http://www.flightglobal.com/articles...tinued-flight-after-loud-bang.html

Synopsis: EK 777 had a loud bang and a number of engine-related error messages on t/o. Five hours later upon landing, inspection revealed significant damage to the #2 engine cowling and inboard fan duct.

Didn't see any posts on this. This is somewhat alarming. EK is usually considered a top-notch airline, with competent pilots and a modern fleet. Does anyone know anymore details about this incident? I'm not a pilot, but I can't imagine that continuing on after having this kind of issue at takeoff would be a good idea. Can any pilots weigh in on this?

Well, Based on what I read somewhere previously, the messages they got required no actions for the pilots to return to the airport. That was a conclusion which was written by a 777 pilot. He said that these messages were not a reason to turn back, and if the pilots decide to turn back they should have a reason for it. Apparently, these warning messages may have been considered minor. Thats what I concluded after reading the news post.

Quoting mgm414 (Reply 1): Well, Based on what I read somewhere previously, the messages they got required no actions for the pilots to return to the airport

The article said following one of the loud bangs on takeoff one of their EICAS messages was thrust asymmetry warning meaning the damaged engine was producing significantly less thrust than the good engine. Such an EICAS message following a loud bang *should* be cause to turn back, as the engine was obviously damaged.

Who is going to enforce any penalties? Russia? I would hope EK would do some internal investigations and if necessary suspend the PIC and FO on that flight until it is over. While this was not a life threating incident, the failure to consider that it could have became on means bad decisions were made.

One has to wonder if this had been from hitting large birds and if so, it could have been observed by others.

Seeing as EK is neither a US company nor did this flight touch US territory, what jurisdiction does the NTSB even have over this?

Quoting blink182 (Reply 4): Seeing as EK is neither a US company nor did this flight touch US territory, what jurisdiction does the NTSB even have over this?

The aircraft manufacturer is based in the US.

Quoting mgm414 (Reply 1): Based on what I read somewhere previously, the messages they got required no actions for the pilots to return to the airport.

I am certainly not a 777 pilot, but it seems very hard for me to believe that a loud bang followed by thrust asymmetry is not a reason to turn back, especially in a twin.

Quoting blink182 (Reply 4): Seeing as EK is neither a US company nor did this flight touch US territory, what jurisdiction does the NTSB even have over this?

Country of Manufacture is a party to the investigation

Quoting blink182 (Reply 4): Seeing as EK is neither a US company nor did this flight touch US territory, what jurisdiction does the NTSB even have over this?

The NTSB doesn't have "jurisdiction" over anything, really. It is quite common for other countries to invite the NTSB to participate in or review investigations as they are generally considered to be the most capable and experienced such entity in the world.

Reality is that they received Status alerts not master cautions or warnings over the problem. They must have diagnosed the problem along with company and tech over HF and come to the decision to carry on. If you really want an in depth debate check PPrune there's quite a ruckus going on over there about their decision, most pilots agree that they would have done the same. Needless to say, when you hear a bang but the engine keeps performing as expected and you have no warnings or cautions, and you're flying over land, its very unlikely you're going to land as a precaution just to check things out, this is the reality of airline flying these days. Pilots are more afraid of what the airline will do to them than what the plane might do. I believe this should be put under the heading of Calculated Risk.

BTW check post #44 http://www.pprune.org/middle-east/46...mirates-777-incident-moscow-3.html

[Edited 2011-09-03 06:49:04]

[Edited 2011-09-03 07:13:55]

Quoting 3rdGen (Reply 8): Pilots are more afraid of what the airline will do to them than the what the plane might do.

Therein lies the key fact.

Quoting blink182 (Reply 4): Seeing as EK is neither a US company nor did this flight touch US territory, what jurisdiction does the NTSB even have over this?

The NTSB is often asked to come in to help with investigations, they often go abroad to help with accident/incident investigations, however its only ever done at the request of the Country in charge of leading the investigation. Reality is not every country can afford a proper and full blown accident investigation team with the expertise, knowledge, and tools that the major ones, such as the NTSB, AAIB(UK) or others. Having these sorts of organizations are a luxury for countries not a necessity.

The developed nations have such a good accident investigation branches because of the large number of accidents that have taken place there simply due to the volume and the history of air travel in these nations. Expect to see India/Middle East/China start to have their own pretty soon, with more air travel/airplanes comes more accidents/incidents and therefore better teams of investigators.

[Edited 2011-09-03 07:36:27]

Quoting Transpac787 (Reply 2): The article said following one of the loud bangs on takeoff one of their EICAS messages was thrust asymmetry warning meaning the damaged engine was producing significantly less thrust than the good engine. Such an EICAS message following a loud bang *should* be cause to turn back, as the engine was obviously damaged.

Did the engine gauges show a significantly lower thrust available from that 'damaged' engine at that time? Did they show lower performance from the engine during the rest of the flight?

Such an EICAS message means check the actual gauges to verify any problems and determine the severity, the message alone does not justify turning back without validation from other instruments.

The key paragraph in the article is

Quote: The report does not discuss what procedures the Emirates crew followed after hearing the bang and receiving the AHM annunciations or whether the aircraft should have been returned to Domodedovo.

Quoting 3rdGen (Reply 8): but the engine keeps performing as expected

But it didnt because they got a thrust asymmetry warning.
Bluemoon

Quoting blink182 (Reply 4): Seeing as EK is neither a US company nor did this flight touch US territory, what jurisdiction does the NTSB even have over this?

May be GCAA doesn't has its own Code of Airworthiness.
That's why they involve the manufacturer's regulatory authority.

Quoting BluemoonUK (Reply 12): Quoting 3rdGen (Reply 8): but the engine keeps performing as expected But it didnt because they got a thrust asymmetry warning. Bluemoon

Yup, you're right, but they still thought it was OK to continue the 5 hour flight back to Dubai, so it certainly wasn't a warning that had serious implications on the engine or its running, according to those doing the diagnostic (and if they continued knowing that it was serious, well then I think its time someone called foul on Emirates). If we assume it was the former case then It was either a warning that came and went fairly quickly or they ran the engines at different settings or with the throttles at different positions with the engines synchronized all the way back to Dubai. Either way there's still a lot to be found out from this incident, I'll leave it at that, I highly suggest you visit the PPrune link I provided and read that post I've alluded to, it might answer questions as to the state of mind the pilots were in.

Quoting bonusonus (Thread starter): NTSB: EK 777 Continued Flight With Damaged Engine

Quoting 3rdGen (Reply 10): The NTSB is often asked to come in to help with investigations, they often go abroad to help with accident/incident investigations, however its only ever done at the request of the Country in charge of leading the investigation.

What is confusing me is that if NTSB is just helping the local authorities, why are they releasing a report? I just read the Wiki NTSB page and it does agree with what you are saying ie NTSB can participate if the aircraft is of US manufaccture or has US-made parts (engines, avionics, etc), or if requested because the local authorities do not have sufficient facilities. But none of this would make me expect we'd have NTSB issuing its own report.

Quoting Revelation (Reply 15): What is confusing me is that if NTSB is just helping the local authorities, why are they releasing a report?

Last few lines of the NTSB report:

"The investigation is under the jurisdiction of the General Civil Aviation Authority (GCAA) of the United Arab Emirates. Further information pertaining to this accident may be obtained from:

web: http://www.gcaa.gov.ae/en/pages/default.aspx

This report is for informational purposes only and contains only
information obtained for, or released by, the GCAA."

The NTSB is probably leading this investigation and has made up this report of their preliminary findings, the GCAA have authorized it for release directly without trying to pretend that they came up with the findings to make their own guys look like they did the job, I know some bureaucracies would have done that.

also says something about the engine itself...took a licking and kept on ticking...like it should

Still don't understand why the NTSB is involved in this.




It may be an American Aircraft but it is operated by a Dubai based carrier operating between two points outside of the US.



Does the NTSB's remit cover the world now ? !

Quoting Max Q (Reply 18): Still don't understand why the NTSB is involved in this. It may be an American Aircraft but it is operated by a Dubai based carrier operating between two points outside of the US. Does the NTSB's remit cover the world now ? !

NTSB was likely asked to participate in the investigation because of their experience, it was a US build aircraft/engine, or a number of other options. NTSB don't have jurysdiction, but they have experts and they wan't more knowledge.

/Lars

Quoting Max Q (Reply 18): Does the NTSB's remit cover the world now ? !

If they're going to get involved in every accident with US-made aircraft, engines or avionics...pretty much.

-Mir

Quoting Mir (Reply 20): If they're going to get involved in every accident with US-made aircraft, engines or avionics...pretty much

I don't think that will happen. The most likely explanation is, as Larshjort says, that they were asked to participate.

Quoting Max Q (Reply 21): I don't think that will happen. The most likely explanation is, as Larshjort says, that they were asked to participate.

They were asked because the safety body in the country of origin is supposed to be asked. AAIB probably says it best (this is from the preliminary report on BAW38)

Quote: In accordance with established international arrangements, the National Transportation Safety Board (NTSB) of the USA, representing the State of Design and Manufacture of the aircraft, appointed an Accredited Representative and was supported by a team which included additional investigators from the NTSB, the Federal Aviation Administration (FAA) and Boeing; Rolls-Royce, the engine manufacturer, also participated fully in the investigation.

Quoting cubsrule (Reply 22): They were asked because the safety body in the country of origin is supposed to be asked. AAIB probably says it best (this is from the preliminary report on BAW38) Quote:In accordance with established international arrangements, the National Transportation Safety Board (NTSB) of the USA, representing the State of Design and Manufacture of the aircraft, appointed an Accredited Representative and was supported by a team which included additional investigators from the NTSB, the Federal Aviation Administration (FAA) and Boeing; Rolls-Royce, the engine manufacturer, also participated fully in the investigation.

Part of the reason for the USA's NTSB to want to participate is to make sure if any liability goes back to Boeing, the USA based a/c's maker or if any component was made in the USA that may have contributed to the incident, it protects those USA companies from frivolous lawsuits being brought in the Plaintiff friendly USA court and civil legal system even if the incident occurred with no other connections to the USA.

One has to wonder about the factor of another post here noting fuel supplies are getting short in Moscow airports due to refining conflicts (to make heating fuel, the variations in the price of fuel), and if they dumped fuel, they would have had a hassle to get more after any inspection and repairs, enough to get 'home'. Still, why couldn't they get to an airport outside the Russian Federation where they could have made an emergency landing to have this checked out. I am quite sure the damage may have increased fuel use and possibly further damage occurred due to continuing the flight as scheduled.

Quoting ltbewr (Reply 23): it protects those USA companies from frivolous lawsuits being brought in the Plaintiff friendly USA court and civil legal system even if the incident occurred with no other connections to the USA.

Why shouldn't Boeing's design conduct be judged according to US law?

And if it is going to be judged according to US law, shouldn't US courts be the ones applying it?

Don't read too much into this NTSB report.

This report (link below) is listed as a 'Factual' which means it is "just the fact's Mam" - no conclusion or indication of error or fault. It is very dry "On this date, these (facts) happened". It gives no indication of fault, error or wrongdoing. So - any discussions that are happening about if they "should" or "should not have" continued are coming from other places, not the NTSB.

Save your ire about NTSB interference for a case where they do actually interfere. The NTSB may or may not issue a report of causation or errors, that will depend on what the investigating authority asks them to do.

If the report had conclusions - it would say "Probable Cause"

Here is a link to the NTSB report on the NTSB website

http://dms.ntsb.gov/aviation/Acciden...nszqhysmp3fn11/W09032011120000.pdf

Quoting CODC10 (Reply 7): The NTSB doesn't have "jurisdiction" over anything, really

Yes - the NTSB investigates and releases reports. They ask the FAA or other authorities to take action because they cannot. That is why in NTSB reports you will see things like "FAA Action acceptable" or "not acceptable." NTSB can be quite harsh in judgement of agencies who do have the authority and do not act.

Quoting Revelation (Reply 15): What is confusing me is that if NTSB is just helping the local authorities, why are they releasing a report?

Quoting Revelation (Reply 15): But none of this would make me expect we'd have NTSB issuing its own report.

Again - all the NTSB release was a "Factual" report. I have a hard time finding a problem with that. It is everybody else who is concluding things.

Quoting ltbewr (Reply 23): Part of the reason for the USA's NTSB to want to participate is to make sure if any liability goes back to Boeing, the USA based a/c's maker or if any component was made in the USA that may have contributed to the incident, it protects those USA companies from frivolous lawsuits being brought in the Plaintiff friendly USA court and civil legal system even if the incident occurred with no other connections to the USA.

The NTSB couldn't care less about lawsuits. The NTSB's job, which they take very seriously, is to promote transportation safety. The NTSB is not in the business of protecting anybody's financial interests. In fact, they make absolutely no bones about being frustrated with those that try to protect the airlines' or manufacturers' financial interests at the expense of safety.

Routinely, the NTSB will ask to be involved in an investigation if they believe there are potential safety concerns for either US-based fleets or operating procedures. So who asked whom could have gone either way in this case. If there had been a major accident involving this 777, for example, you can bet the NTSB would have asked to be involved within the first minute of hearing about it, because this is a plane flown produced in the US and flown by many US airlines and they would want to know if there are any safety concerns with the aircraft itself.

I don't understand why anyone is shocked or surprised with NTSB involvement, its very normal, they're the leading safety agency in the world and a lot of their bulletins and recommendations are almost always taken up world wide by most countries air transport safety agencies. Many nations friendly with the US often ask them to help with investigations due to their expertise. Can we consider this argument closed?

Quoting Transpac787 (Reply 2): The article said following one of the loud bangs on takeoff one of their EICAS messages was thrust asymmetry warning meaning the damaged engine was producing significantly less thrust than the good engine. Such an EICAS message following a loud bang *should* be cause to turn back, as the engine was obviously damaged.

Quoting BluemoonUK (Reply 12): But it didnt because they got a thrust asymmetry warning. Bluemoon

I suggest you check your "facts" before posting rubbish.

A "THRUST ASSYM COMP" status or caution (not a warning) means that the Thrust Asymmetry Compensation system (TAC) has switched off. It does NOT mean that the engines are producing asymmetric thrust.
The TAC is designed to provide automatic rudder input in the event of an engine failure on take-off. It takes it's inputs from various sources to compare thrust between the engines, but it will also switch off it receives erroneous or invalid info.

What the crew received was a series of STATUS messages. STATUS messages on the 777 are for crew info only and require no action. They are mainly an engineering function.

[Edited 2011-09-04 00:18:50]

Lets not condemn this crew when we don't know all the facts - only the crew on the day know these, and made their decisions accordingly.

If they got some indications that an engine (or some of its instrumentation) was not performing exactly as expected, they would no doubt monitor it closely. However, if the Manual or SOPs didn't require an immediate landing, why would they?

I expect they considered all kinds of things, for example:

What was the weather in Moscow, and would they have to hold to dump fuel first?
Altitude is your friend unless you are on fire (and they weren't on fire!)
Moscow to Dubai is an overland sector with numerous diversion opportunities should the situation deteriorate

It is easy to be wise after the event when engine damage was discovered, but the crew based their decisions on the information available to them at the time. If crews dumped fuel and declared an emergency every time an airliner's avionics gave erroneous readings the air transport system would grind to a halt.

Unlike some Anetters, the NTSB and any other Safety Authority are not motivated by apportioning blame. They will impartially examine what happened, establish whether safety was compromised, and if so, how can we avoid a similar event happening again.

Quoting Transpac787 (Reply 2): the damaged engine was producing significantly less thrust

Where does it say "significantly"?

The actual EICAS messages were:
THRUST ASYM COMP
ENG EEC C1 R
ENG EEC MODE R
ENG R EPR BLANKING
TURB OVHT SNSR ENG R

Quoting ThrottleHold (Reply 28):

  

Quoting Max Q (Reply 18): Still don't understand why the NTSB is involved in this.

The parties to an investigation and their respective rights and obligations are set out in Annex 13 on the Convention on International Civil Aviation.

Article 5.18
The State of Registry, the State of the Operator, the State of Design and the State of Manufacture shall each be
entitled to appoint an accredited representative to participate in the investigation.

Article 5.20
The State of Design and the State of Manufacture shall be entitled to appoint one or more advisers, proposed by
the organizations responsible for the type design and the final assembly of the aircraft, to assist their accredited representatives.

Article 5.22
When the State conducting an investigation of an accident to an aircraft of a maximum mass of over 2 250 kg
specifically requests participation by the State of Registry, the State of the Operator, the State of Design or the State of
Manufacture, the State(s) concerned shall each appoint an accredited representative.

The article didn't say how long after takeoff the bang occurred. If it was soon after rotation, One would expect debris to be found on the runway. I think that if the airport had found an emirates engine cowling on the runway or airport grounds they would have immediately notified EK dispatch, who should have made contact with the flight to recommend a diversion.

Quoting bonusonus (Thread starter): I'm not a pilot, but I can't imagine that continuing on after having this kind of issue at takeoff would be a good idea

The NTSB report says that a number *status* messages occured and were reported back to dispatch via AHM (Airplane Health Monitoring). That, in and of itself, means that no pilot action was required.

Quoting mgm414 (Reply 1): Well, Based on what I read somewhere previously, the messages they got required no actions for the pilots to return to the airport.

Exactly. A status message, by definition, does not require pilot action or even awareness...there is no requirement for flight crews to look at status messages. AHM reports everything (all levels of EICAS messages + maintenance messages) so that maintenance knows what to expect when the plane arrives but the flight crew can't even see the AHM data, let alone react to it. If there is an airplane condition that the flight crew needs to know about it must set an EICAS Advisory (or higher) level message.

Quoting Transpac787 (Reply 2): The article said following one of the loud bangs on takeoff one of their EICAS messages was thrust asymmetry warning meaning the damaged engine was producing significantly less thrust than the good engine.

That's not what the thrust asymmetry warning means.

Quoting Max Q (Reply 18): Still don't understand why the NTSB is involved in this.

They're the investigating body for the country that issued the original type certificate...they get invited when there is an incident. It's up to the NTSB whether or not the want to participate.

Quoting ThrottleHold (Reply 28): What the crew received was a series of STATUS messages. STATUS messages on the 777 are for crew info only and require no action. They are mainly an engineering function.

Exactly. Status messages are used to determine dispatchability...if something impacts dispatch it must set (at least) a status message. One dispatched, it has no impact...anything requiring flight crew awareness or input is a higher level (Advisory, Caution, or Warning) message.

Quoting kaiarahi (Reply 30): Where does it say "significantly"? The actual EICAS messages were: THRUST ASYM COMP ENG EEC C1 R ENG EEC MODE R ENG R EPR BLANKING TURB OVHT SNSR ENG R

Those are all status level messages...there is no requirement for the flight crew to even be aware of them, let alone do anything about them.

Tom.

Quoting tdscanuck (Reply 32): Those are all status level messages...there is no requirement for the flight crew to even be aware of them, let alone do anything about them. Tom.

Thanks Tom. An informative post from someone who would know.

This is all very much a grey area.

Lets say you are driving to work and your car backfires. You think it is very strange as it has not ever happened before. You briefly wonder if you should drive straight to the garage and be late for work, before dismissing the idea and deciding to go have it checked out another day...or week.

Admittedly flying is not quite the same but a 'bang' does not mean an engine is about to fail or that the aircraft is in imminent danger. As airline pilots we encounter problems all the time and most of them are minor and do not require the need to divert or declare an emergency. Some problems obviously require immediate attention and diversion. Where to draw the line between the two? There isn't one.

Assuming the EICAS messages were status messages as Tom says, the crew would not even be informed of a Status level message until 30mins after liftoff (Status prompt is inhibited for 30mins) unless they decided to look at that synoptic page themselves. They might have not encountered any EICAS warnings, cautions or advisories following the bang and takeoff (Although Thrust Assym Comp message is normally not a Status level message). The engine presumably was performing normally after the event (messages aside) and perhaps the crew considered the problem not severe enough to turn back, after all, the engine had not failed and why turn back with two operating engines? Not sure if the onboard camera was working or if it was a day or night departure but on the 773 that can give a visual clue as to how the engines look too.

In all likelihood, they would have spoken to someone in engineering back at their headquarters to discuss the issue with their engineers able to access real-time engine data to deduce that the engine was indeed running properly and not necessarily about to suffer a failure and basically that's what it is about. Is the engine going to fail en-route?

Now I wasn't there, so I can't comment on what was right or wrong or what I would have done. Engines these days don't go bang for no reason and when they do, it is indicative of a problem somewhere. A whole bunch of EICAS messages for different systems on the same engine after it goes bang is more of a clue that problems exist. Does the engine run properly afterwards? Is it going to fail imminently? Do you divert for an engine which is running properly? Its one of those things very hard to comment on because we were not there at the time.

Quoting CX Flyboy (Reply 34): They might have not encountered any EICAS warnings, cautions or advisories following the bang and takeoff (Although Thrust Assym Comp message is normally not a Status level message).

On a 777 THRUST ASYM COMP has both a Status and Advisory level message. It is not clear from the information I could find on the web if one or both displayed. The flightglobal article just mentions status messages so I was assuming it was the Status level version and not the Advisory, but I cannot confirm that. However, even if it was the Advisory message, the QRH procedure does not direct you to do anything other than cycle the TAC switch and, even if the message doesn't clear, it just notes that you would need to manually compensate for an engine-out and does not direct any further action.

Quoting CX Flyboy (Reply 34): In all likelihood, they would have spoken to someone in engineering back at their headquarters to discuss the issue with their engineers able to access real-time engine data to deduce that the engine was indeed running properly and not necessarily about to suffer a failure and basically that's what it is about. Is the engine going to fail en-route?

This is an important point...on a modern datalinked airplane, the ground typically has considerably better insight into the detailed state of the airplane than the flight crew. A consultation with either the Emirates, Boeing, or RR Operations Centers may have quickly revealed the common root cause for the observed messages and they may have determined it didn't impact further safe flight.

Tom.

Quoting tdscanuck (Reply 32): It's up to the NTSB whether or not the want to participate.

Not quite - the state of design/manufacture is entitled to appoint a representative whether or not the investigating state requests their participation(art 5.18), but if requested by the investigating state, they *shall* appoint a representative (art 5.22).