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Qantas A380 uncontained #2 engine failure

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Qantas A380 uncontained #2 engine failure

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Old 11th Dec 2010, 10:14
  #1801 (permalink)  
 
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Skywards747...

refer to post #1728...

Cheers
EW73
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Old 11th Dec 2010, 10:18
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Thanks, EW. I thought I have read all 1792 posts before I posted the question. Guess I missed that one.
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Old 11th Dec 2010, 11:46
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That just about sums up our society now

Bearfoil said <Some one came into possession of the keys to the Shed, the Shop, and the Boardroom.>

Dear Bear, you have encapsulated the mainstream world's current economic problem origins, not just this passing RR hiccup.

How else is it possible to posit upper management finagling themselves rewards of 300 x employees wages, and getting away with it? As they have for about the last 20 years.

Sure, when it does work, the intent focus can provide excellent results overall, but ye olde greed doesn't hide too far below the surface of most 'upper' management levels, and the destruction of bottom-up skills and initiative will give us greater probs within the next generational step than anything we've seen so far, I'll warrant.

Fortunately there are a very few business owners who are driving apprenticeship training hard, and boy, are they benefitting from it here! (in Oz)

And yet a local airline is taking about having new pilot recruits paying to fly with them, to 'help them build up their hours".

Guess which airline is going to go bust first.
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Old 11th Dec 2010, 11:59
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Overrode- Power?

Pacific Barron expounded:
To the best of my knowledge the TRENT 900 is capable of Thrust limits of 80,000 LB which could be bought by any Airline as required, at a price from RR. Each Airline only buys the certification needed & this certification is limited by a simple selection by RR with the computers. As QF only operate the engine at 72,000 LB the engine is already operating 10% below it's maximum design limits. The reason for the possible higher certification limits is to cater for the freighter & future stretch should this ever happen.
So I wonder why there should not be an over-ride setting that allows an engine which has non-certified power available to supply it if needed in an emergency? This might be a pay-for-use "Emergency Boost" that saves the plane in some emergency situations, especially during full-weight take-offs with a failing engine. As use-cases, imagine a 2-engine jet which blows an engine due to bird ingestion late in the takeoff roll or just after rotating.

Edmund

Last edited by edmundronald; 11th Dec 2010 at 14:36.
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Old 11th Dec 2010, 13:20
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With reference to the latest Herald Sun report (#1767). In the first few days it was "the engine exploded because it was serviced by Singapore engineers'. Then it was "Singapore pilots mutinied and refused to fly thier A380s". To day it is "The Fire Chief was to chicken to approach the aircraft". Enough of Bull**** from Down-under (pun intended).
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Old 11th Dec 2010, 14:42
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Beancounters

Bearfoil & JenCluse
Absolutely right. These charlatans are so myopic, they can see only to their next bonus. To ensure the long-term health of a company, I think that bonuses should be paid in stages; 10% per annum for four years, with the rest on year 5, provided that the profit level is maintained. Shareholders would agree with that, unless they are Stock Market speculators who buy and sell daily, and even they would see the benefit.

Some 15 years ago, when this dreadful business behaviour started to take its toll, one of my pilot colleagues commented:

"Beancounters - Bah! They're the wee bastards we used to give Chinese burns to behind the bicycle sheds."

It's time the "wee bastards" were taken back behind the bicycle sheds!
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Old 11th Dec 2010, 15:06
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Originally Posted by Bearfoil
Some one came into possession of the keys to the Shed, the Shop, and the Boardroom.
But not at Qantas, have a look at this link and count the number of solid Engineering qualifications on the board. These are guys who know and understand what they are doing.

About Qantas - Our Company - Qantas Board of Directors
 
Old 11th Dec 2010, 15:17
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edmundronald:
So I wonder why there should not be an over-ride setting that allows an engine which has non-certified power available to supply it if needed in an emergency? This might be a pay-for-use "Emergency Boost" that saves the plane in some emergency situations, especially during full-weight take-offs with a failing engine. As use-cases, imagine a 2-engine jet which blows an engine due to bird ingestion late in the takeoff roll or just after rotating.
It can be done, as in the case of APR on smaller aircraft. But there's a lot of engineering and flight test goes into that sort of boost. Asymmetric thrust implies things like Vmcg, Vmca, etc. that are not approached lightly. Read up on OEI rules for transport aircraft and you'll see the bases are well covered.

And please don't use the word "emergency" lightly. Engine failure on takeoff is classified as "abnormal", not "emergency". The airplane flies just fine OEI. A few years ago BA flew nonstop LAX - LHR with 1 of 4 out. A few years before that SR flew nonstop KHI - ATH with 1 of 3 out.
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Old 11th Dec 2010, 15:19
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On page 26 of this report;

http://www.atsb.gov.au/media/2888854...y%20report.pdf

(my emphasis in red)

Sequence of events drawn from the recorded data
0156:47
Airborne at Changi Airport
Engine thrust 72%

0200:22
No 2 engine oil temperature and pressure values begin to diverge from the recorded values for the other engines
Oil temperature increasing
Oil pressure decreasing
Altitude 5,330 ft
Engine thrust 87%



Do I interpret that correctly- thrust was increased AFTER takeoff?
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Old 11th Dec 2010, 15:19
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mike-wsm

Hell of a lot of "bankers"!!
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Old 11th Dec 2010, 15:24
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iskyfly

One possible interpretation:

Takeoff - 72% of 72K takeoff thrust

Climb - 87% of CLIMB thrust

Don't hold me to this, though.
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Old 11th Dec 2010, 16:57
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barit1 & Edmundronald

It is a very complicated situation with reserve thrust. Depending on the airplane-engine model combination, extra performance-reserve thrust may be available for emergency use during takeoff and go-around. For example, performance-reserve thrust is available for a 737-700 with CFM56-7B22 engines, since the -700 airplane can accept the higher CFM56-7B24 thrust. The engine control allows takeoff/go-around thrust up to this rating when the thrust lever is pushed full forward. If the installed engine has the highest rating offered for that 737 model (for instance, a 737-600 with the CF56-7B22 rating), there is no performance-reserve capability. Like the "overboost" thrust of the 737-100/-200/-300/-400/-500, performance-reserve thrust is for emergency use only.
-7B22 = 22,000lbs thrust
-7B24 = 24,000lbs thrust

I don't know how this works with 4 engine aircraft such as the A-380.

Turbine D
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Old 11th Dec 2010, 21:19
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I think the Spline Wear AD has to do with the IP Shaft, and not the LP Shaft.
Thanks, Bearfoil, for mentioning that. I may have drifted to the wrong coupling, accounting for my difficulty in determining how the coupling or the shaft splines were keeping the IPT from moving aft. I'm going to do a bunch of re-reading. Sometimes I fall into the keyboard at 2am.

Is this engine certified for 80,000 pounds thrust anywhere? No version of this engine seems to be certified in the US by the FAA, but that apparently is because there is no AC using it under US ownership. The ADs for it are picked up by the FAA and made effective in the US without change or comment (comment after the US AD is issued are accepted)-- but that is because there are no US interests involved. Paperwork reduction act, possibly. I would think that the US would have some interest in whether this engine could get its AC clear of LA on TO.

Perhaps the FAA did not certify the RR Trent 1000s-B787 as eligible for ETOPS because they were for test-bed AC, and had not accumulated enough flight time to establish ETOPS capability. Or perhaps the engine is still in development. I doubled checked after your comment, and that note appears to generally apply to all 6 of the certified versions. A TC is required to import a foreign engine into the US regardless of its developmental stage.

That has made me wonder if a similar situation might exist for using 80,000 pounds thrust with the RR-972(?)-A380 engines. Is there a European certification for that, or is European certification set up to cover this situation in the same way as FAA seems to be? It appears to me that the FAA considers each computer-authorized increase in the thrust output, of the same otherwise identical engine, to be a separate engine type, and to requlire a separate TC. This was true back at least to the days of the 747. I double-checked also that all 6 versions of the Trent 1000 are identical to the pound in weight. Are Europe and the US regulators divergent in this regard?

OE

Last edited by Old Engineer; 11th Dec 2010 at 21:24. Reason: Noted US import regulations require a TC.
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Old 11th Dec 2010, 21:47
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Do I interpret that correctly- thrust was increased AFTER takeoff?
Yep, that's quite normal. Whilst on the previous Boeings that I flew, a lower limit to the takeoff derate was the climb thrust selected, that limit is not used on the A380.
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Old 11th Dec 2010, 23:47
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Do I interpret that correctly- thrust was increased AFTER takeoff?
Yep, that's quite normal.
What is the purpose behind this?
I always thought that thrust was reduced after take off because the riskiest part of takeoff is over (obstacles cleared), and / or noise abatement.
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Old 11th Dec 2010, 23:50
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The departure off Rwy 20C in Singapore has a height requirement of 4000A at position SUDPO. This height is quite challenging for widebody jets and thus it is normal to do a derated takeoff and transition to full Climb thrust to meet that restriction. Prior to this major incident, I heard a QF A380 report prior to departure that they would probably be unable to make the SUDPO height so SIN ATC co-ordinated with Batam to have the restriction removed. This departure does cause the engines to be worked very hard and will no doubt be a factor mentioned in the ATSB report.
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Old 12th Dec 2010, 00:12
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Great info. Thanks GB, mrd, and barit
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Old 12th Dec 2010, 01:16
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Going Boeing:
The departure off Rwy 20C in Singapore has a height requirement of 4000A at position SUDPO. This height is quite challenging for widebody jets and thus it is normal to do a derated takeoff and transition to full Climb thrust to meet that restriction.
This certainly is not intuitive, but if you talk to engine people (esp. performance engineers) they love this routine. When taking off from a loooonng runway, near SL, a large thrust reduction is feasible - and the climb may become more critical. This means the engines can run a minute or two in a "warmup" mode before the higher climb setting. Great for long-term performance retention, lower fuel burn, more time-on-wing.

But it runs counter to pilots' experience and early training.
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Old 12th Dec 2010, 01:31
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Old Engineer

You ask a couple of interesting question regarding ETOPS and engine certification. First ETOPS: ETOPS is granted after an aircraft/engine combination has gone through the complete aircraft type certification process. For the B-787, this process is not yet been completed. Therefore neither the RR Trent 1000 or the GE GEnx have received an ETOPS rating at this point. As step two of the process, a rating is granted on an operator by operator basis which requires crews and other personnel to be trained in ETOPS operations. And as you probably know, there are different levels of ETOPS granted, 120 minutes 180 minutes, etc.

Engine Certification is given as a result of demonstrating the capability of meeting all of the extensive certification requirements. The actual certificate may list only one engine model or multiple engine models of the same engine. If multiple engines are listed, it would mean that the base model went through the complete process and subsequent models (higher thrust) went through a shortened certification process to assure selected critical criteria conform to requirements. This would be a concurrent engine testing/certification program. I would suspect this is what RR did as they advertise the Trent 900 is certified at various thrust levels to 80,000 lbs. of thrust.

The GP7200 engine was certified by the US FAA and EASA. I suspect that RR didn't ask for a US certification as there is no current US aircraft application at the moment.

Turbine D
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Old 12th Dec 2010, 05:34
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Thanks, Turbine D. That answers all my questions there.

So QF32 ran at 87% of 90%, or apparently 78%. Although the engine would be hotter starting the 87% due to following the derated TO, it would over some minutes trend back to a steady-state temperature corresponding to 87% continuous thrust. The time into flight at which the engine failed could be pertinent. The temperature, more or less, would initially ramp up, but then decay along a mathematical curve of the form 1/e.

Still, Qantas must have reviewed the procedure and determined what engine temperatures would reach at various TOW, and for how long. It's possibly another hole in the cheese, but doesn't seem by itself to be the cause. The 87% is of course 7/8ths thrust, and now Qantas is not operating over 3/4 max thrust.

At 3/4 max thrust, lose one engine [on TO, or in this case, other climb], go to 100% of 90% (or "max") thrust on each engine, and retain intended thrust. At 7/8ths max thrust, lose one engine, go to 100% of 100% thrust (beyond "max" thrust, but within the capability of the engine), and retain only 95% of intended thrust (from 20/21, left after processing the fractions). Use of the 5-min maximum TO thrust level instead would enable the intended thrust to be maintained. In the Trent 1000-B878 the TO max thrust level is 7% over max continuous thrust level.

That looks to me like Qantas is planning at the moment not to exceed 72,000 lbs thrust with this engine, in case of losing one engine while climbing above terrain or restriction as at Singapore, whereas before they might have approached 80,000 with one engine out. Is that the correct interpretation of 87% on the meter-- I'm not quite sure of the position along track relative to SUDPO when the failure event occurred. And now is QF is plotting longer a longer track to terrain at SUDPO for A380 AC of this TOW?

Correct me if I'm misinterpreting the situation. Obviously the plane was being flown within the Qantas rules at that time-- I'm not suggesting otherwise.

OE
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