead to an inadvertent shutdown

Only if it is a catestrophic failure will the FADAC shut the engine down typically. Again, I do not know the 777, but on the A330, the final call is made by the airframe's computers/pilots. The FADAC calculates damage. It tries to minimize the damage. But I have gone through engine logs where the FADAC kept the engine going to the extreme margins as the airframe computers/pilot would not give permission for an engine shutdown.

In that case, the FADAC does what it can: extreme stator settings, ignitor, cut turbine casing cooling to open up tip gaps, even startup fuel flow (some engines will flow more fuel to the bottom two injectors for engine ignition), starting the spark ignitor, allowing turbine inlet temperature to climb into the yellow, run with overheating oil, run with insufficient oil, etc. Some of those settings are done to boost fuel flow for a commanded thrust setting to keep the engine lit (stable thrust). Others to accommodate a defect by allowing a tremendous increase in engine wear. That increased wear scenario sets the diversion limits (with a potential ETOPS impact).

The FADAC will only stop an engine when parameters go past the abort limits (temperature, pressures, vibration, bearing pressure, oil conditions, etc.) Shutting down an engine usually takes pilot command. (Not always, I have seen airframe commended shutdowns and FADAC commanded shutdowns, but they are extremely rare.) The newer FADACs will keep the engine going through engine, pylon, and even wing damaging conditions! But it will demand the aircraft send out a message for the appropriate inspections. (e.g., if engine vibration is so high that the pylon must be inspected during an engine replacement.)

Lightsaber

Quoting lightsaber (Reply 88):

Lightsaber, appreciate the in-depth explanation.

ATLengineer

Quoting BoeingVista (Reply 86): now this would be a minor inconvenience if the other engine is still turning but if it isn't it would make sense for the FADEC on the operational engine to suck it up and allow the potential damage to occur (as long as it wasn't about to throw blades).

I've only ever seen a FADEC actually shut down an engine when it was headed for "throw blades" territory (or the FADEC thought it was). As lightsaber beautifully described, it will do it's darnedest to keep the engine running, even at the expense of massive economic damage. It will only actually end up with a shutdown when the alternative is the engine coming apart.

Tom.

This happened to a Malaysia Airlines 777-200ER with RR engine from a couple of years ago. I imagine something similar happened this time.


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Photo © Fredrik Granberg

Quoting Tristarsteve (Reply 63): Either some of you know a lot more about this than you are saying, or you are making it up.

Tristar Steve - love the post! Nice to an expert on board.

Quoting longhauler (Reply 69): The plan for the LWC, (it will NOT be a LCC)

Sorry, OT. But what is the 'W' in LWC?

Quoting SP90 (Reply 91): This happened to a Malaysia Airlines 777-200ER with RR engine from a couple of years ago. I imagine something similar happened this time.

The MH was an engine cowling failure. The engine ran throughout the incident.
We changed the D duct and the B777 flew home.

Quoting imiakhtar (Reply 50): Firstly, in the incident pic you linked, the engine was not a GE-90 but a RR Trent 800. Secondly, the MH incident had nothing to do with the RR engine and was caused by delamination of the D-Duct which I believe is a Boeing part. http://www.flightglobal.com/news/art...0474/

Read the flight article. I was the maint worker at ARN. I had to e mail Flight as they had got it so wrong at first.

Quoting golfradio (Reply 93): Sorry, OT. But what is the 'W' in LWC?

The planned leisure carrier will be a Low Wage Carrier, not a Low Cost Carrier. As long as the same management runs it, and as long as they keep giving themselves huge raises and bonuses, it will never be a LCC.