Article: NTSB: Emirates 777 continued flight after loud bang, messages
 

source

By John Croft

The US National Transportation Safety Board revealed in a preliminary report issued 30 August that an Emirates Boeing 777-200ER crew continued a 5h flight from Moscow's Domodedovo airport to Dubai on 5 March after hearing a "loud bang" and receiving several error messages on departure.

Pilots of Flight 132 (A6-EMH) reported the incident after landing at Dubai, according to the General Civil Aviation Authority (GCAA) of the United Arab Emirates, the authority handling the investigation.

"Following the bang a number of status messages were annunciated, these messages occurred over a 16 minute time as per the Boeing AHM (airplane health management) data," the report stated.

Messages indicated a problem with the right Rolls-Royce Trent 800 engine, and included a thrust asymmetry compensation message that is issued when the flight control computer automatically uses rudder input counter the yaw effects of a failed engine.

Four additional messages were received on departure, followed by two AHM messages after landing.

Flightglobal's ACAS database shows that the 14-year-old aircraft is owned by Veling and has Trent 884-17 engines, members of the Trent 800 family. As of 31 June, the aircraft had accumulated 61,581 cycles and 12,945h, according to ACAS.

Inspection of the aircraft in Dubai revealed "a large section" of the right engine's inboard fan duct and thrust reverser were missing, starting at the trailing edge and ripping forward.

Overall, officials estimated that 2.8-3.7m2 (30-40m2) section of engine covering to be missing, along with the primary exhaust nozzle outer skin. The primary nozzle inner skin had been "holed in several locations at the 12 to 1 o'clock position," the report stated.

External to the engine, the one tyre on the main landing gear "was observed to have a large cut to the sideway" of approximately 36cm (14in), officials said. Examination of the aircraft and engine was to continue but the results have not yet been posted.

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.

I note it says "status" messages. It could very well be that none of these had an associated abnormal procedure, so the implication in the article that the crew ignored something they shouldn't have is a bit naughty.

Sounds like something happened, the aircraft systems noted it, but it never was determined (by those systems) to be serious enough to post a message requiring crew action. And since the flight completed uneventfully, its hard to argue with that determination.

Messages indicated a problem with the right Rolls-Royce Trent 800 engine, and included a thrust asymmetry compensation message that is issued when the flight control computer automatically uses rudder input counter the yaw effects of a failed engine.

What does the QRH procedure say?

Unusual utilisation?
 

Average of 13-minute flight time. Or maybe it's block time, in which case DXB is amazingly efficient.

A lot of training flights?:rolleyes: Sim broken?

If Boeing uses the term "status message" in a manner consistent with us (or is that vice versa) I'd guess "nothing at all" - status messages don't require crew action.

61K cycles as quoted is highly suspect. Aside from it being well beyond the base DSO of 40K, that figure is well out of the ball park for a 14 year old long-haul aircraft.

I think its the FH number that is bogus too.

14 years is 122 640 calendar hours. 12 945 FH implies the plane is being used only 10% of the time. Unless its a hangar queen, that seems impossible.

Bets on it being 61k hours and 13k cycles? That'd be 50% utilization and 2.5 cycles/day which sounds more credible.

It would be 61k hours, and 13k cycles, sounds about right for an aircraft that also does short hops around the ME and into Europe.

That works out to be an average utilisation of around 12 hrs a day, which also sounds about right.

Since when journalists knows how to assess a 777 Non-Normal situation better than a trained crew!
Status Messages = no actions required and no troubleshooting either. Only maintenance on ground can take care of a Status messages.
Cycles are important, but maintenance in ME is probably one of the best in the world!
This episode won't affect the almost clean T7 record!

What date? That'll be the 1st of July then:ugh:

According to Aviation Herald, here are some of the status messages received:

You be the judge....

...Gladly.

There is no checklist or remedial action required for status messages. They are for information and maintenance action.

What are you suggesting should have been done? Shutdown an engine in defiance of the Boeing Bulletin specifically recommending against it? Divert when there was no actual non-normal situation?

I'm judging they did exactly as they were supposed to....

Well, I AM a 777 pilot and....

Consider? Certainly. I believe MCC was contacted by SAT PHONE, the situation assesed, and the decision that it was safe to continue made, resulting in a safe landing at destination.

No, the situation was not typical and thus required management, which was done. Are you suggesting anytime ANYTHING unusual happens, a return to origin is required?

Where exactley is anyone (and grizzled, you are doing so by implication) getting the idea that anything other than a professtional job was done?

ETA, for some reason this post keeps appearing before Check Aiormans post, even though it was written in response to it!!

I am not typed on the 777, thus cannot (and will not) judge the crew. However, for the experienced 777 crews, even though no action is required for status messages, wouldn't the appearance of multiple messages connected to the engine cause you to consider returning to the airport?

My rationale would be that it wouldn't be the first time a computer system generated seemingly innocuous messages when a more serious problem existed.

Is it typical of the plane to generated multiple status messages during flight?

Thanks for that reply.

I'm not saying that any fault requires a return, but I would certainly let the PIC know that I'd have reservations about continuing the flight. If he elected to continue, I'd be paying extra attention to possible en-route alternates just in case.

And to be clear- not saying the crew did not act professionally. I'm just trying to get a deeper understanding of how these situations are dealt with.

Wizofoz,
You sound like a decent EK trainer, who is appropriately rated on the T7, unlike some of the armchair pilots we see here on this forum.
Pray tell me then, what EICAS messages do you get on this airplane between 80kts and 400 ft AGL...??!!
I think the answer to my question should answer your query WRT the lack of eicas msgs and the presence of status msgs only.
Why then was the airplane dragged thru 5 hours of a trip.
Who was trying so desperately trying to get the plane 'back to base'. Which one of the 2 morons on the FD was trying to brown nose him/herself into the managments pants to enable a promotion...
And at what cost.
Last but not least, what was 'managment's' advice on ACARS when the AHM msgs hit home...
All wonderful questions, with dubious answers, I am sure..

Some posts missing.....this one written before post #13.
Still doesn't answer my question.

After take off a bang is heard and several status messages (all related to the engine) pop up...
The identification phase surely tells you that the bang is related to the engine as the status messages confirm, so why continue the flight knowing there is something wrong with the engine?!
Maintenance will always want the aircraft back home... its the crew in the end who decide..

Wizofoz...

Re: Huh??? All I did was provide some clarity to the discussion by showing what some of the actual status messages were (at least according to Av Herald). Your response suggests you are a tad sensitive re this particular event. FWIW, I certainly am not hung up on it one way or the other.

When I have something to say (on pprune or elsewhere) I say it. I don't imply. Sheeeesh....

loud bang
 

As a RATED Pilot on the 777, any "loud bang" followed by any status msg(s) would have resulted in a return to the departure airfield. Irregular status messages could have been managed and continued to destination, however these coupled with a "loud bang" is just waiting for the swiss cheese model to unfold!

Clearly the the report would have discussed these items if there was any doubt about the crew acting correctly in response to the information available to them.

They did their job and the outcome was a success. There are, however, questions to be answered about the cause of the tyre failure and the resulting damage.

Some of these responses miss the obvious , the report said a large chunk of reverser fell off , even on our modern hi tech a/c there is no EICAS message for that . The messages that came were probably due to damage to wiring caused by the failure . been quite a few of these failures now , shows the difficulty with composites !

But they bear a certain relevance, that why they are displayed. "Unusual" status messages could be an indication of more serious messages to come. It is up to the pilot to put two and two together. Just because there is a status message NOT requiring any crew action (for now) is it safe to continue.

What about the 777 pilots and non-777 pilots that disagree? Where's basic airmanship and common sense with regards to safety? Plus, after having seen any type of message about thrust asymmetry (and audible clues) I would have returned. End of story.

Engine surge/stall gives a loud audible bang, or series of bangs, temporary loss of thrust an not necessarily any damage. A bang and a status message doesn't necessarily indicate a continuing problem with or damage to the engine.

ANTI AB LOBBY: "You guys are relying waay too much on computers and are losing airmanship"

AB LOBBY: "Go away dinosaur"

*BANG*

AB LOBBY: "Computer says all hunky dory - keep going"

Who's the AB lobby and whats their relevance to 777's ?

Firstly, I'm not a commercial pilot.

@Contacted
"A new bulletin relating to Thrust Reverser Inner Wall failure now recommends landing at the nearest suitable airfield.

If this particular flight had this problem (since the bulletin issue) then the crew would not have continued to Dubai."

If that is the case then in this particular case, and with hindsight, you'd have to say that return to airfield would have been a good decision (although maybe for the wrong reasons at the time).

I'm curious though, if they had decided to return would they have had to fly around burning fuel for maybe 5 hours? Given that the thrust reverser was apparently affected this could be quite significant no? As the flight was presumably not over any huge body of water, maybe calculating your possible diversions and carrying on with vigilance makes quite a lot of sense?

MCC monitor real time engine parameters ... continue didn't jeopardize safety ... i'm pretty sure that flight was closely monitor all the way to touch down and beyond!

Any chance that we can disscet the NTSB full report rather than a newspaper's summary of what plays to the public.

I don't have a hangup about status messages alone, but I would be curious about the kind of stuff captured on the DFDR.

You're all assuming the report of a "loud bang" is accurate. Perhaps there was or perhaps there was not. This exact same failure just occured again last week on a HAM-DXB flight. That crew did not report a "loud bang".

The other thing that seems to be forgotten in this discussion is when the Status message inhibit ends. To refresh some memories or let those who do not fly the B777 understand it is, "cruise or 30 minutes after lift-off, whichever occurs first".

You're all assuming their was a lound bang and then a bunch of messages. Not to be blamed as that is the way the report makes it sound. But was that in fact the case? I highly doubt it.

There is no NTSB "Full report", and likely never will be. There's a summary of info on the NTSB website, but NTSB isn't the lead agency.

The NTSB version of the info is here, copied below for convenience:

If the flight had been in the opposite direction, from Dubai to Moscow, would they still have continued?
Would you?

In response to King On A Wing.

The inhibit system means most master cautions are inhibited between 80kts and 400ft. But AFTER 400ft, any conditions that remain detected are then annunciated. I'm no sure what you are getting at. Are you saying that because a non-normal occurred before 400ft, it would not have been annunciated?

Not so-the annunciation would just have been delayed until the end of the inhibit period for that condition. If you are a 777 pilot and not aware of that, may I suggest some remedial study....

Grizzled-my appologies. My colleagues are being unfairly slammed here by some pretty ignorant comments, I accept yours was not one of them.

Bigmouth,
Having assessed that the aircraft was safe to continue it would have been a commercial decision from the company.

I've had a similar occurrence. A Black Cockatoo once went through my By-pass duct and took a chunk of the lining with it. Ok. That's happened. The engine is stable, no change in parameters, no thought of a shutdown,what exactly is the jeopardy in continuing?

It is not an engine failure; the flight is not ETOPS.
They did not disregard any "land asap" advisory.

This is one of those cases for a Command course and I think those in favour of diverting or continuing will be divided in 50/50.

The crew took the commercial view and with the info we have so far (and from my armchair) I totally agree.

Mad )Flt) Scientist

Thanks for the factual summary.:ok:

Count me in as one of those that says it's too early to express opinions about the conduct of this flight.

Too bad the NTSB has place themselves on the front page without being able to comment fully to sites like PPrune

RTB required only after second bang, per Qantas.

Mmmmm.... Moscow nightstop..... No Thanks :ugh:

JooJoo , I think you nailed it , with regards what the manufacturer would have prefered. The bulletin issued as a result of this incident. However the crew were doing what thay were trained to do at the time . Makes one think does'nt it ?

plenty of moscow night stops as it is in dxb :}

Wizofoz...

No worries Mate. I too get frustrated at times at pposters who suggest a certain action by a certain crew was not appropriate -- with no evidence to support such a statement. I simply ignore such comments if they are clearly made out of ignorance, but when they appear on a professional thread, or from someone who purports to be a professional, I do wonder...