A380 engine failure - Qantas
 

So engine failures are not uncommon in aviation today, but this one Nov. 4th on the Quantas flight involved engine parts that breached the wing structure and at least one engine could not be shut down.

Is it likely that this chain of events was not contemplated in the planning stages and that it will now require a re-design of the systems in the aircraft?

How many A380s with this engine are in service now?

Perhaps it would be a better start to what could become a long thread, to go back and change the spelling of Quantas to Qantas - an acronym of Queensland and Northern Territory Aerial Services Limited.

mm43

There was a video out there showing that only half the spoilers actually deployed on touchdown. Was it because the half happened to be powered by the hydraulic system that was lost or was engine 1 running beyond idle as Teh reason?

Just wondering!

Much of what happened was anticipated in the design. Sure some new facts will emerge and even some new lessons learned.

I hesitate to get ahead of the facts with predictions but I am well aware of the "what-ifs" and that even worse has and can happen.

It's the new lessons available for learning that I am most interested in So I will continue to follow the new facts part of threads

From an investors standpoint, is this likely to be a set back for the AIrbus parent company and RR?

Well American engines might not be so fuel efficient as the British engines, but they are necessarily more idiot proof because needs to consider the end user.

in times of FADEC it is not an issue anymore i think.

Not as fuel efficient as American engines? Give me a break. FedEx is now flying China-Memphis with full loads and soon to start Beijing-Memphis. Try that with the bloated whale. I do not know how long they are in the air but I bet it is close to 16 hours. FedEx dropped the whale, for what reason I do not know, but I bet they are glad they did.

I'm sure right now there's an army of engineers at Airbus pulling their hair out. I HOPE this was a unique case due to the environment or another particular issue.

If it turns out this is a design issue, Airbus is screwed.

Utter rubbish

I'm not an engineer but I would have thought the aircraft design should have anticipated engine failures like this and that the issue involving the inability to shut off other engines and or the loss of hydrolic pressure in this incident would be more problematic for Airbus than RR.


Thx.

Could we please stick to technical discussions here, like questions and how technical things things work.

All other opinion discussions fit quite nicely in Rumours & News items.

The design does consider such things under the regulations. Some of the design assumptions take into account the muliplicity of means to shut off the fuel as well as the means to have sufficient control of the aircraft to still land .

Seemed to work in this case

ADs affecting the 380 ?
 

AD 2010-16-07. RB211-Trent 970-84, 970B-84, 972-84, 972B-84, 977-84, 977B-84, and 980-84 turbofan engines. These engines are installed on, but not limited to, Airbus A380 series airplanes. Wear of shaft rigid coupling on several engines during strip. Earlier history; Refer to MCAI EASA Airworthiness Directive 2010-0008, dated January 15, 2010, for related information.
AD source and Link > Rolls-Royce plc (RR) RB211-Trent 900 Series Turbofan
===============
AD 2010-17-13. RB211-Trent 970-84, 970B-84, 972-84, 972B-84, 977-84, 977B-84, and 980-84 turbofan engines. These engines are installed on, but not limited to, Airbus A380 series airplanes.
To detect cracks in the low-pressure turbine (LPT) casings, which could result in the release of uncontained high- energy debris in the event of a stage 1 blade failure.
AD source and Link >
Rolls-Royce plc (RR) RB211-Trent 900 Series Turbofan
================

Two ADs for other models - but with similar causes. Vent tube blockages.

AD 2010-06-14. 700s series has a problem similar to 800s series. (Boeing 777s) Could this same problem extend to 900s series on A-380s ?
The Trent 800 has a similar type design standard to that of the Trent 700 and has also been found in service to be susceptible to carbon deposits in the oil vent tube. We are issuing this AD to prevent internal oil fires due to coking and carbon buildup in the HP/IP turbine bearing oil vent tube that could cause uncontained engine failure and damage to the airplane.
AD source and Link > Rolls-Royce plc RB211-Trent 800 Series Turbofan

AD 2010-07-09. RB211-Trent 700 Series. This AD supersedes AD 2007-02-05. These engines are installed on, but not limited to, Airbus A330-243, -341, -342 and -343 series airplanes.
Background; This AD results from further analysis that the cleaning of the vent tubes required by AD 2007-02-05 could lead to loosened carbon fragments, causing a blockage downstream in the vent flow restrictor. We are issuing this AD to prevent internal oil fires due to coking and carbon buildup that could cause uncontained engine failure and damage to the airplane.
AD source and Link >
Rolls-Royce plc RB211-Trent 700 Series Turbofan
=====================

Another AD for 900s series but no mention of uncontained explosion.

2009-18-13; Title: Rolls-Royce plc. (RR) RB211 Trent 900 Series Turbofan Engines
We are issuing this AD to prevent the release of a high-pressure (HP) turbine blade, which could result in an engine power loss or in- flight shut down of one or more engines, resulting in an inability to continue safe flight. Evidence from development testing and flight test Trent 900 engines has identified cracking on some HP Turbine Nozzle Guide Vane (NGV) Convex Surfaces.
AD source and Link >
Rolls-Royce plc. (RR) RB211 Trent 900 Series Turbofan
=================

Other ADs in a related model ( 800s series) with a mention of uncontained explosion.

2001-26-11; Title: Rolls-Royce, plc RB211 Trent 800 Series Turbofan Engines
LPC fan blade failure due to cracking, which could result in multiple fan blade release, uncontained engine failure, and possible damage to the airplane.
AD source and Link >
Rolls-Royce, plc RB211 Trent 800 Series Turbofan
===============
End

lomapaseo

Some questions come to mind. If the IP disc self ejects, are we looking at a disc failure as the cause? Or is it more along the lines of the "Rigid Coupling" feature, which I am assuming is the disc's bearing mount on the shaft? Generally, with turbine engines things get heavier and more robust as the Rotating mass approaches its center, the shaft, itself.

since heavier and more massive assemblies cause more damage when they fail, how specifically is this incident impinging on this model's maintenance and service life ?

Also, my intuition is that Intermediate Turbine is the focus of high acceleration and pressure increase of the air mass, could excess bearing wear be caused by engineering insufficient to contain this stress? Also, could you explain the oft misunderstood difference between the Turbojet and the TurboFan?

Thanks, bear

EASA Airworthiness Directives Publishing Tool ..... this might be the cause..

Bear

All avenues of investigation against all causes remain open at this time. Since I have'nt even seen what failed or any clear pictures of a closeup of the engine or recovered rotor parts I can't speculate and add any value to the understanding regarding a specfic incident under current investigation (nothing releasable)

I'll probably get back to you later on this when I have the time, to answer generalalities

one passenger reported a hole thru the winfg with wires and cables flapping around in it
isnt there supposed to be a scrapnel shield to stop stuff being thrown out and hitting the wings?

yotty

nice catch. Short of conclusive, but certainly tracking well (it would seem), to the end result. The terminology is not yank so I infer the "Coupling interface" to mean a thrust bearing.

Thrust, received by the face of the Shaft's shoulder, and negative thrust, if the engine is barfing, must be absorbed through a range of values, including vibration and high energy harmonics. The AD is a follow on to an original, perhaps not in time to preclude this event, even though the inspection alone creates problems relative to mitigation, and might be under "Pressure" to be declared "Deferrable".

Any repair would be a replacement of the disc and possibly the shaft. Time consuming, and expensive, to include a/c out of service. Leases don't take vacations.
I have seen a Shaft set of splines rub the disc face smooth, (generally the Shaft metal is treated to be more wear resistant than the disc hub). If a lubrication issue, flow restriction is necessary of the designed kind, but coking and carbon are not in the design consideration.

Is this about what you had in mind?

bear

Bear

As promised:

The mass of the released part is not nearly as important as its velocity and the shrapnel that accompanies it.

The idea was to fail-safe it to the point that it was extremely unlikely to fail.

Lots of considerations like; cyclic life, freedom from harmful vibrations, wear, fire and overspeed

Even then the aircraft is designed to minimize the impact to safe landing should the failure of this part occur. (good job there ):ok:

So what caused its release:confused:

keep track of the photos and press releases for any hints.

Lots is aleady available to the investigators from the recovered parts, although more part searching along the ground may be necessary.

No sense in speculating ahead of some more facts and "what ifs" are just that since the safety aspects are based on minimisation of combinations and not impractical flat out eliminination

Perhaps an engineer could state how much energy is contained in a Trent turbine wheel at take off power, and better still offer a comparison to something more easily understood.

I take it that the specific impulse would be measured in some reasonable unit like Newton metres, or foot pounds?

Or maybe, it's more like a KE thing?

Or is it a Joules thing? It's been a while since last I was in Mr Stirlings physics class.

For me as an operator...

these things happen....though not expected this early in their service life.

following the uncontained failure of the #2, with the accompanying debris shower of the area between #1 and #2, evidenced by the damage (internally and externally) shown in the leading edge area,
my concern here is that, had that debris shower damaged #1 in some way, either in a control system or causing an engine fire. My take of the events following the landing with regard to shutting down #1 engine, is that they had, in fact, no way of shutting off the fuel supply to that engine at any time post the #2 engine failure....and for me, that's scary stuff!

the 737NG has alternate paths for fuel shutoff controls to each engine...

EW73

BarbiesBoyfriend

"Parsec Tonnes"?

Bear
I hesitate to take issue with as great a pprune mind as yours. especially after an evening entertaining fellow pyromaniacs, but srely tonnes are a unit of weight, ie mass times gravity?

Yes to the above, just pick your favorite measurement sytem.

For the more common expression you might try

KE= 1/2 * Polar moment of inertia * rotational speed squared.

If I told you 1 million or 10 million foot-lbs would it make any difference?

It's sure to go through anything on the airplane that gets in its way

Parsec: Distance

Tonne: Weight.......... A play on Foot Pounds, a version you cite!!

Ah.......Fun with physics! No problemo.

I know that there is sweet fa that can contain a broken turbine wheel, thus the red line marked adjacent on old 'Century series' US warplanes.

Just wonder how many much wallop is contained within?

Like a car at 70? prolly too little.

Like a train at 70? nope, that would be more.

Like superman, trying to catch a four ton truck, loaded with Kryptonite? maybe....:ooh:

The problem with disc failure is that it represents blade failure "b" multiplied by how many blades remain attached at the perimeter of each part(ial) disc that is ejected.

b(n)(N)(Epartial)= take the train!!


bear

bear, ok, blades come off.

The disc tends to follow and this is where the real KE is stored and its energy is what I was wondering about.

Hey, it will wait til tomorrow.;)

Anyone want to speculate on repair costs?
 

Since there haven't been any pictures of damage to the lower wing skin, I'm wondering if this wing needs to be partially re-skinned, wouldn't it need to be done in a factory jig, and would Airbus be able to interrupt the production line to do it? And at what cost? What sort of a field repair is necessary to fly it back to Toulouse? Will this aircraft be back in service within a year?

1/2 I w^2 = energy
 

or one half times moment of inertia times angular velocity squared

Moment of Inertia, Thin Disc

RR will probably be liable for them plus lost revenue etc. What ever is in the quantas contract with Airbuss/RR or what is litigated after.

G27
 

you have seconds to change quantas to qantas before they turn up..........

My thought was the fail probability was more like 10 (-9). Oh well, at some point, it was 1/1.

barbiesboyfriend re: sequence/failure. My feeling is that this was not blade fail. The trail of lunch is more likely to be a start/failed disc, with its segments most likely retaining blades (if but for a millisecond). Then again if the disc migrated aft, the blades could have severed clean to start the cascade: debris/fail/debris/FAIL . Sioux City (UAL) was such a failure. The disc (why do I remember it was N1?) parted at an existing crack, and the conspiracists claimed the crack had been identified at a C check, but determined to be "within limits" (sic).

Since the entire midsection of this large powerplant is reported "missing", the shaft failed completely, and it is a wonder and a testimonial to RR that nothing more than a one hundred million dollar event needs to be expensed.

I don't think billet/forging/annealing or existing metallurgical defect is at play here. It seems more likely at this point, given the AD's that addressed the specific location of most likely failure, that it is a maintenance/inspection issue. The lubrication flow problem and required inspections, mitigations fall into an easy line of thought. Who wants to borescope this monster? Who else wants to STRIP it? It doesn't get any more remote than this junction to expose a potential million dollar repair. 400 cycles? that is a very pressurized demand on maintenance. For a New Engine? The implications are falling into place as we post. No one wants to be the bloke with the stick at the Hornet's nest. Given the AD(s), and I'm no expert, the (possible) dire consequences for the fleet are incalculable imo.

Let's capitalize the "Q" as well, it is a proper noun. :p

bear

You can calculate anything you want against failure probability, years of total jet fleet operations since 1956 to present or just time on the wing for this specific engine.

The design intent was zero and as such the future expectation must be brought back into compliance under Continued Airworthiness regulation.

The so called 10 (-9) numbers only apply to combinations of aircraft systems and specfically exclude any system like engines which have their own standards e.g. Part 33 regs

China-Memphis v's Beijing - Memphis
 

3pointlanding. What is the point of your post regarding China - Memphis v's Beijing - Memphis? Last time I checked Beijing was in China. As for SFC of American engines v's British engines I believe the RR's hold their SFC efficiency longer through the life of the engine.

Alternate paths for wing wiring harnesses or simply alternate power supplies (in fuselage)?

From what I've heard, a person could squeeze through the hole in the A380 wing, so it's likely that more than a single wiring loom was damaged (most aircraft front spar wiring runs parallel to each other).

The 737 classic runs one harness from the wing root along the front spar to the spar valve. The second harness runs along the rear spar out to the wing tip, through the wing and then back inboard along the forward spar to the spar valve.
The 800 rather than run the harness along the whole rear spar they took a short cut and ran it through the pylon fairing.

So back to the topic at hand. It seems the green hydraulic system failed, a logical conclusion given the catastrophic failure of the #2 engine and possible loss of fluid from that location. So, this would seem to indicate severe damage to that system from shrapnal or the complete destruction of one of the two engine driven hydralic pumps on #2. Correct? Also baffling to me is that there seems to be no isolation valves within the hydraulic system (other than the fire valve). Am I correct to assume that any leak in either of the primary systems leads to a loss of the system? Also interesting to me is that the nose gear steering is not triple redundant. If you lose the green system (which appears to be the case here), you only have the electro hydaulics to fall back on. Pardon the sophomoric questions but I find the though that goes into these designs fascinating.

-Old Ag

I don't have specific numbers, but one engineer friend once compared the fragments of a failed turbine disc (of a RB211 or CF6 for example), as having the mass and velocity of a cannon ball. Good Luck in trying to protect the plane from such damage.

And every engine manufacturer has had more than a few such failures over the decades. There are several possible causes, which the metallurgical people are adept at sorting out.

First - most obvious - is overspeed. In that case, the reason for the overspeed must be nailed down, and/or an overlay control system installed to provide redundancy. Think of a helicopter engine encountering a geartrain failure in the helo transmission. Without such loss-of-load protection, the gear failure induces a overspeed in the engine.

Second - overtemperature operation can degrade the material properties to the point that the disc (or shaft) cannot sustain normal operating loads. (This is what happened in the collapse of the WTC towers on 9/11).

Third - a material defect in the disc may not be detected for a few hundred or many thousands of start/stop cycles - until it finally lets go. This is called Low Cycle Fatigue or LCF. A huge amount of quality inspection and process control goes into disc manufacturing, and the state of the art improves year-by-year. Even so, the predicted safe life (in cycles) becomes part of the certification standards; once a highly-stressed prime-reliable part reaches its LCF limit, it must be scrapped and replaced.

Hope this helps.

Why is QF still grounded while LH & SQ are flying?
 

Without bashing any airline, can anyone knowledgeable comment on why SQ was at first reluctant to do any checks on their fleet of 11 A380, then at RR's recommendation, inspected the fleet but were flying 12 hours later with a "Fleet checked" impression given.
I understand a full boroscope is about 8 hours to complete.
QF has found a further 2 engines worthy of removal and stripdown.

Does this indicate that SQ/LH believe the 970/972 differences are sufficient to "protect" them, or that SQ in particular (LH's hours are so low at this stage that theirs was probably a fair call) believe it is a QF maintenance issue rather than a design or manufacturing issue?

Anyone care to comment whether the #2/#3 engines showing up as worthy of inspection indicates that reverse thrust may be a factor?

(Not a reporter. Worked 14 years in the industry in Avionics and overhaul)
Cheers