11/04/2010

The Qantas A380 engine failure - a disaster for Rolls Royce?

A first serious incident happened with an A380 – the first Qantas A380, registered VH-OQA, made an emergency landing in Singapore, not long after taking off from the same airport.
Pictures show that the aft part of the No.2 Trent 900 nacelle is missing. Eye witnesses from the ground said that there was a loud bang (or explosion) and trails of smoke after that.

All this points to an uncontained failure. In recent months we saw two other uncontained failures in RR engines – first a RB211, also with Qantas, but on a B747-400 and then the Trent1000 on a testbed in Derby.

If at least the Trent1000 failure and the -so far- suspected failure in the Trent 900 of the A380 are in any conjunction remains to be seen. At least it is not good publicity for Rolls Royce in a time that is not easy for the No.2 engine maker:

  • Deliveries of the Trent 900 are, due to the production problems and slow ramp-up of the A380, not in numbers that were anticipated in the business case. Any profit from this engine program is delayed by years (the same is also true for the GP7000, of course).
  • Even heavier probably , the Trent 1000 drags on profit margins. The 787 is late by almost three years – if the first delivery in mid-February will be met. According to the original ramp-up plan, there should have been around 200 B787 in service by now, maybe half of if powered by the Trent 1000. The performance inprovement programs, aimed to meat the promised fuel burn at the aircraft probably doubled development costs.
  • Development of the Trent XWB is in full swing, costing a lot of money, too.
So one could suspect that RR is running into a cash problem. Luckily there are the Trent 700, the leading engine for the A330, and the V2500 and Airbus upping deliveries for the A320. But if these two "cash cow" programmes can save RR in the long run, if there would be a main technical problem in the Trent 900/1000 (and maybe XWB), is questionable. A fundamental technical problem, a desígn fault, could end up in the grounding of the whole Trent powered A380 fleet. Qantas grounded their fleet of six A380 immediately after the incident, Singapore would be hit heavy with eleven A380 in their fleet today, Lufthansa so far took delivery of four aircraft.

It is too early to call today’s failure a disaster for Rolls Royce (and subsequently, for Qantas, Singapore Airlines, Lufthansa and, if the worst comes to the worst, Boeing and all their B787 Trent 100 customers) – but the possibility is there…

Update: meanwhile is is obvious that an uncontaines failure happened. Pictures are showing damage to the wing - Singapore Airlines effectively grounded their fleet also. Officially, all flights are just "delayed" until the engines are inspected, but a 100% inspection of the disks for such a failure would mean to take the engine apart...

Update 2:
Just found the preliminary report of the uncontained failure in the RB211-524, which happened on August 30th. It can be found here.
The key observations are (quoted from the report):

All of the turbine blades had separated from the IP turbine disk.
Blades from the three LP turbine stages were either fractured through the airfoil section or separated from the disk.
The LP stage 1 nozzle guide vanes were destroyed. The remaining LP nozzle stages were substantially damaged.
The LP turbine bearing and adjacent phonic wheel and speed probes were destroyed.
• The IP shaft was severed towards the aft end.

This picture is obviously a part of a turbine disk that fell on the island of Batam - we will soon hear if it is also the IPT disk - at least all baldes are missing.

The Trent 1000 failure also happened in the IP Turbine. If now yesterday's failure also can be tracde back to the IPT, I would be happy not to be employed in Derby...

13 comments:

  1. Is there any relavancy to this issue with the A & B models of the Trent 1000. That is, the problem in Darby was on an A model. The 787 is now changing to the B model.

    In any event, however, does this raise larger questions about the RR engines and Carriers may wish to go with the GenX ones as a result.

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  2. Good question that is!
    I guess we will find out when we hear what kind of inspections were ordered by RR and Airbus.

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  3. Is there a substantial difference in the design of the RR 1000 A & B so as to remove the 787 engines from implication?

    However, from what I am reading, it seems to follow the same problem issue with the shaft and the possibility of an oil accumulation and overheating.

    How long do these investigations take? As long as there is suspicion it must make Carriers that ordered it uncomfortable.

    I wonder if this will contribute to any delay issues with the 787 ...or excuses to delay.

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  4. Excuses to delay...I guess there are a few (educated) people who would say the same - I have no insight.
    Also I do not know what are the hardware differences between the T1000 Package A and B engines.
    But is well known that the oil system of the three-shaft-design is a little hard to handle.
    I don't know the directives that RR and Airbus gave out, but I guess a full boroscoping of the engine or at least the now failing parts - can take from an hour to several hours.
    Problem is: if there is a general design flaw, the problem occurs inflight...

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  5. The Darby investigation took several weeks and I am not sure it is fully determinative.

    But RR had issued a service warning for the Airbus 900 engine so they were aware of some issues that had to be carefully watched.

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  6. Could you clarify your last remark about why you would not be happy to be employed in Darby and the IPT disk.

    Was there some oversight or failure that should have been discovered or indicated.

    What is the relationship between the Darby incident on a Trent 1000 and the Quantas incident 0n a Trent 900. Is there a commonality of structure, etc.

    Is this a remediable problem or a major one?

    I am still very concerned about its impact on the 787....any clarity here?

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  7. The basic architecture of all Trent machines is the same - in fact, the Trent's are part of the RB211 family. The fact that we now had three uncontained failures at least in the same area of the engine (we don't know yet if the the broken disk that was found is the HPT of the IPT) and the EASA AD pointing to the IPT as sort of a problem area is at least an indication for a systematic design flaw. Qantas also points to either a material problem or a design problem.

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  8. Do you know or can guess whether and when this becomes detemined...that is, it is recognized as a design flaw....is it a statistical matter...a legal matter.

    Can it be corrected and what does it take to correct it...does it have to be tested...certified....etc.

    What satisfaction can RR give to customers....does it happen after wear?

    Since you are an engineer, you could address at least the technical engineering engine issues that have to be overcome.

    If I were ANA I would be quite concerned.

    I suspect delivery delays ......and alot of blaming....

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  9. Sorry, but without knowing the facts you can do just wild guessing - and that range from "just inspect the engine a little more often" to "complete redesign". The truth is usually somewhere between. And there is a lot of space in between...

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  10. How is it that Singapore Airlines resumed flights after inspections and Quantas is indicating a similar orientation.

    I am suggesting that you try to address soem of the prior questions with as thoughtful a guess as one can give without the facts...or at least the facts that we know at this time.

    I am wondering how long a thorough investigation will take ....one of the comments on Flightblogger ( right next to yours) sounded quite intelligent about the nature of a particular material .....

    In your mind, how does this play out?

    How and when can any anxiety about these engines be satisfied??

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  11. Could we assume that it is the HTP of the IPT that was the cause of the failure.

    Now what. Does that save alot of investigation...does it require a new HTP or IPT...repaired, restored, refortified, replaced?

    Does this take alot of time and engineering.....

    Would inspections, software and replacement work..and does that have to be redesigned.

    In your example you say it usually lies somewhere between inspection and redesign....if so, how complicated, difficult, time consuming is that?

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  12. I am really sorry, but it deos not make any sense to speculate how long anything that maybe has to be changed in the design would take a this time. Let's wait a few days...

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  13. The Rolls-Royce Trent 900 engine is a very nice complex machinery with triple shaft arrangement. Lubrication on a single shaft jet engine is already complex enough with the need for oil scavenging before it goes out and combusts, causing overheating and pollution.
    Rolls Royce engine failure

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