RE:Qantas A380

[brad kaste]

The Qantas crew whose A380 suffered an uncontained engine failure earlier this month had their hands full in getting the super jumbo back to Singapore. Shrapnel from the engine disabled one of two main hydraulic systems, hampered the fuel transfer system, punched a hole in the forward wing spar and caused a major fuel leak. The cascading nature of such failures meant the pilots couldn't dump enough fuel to bring the aircraft down to its maximum landing weight and the fuel left in the airplane was unbalanced. Flaps, slats and spoilers couldn't be fully deployed and the gear had to be dropped manually. Once it was on the ground, the anti-lock brakes didn't work and, since the damaged engine was an inboard one, there was only one left for reverse thrust (the outboard engines of A380s don't have reversers because they often overhang the grass and might be FOD damaged). The heavy, significantly disabled aircraft needed virtually all of the 13,123 feet of available runway. The whole wing might have to be replaced and the aircraft is expected to be out of commission for months. Meanwhile, the cause of the engine problem has been determined and it's just adding to the PR problems facing manufacturer Rolls-Royce.

According to the Courier Mail, newer versions of the Trent 900 engine installed in aircraft built after the Qantas jet in question had redesigned bearing boxes to prevent the oil leaks that resulted in the engine explosion. Airbus sales chief John Leahy told the paper he wasn't sure if the three airlines that chose the Trent for their A380s, Qantas, Singapore and Lufthansa, knew about the changes and which engines had been upgraded. Other A380 buyers chose the Engine Alliance GP7000

1. Bus #2 is supposedly automatically powered by Bus #1 in the event of Engine #2 failure - didn't happen.

2. Buses #3 & #4 will supposedly power Bus #2 in the even that the auto transfer from Bus #1 fails - didn't happen.

Numerous electrical functions were inop – with the high weight and unable to dump fuel symmetrically coupled with inop flaps/slats performance data showed only 100 Meters of margin on the runway after landing – exactly what was left on the 13,000’ + runway.

The attached pics show some of the damage – note severed electrical wires, severed fuel main, and nearly severed forward spar.

[Wing_Z]

And could have been a major disaster.
This is probably a testament to modern airliner design - multiple load paths, and systems redundancy allow "measured" degradation rather than outright single-step failure.
If I were Airbus, I'd tout it as a triumph, (and collect the cash from RR)

Wonder what a new A380 wing might cost? $300 million buys you an aircraft, so it won't be all that cheap.

[kilo delta]

The A380 wings are an engineering marvel ...

Here's an interesting video clip featuring the wing build process

LpSgj-tKelY

[fliger747]

Always interesting to see how different design philosopies work. I take some interest as Captain on a competing product. Subsequent damage from an uncontained engine failure has been an issue in several crashes over the years on various aircraft. The most spectacular was the UAL DC-10 that lost all hydraulics.

I find a flat note on the oil leak scenario. The incident occured shortly after takeoff, the leak rate would have to be rather astounding. Having had an engine (747-400/GE) loose all it's oil in flight before (HKG-DXB) we not only didn't have it explode, there was no damage and after repair of the offending oil line it sucessfully returned to service.

The spar is an interesting issue and potentially worrysome as the test wing failed short of it's ultimate design load and was not to my knowledge re-tested.

Though all of these cockpits are certified to be operated by just two pilots, and others are there as reliefs, it is my experience that having the extra crew on hand at such a time is a big plus.

Our engines on the 747 hang out over the grass as well......... Not usually too much of an issue except for some rather unkempt fields such as Kabul.... Or snow berms....

Redundancy of systems is a great thing! Sure they had their hands full and much will be learned.

Cheers: T

[Wing_Z]

...take some interest as Captain on a competing product.

I had a mate who captained 747's and also delighted me with his totally one-eyed view on matters like this! ;)


...The incident occured shortly after takeoff, the leak rate would have to be rather astounding. Having had an engine (747-400/GE) loose all it's oil in flight before (HKG-DXB) we not only didn't have it explode, there was no damage and after repair of the offending oil line it sucessfully returned to service.

It was astounding...the engine blew up! And comparing a Trent 900 to a GE CF6 is a little disingenuous, they are very different animals. Not least, the 900 is about 50 years younger than the GE and hasn't had the development time. RR certainly has to explain why they changed the design, but neglected to inform earlier customers.


The spar is an interesting issue and potentially worrysome as the test wing failed short of it's ultimate design load and was not to my knowledge re-tested.
Oh come now, the aircraft is FAA and CAA certificated...do you imagine this happens despite certain rather important requirements not being met? I'd agree the spar is interesting, but only because the wing did not fall off.

As to thrust reverse, airliners are certified to land without TR. It's weather- and location-specific whether TR actually pays for its weight and complexity. The A380 doesn't need 4 TR installations, simple.
As to losing an engine, generally the opposing engine's TR is locked out as a matter of course (even on 747's)

Just in case I sound too evangelical...I also think the big 'Bus is fugly.

[PeteHam]

QANTAS have certaily had a bad run lately .........

Qantas mishaps since 2006<?xml:namespace prefix = o ns = "urn:schemas-microsoft-com:office:office" /><o:p></o:p>
http://www.news.com.au/travel/news/qantas-mishaps-since-2006/story-e6frfq80-1225949509032

Pete.

[wiltzei]

"Drama in the cockpit: Qantas crew faced 54 alarms" (http://news.yahoo.com/s/ap/20101118/ap_on_bi_ge/superjumbo_woes_22)

[fliger747]

Actually not comparing the Trent to a GE at all, they are different to Pratts etc. I fly mostly CF6 Planes, but we have/had a coule of Pratt planes in the inventory. Very different birds with good and bad points. Engines shouldn't explode. Over 20 Dreamliners sitting all painted up at Paine Field without engines due to a catestrophic engine explosion in a test cell. Hope Rolls gets all their issues worked out.

A Boeing test pilot aquaintance (we flew together) once told me he had seen an ungodly number of occurances that the engineers had said there was less than 1 to 10 minus 6 or higher of ever occuring in a large number of flight hours. So "stuff happens". No four engine airplane I ever flew "locked out" reversers, but perhaps Airbus does this, haven't flow one. Indeed the aircraft are certified and landing distance for dispatch computed without reversers, however many such calculations and certifications are based on things like.... antiskid working. If it had been a tropical downpour in Singapore (a common occurance) things might have been even more exciting.

Qantas has very experienced crews from top to bottom. Some other carriers rely on much less qualified relief and first officers. Glad they pulled it off, elimenating the distractions and knowing what cures are counter productive is critical to managing a very confusing situation in an appropriate time based manner.

Admittedly much training, which is job based (job on the line evaluation) usually has only one emergency at a time, which if the training was emphasized rather than the evaluation, one might be able to explore the world of multiple simultaneous failures and learn something.

Ya never know how much redundancy you will need!

Cheers: T

[Wing_Z]

I could be talking through my hat about thrust reverse, I thought I'd read somewhere that the Electronic Engine Controls cross-read their condition on the opposite engine.

I said in the other thread that their time had not come, but really, quoting Wiltzei's link:
"As luck would have it, there were five experienced pilots — including three captains — aboard the plane...In all, the crew had over 100 years of flying experience."
and I think that may have had a great deal to do with the successful outcome in dealing with 54 in-flight alarms.

[Roadburner440]

I have followed this incident with very high interest since it has happened. While an uncontained engine failure is severe enough on it's own I was no alarmed by the initial news reports. When I saw the plane sitting on the tarmac with the landing gear doors dangling down, and them drowing out the #1 engine with 3 fire trucks did the seriousness of what they had faced set in. While engines do cross talk it is pretty much limited to torque matching when you are within a certain % number. When you leave that range the torque matching is not enabled. Even then you need to have the engines harnesses speaking to the other engines through the various buses which to my understanding would not have been possible due to the damage done to those wire looms on the forward wing spar. Luckily modern jet engines with FADEC are self sustaining, and it kept on running for the remainder of their flight (and a hour or so after). I really attribute their survival of this to a lot of luck, and a very good design by Airbus. While most people I have seen on other forums (pprune.org/airliners.net) have gotten into the Airbus bashing. This could very quickly go either way on any platform of aircraft. It is also a testament of the true professionalism of these pilots that were on board at the time (some 5 Captains going off the articles I have read, but I am unsure if that is true/possible) that this didn't turn out far worse.

As far as the thrust reversers go someone was saying the outboard engines are locked out because they hang over the edge of the runways at some airports, and they do not want them blowing FOD forward to be ingested by the engines on landing. I would think an engine the size of a Trent 900 would be able to pull anything out of the grass anyway, but maybe with the aircraft moving forward so fast the objects do not have time to make it to the intake.