firstfloor
I wonder about some things relative to the airports and the A380. At LAX, there are two parallel runways, one (25L) is 11,095 ft. X 200 ft, the other 12,091 ft. X 150 ft.
TO on the wider runway is at 250.2° and would generally be into the wind (breeze off the ocean) but at time could be downwind (Santa Ana winds from the mountains to the east of the airport.)

At JFK, the runway (13R) is 14,511 ft. X 200 Ft. TO normally would be at 133.9°.

The LAX runway is 3,416 ft. shorter than that at JFK.

Are A380s limited to 200 ft wide runways for TO & landings?

If so, perhaps a fully loaded and fueled Qantas A380 departing LAX would require maximum thrust on TO (72K) at times, especially with an east wind blowing. TOs are always to the southwest. Full fuel loading would probably be needed to assure sufficient reserves non-stop to Sydney, head winds, etc.

Any thoughts?

Turbine D
 

As you surely know, there are 2 more RWY´s at LAX, 24 L + 24 R. Both shorter than the southern pair and therefore not used, I assume. At least it wouldn´t make no sense at all to use a shorter runway if a longer one is available with these heavy departures.

RWY width of 200 ft. used to be the limit at the very early stage of introduction of A 3800, but a while later the limit was lowered to 150 ft. The much greater limiting factor to runway use are the dimensions and lay out of the attached taxiways. I know of several airports that had to widen taxiways or at least the shoulders. Also curving radii where a case of concern.

Ref. downwind take offs, I thought the general limit to that kind of operation is set at 5 kts.

Hope this one works
Aircraft Characteristics
Than select A 380 and the .pdf file with all A 380 data will be downloaded.

Good morning. Looking for some input on Shaft interlinkage via vibration. HP seems to have had the most, and to have caused secondary vibrations. This is not a tri Shaft Isolate machine, Shafts share a common airspace, and at extremely close quarters. What caused the damage to the Stub pipe? Again, the bore/align may have been off, but the wear evident in the pipe's interior bore shows excessive amounts of bore expansion, vibration??

Is vibration the source of damage to the HPIP structure?? Is it also due to insufficient strength causing flex in the diaphragm's field?What about the extra RPM's and Contra rotation?? Is there fatigue here? Are the bearings susceptible to damage and axial drift due wear from vibration and vibration instigated lack of oiling??

Bearfoil - Have we had confirmation that wear was present in the stub pipe? You seem to be pretty convinced but I haven't seen a single supporting opinion.

Was the HP/IP structure damaged prior to disc burst?

Most likely scenario remains oil fire leading to disc release and overspeed to burst.

Lawyers and machinery, a fictional account.
 

RR: It was just a stub pipe. It’s fixed, you’re good to go.
Q: Wait a minute. You see our lawyers have said we have to be sure that everything’s ok before we fly again.
RR: It is. Have a nice flight.
Q: Yeah but, the thing is, we grounded the whole fleet you see.
RR: You did what?!
Q: Well, you know, we need to know it’s safe to fly. The lawyers say we gotta know stuff.
RR: What stuff?
Q: About the A, the B and the C mods. Component life times and all that.
RR: Yeah, well, we can’t go into details but we fixed that ages ago. The fleet gets gradually upgraded as we go. Don’t worry about it. Have a nice flight!
Q: Yeah, but, you see, the lawyers are telling us, well, they’re not quite sure why we grounded the fleet, and now we need reasons for doing that and more reasons for flying again.
RR: Right. Erm. Ok, have a nice flight!
Q: Uh!
RR: I’m not sure we can help you with that one sport.
Q: Well, you know, it’s the lawyers; you gotta help us out here.
RR: Look here old fruit, we’ve got lawyers too. It’s like this. It’s a standard defence. You sue us, we shut up. Have a nice flight.
Q: Gulp! ……………. Fire up the engines!

I hesitate to get into speculation about what did happen in a specific incident about which somebody else holds all the cards of evidence knowledge and all I am providing is ignorant speculation.

But from a general sense :)

Parts not meeting design specifications are prone to early wear-out modes from even normal engine operation including temperatures and vibrations.

Fatigue itself is a wear-out mode to me. Left long enough a crack grows to a point where it opens up and squirts oil.

Failure conditions themselves often lead to cascading collateral damage. Thus a disk failure that doesn't clear the engine in a few miliseconds is sure to mess up its rotor drive shaft and bearings.

Chicken and egg questions are the challenge to the investigator and require postulations, experience, and lots of eyeballing of minute damage to confirm. Any one person is sure to get parts of the scenario wrong, so a team approach with pro and cons works best to establish a meaningful corrective action program.

lomapaseo

I have always (three years worth), held utmost respect for you and your work. From the first reading of your TWA800 Paper, I noticed you have a keen grasp of traditional approaches to questions proposed re: Failure mode/chain fail.

If you have read Shakespeare, you might discern the meaning of my internet name. Your style is, well, predictable, if I may say. You are frankly what is known in the old english as a scolde. You never fail to expound on the rather dated approach (IMO), to investigation. There is no disagreement with your post, but for one issue. Ignorance. Ignorance is a straightforward word that has a multitude of definitions. Suffice to say that I do not consider myself ignorant here, in the way you may mean.

Engine failures propagate, they may start small, and perhaps minor, but without attention they involve increasingly the other interrelated systems and components (modules). The Disc Burst did not just "happen". Neither is the Oil Fire the single Bullet theory that so many would have us believe. From the first T/O on the 380 wing, the 972 started to self destruct, as opposed to simply wear down, or out.

So did the 700 Edelweiss incident. Not due to lack of prescribed maintenance, or bad fuel, or Oil. This engine family is a Formula One engine in a Chevrolet. You will excuse the Automotive reference, but in racing, a powerplant has only to excel for a short time, its life is measured in shorter terms, and success is measured in a win, and likely retirement of the entire engine, all of it.

The TRENT is marketed as a lightweight, it is well known to weigh at least a ton less than its competitors. This is eight thousand pounds of increased useful load on a four engine a/c like the A380. Over time, that is a remarkable amount of increased profit, remarkable profit Also the brochures will tout its "Modular design", allowing for shorter turns at checks and strip. Unfortunately, Qantas was told that to retain its advantaged position due light engine weight, Thrust would need to be augmented by that ton to get an additional six tons of hitherto undiscovered weight off the deck from California to Sydney. Still with the advantage, by the mere addition of a keystroke, and not a single change needed on the Engine !!

The Fan is a new design, its shape still being fought over with a competitor. It presents new challenges to an existing design. The Fan has a "fuller" disc and drives more air, more efficiently. How completely was this Fan tested relative to new challenges? Perhaps not as completely as it should have been, with data being misunderstood or even actively ignored?? Please note the vibration reads on the failure of the IP disc on Number two. As N1 and N2 dropped, what was the IPT doing? You should know this, do you?

Finally, there is a format of incident investigation that is being used in rooms across the globe. You could google. First know this: The enemy of the Truth is consensus.

Agreement in and of itself is the enemy of discovery, so I would make reference to your mention of "teamwork". The new deal is confrontational dialogue, not in the sense of rudeness, but in the sense of exploration. It has been in use since I learned of its development at a University in California, well, a long time ago. It does not fail.

Humans think that to collaborate is good. In most things it is. It is an instinct, and like most instincts it has a place. It does not have a place in the Boardroom, or the Investigating table. Confrontation (non-physical, of course) brings to bear (!) a primal clearing of inputs and data (but not exclusively!), while one proponent can excise a nugget of new that has not been entertained because it cannot pierce the traditional paradigm of................consensus. Attacking a problem together can have unwanted results when compliance and social desires trump a good fight.

It is a long and interesting (to me, anyway), discussion. The player in the exercise who forms the wall the Truth can bounce off, is the foil, the one(s) who will fight to keep agreement at bay, and investigation at its highest expression. Please don't do anything differently. and I should not tell you this, but I enjoy greatly when you are at your most righteously snarky.

Thanks for the treasure trove of information on the A380, it will keep one busy for quite awhile studying it all.

Re: LAX - I was aware of the 2 northern runways. But, for the A380, they don't work because the taxiway (24L) is too close to the runway and must be cleared of all planes during A380 operations. The first Airbus A380 into LAX actually landed on 24R in 2007.

The airport spent $88M to widen turnoffs and build a new cross taxiway at the western end for A380s landing on 25L from the east. This may be visible from the Google map, if it is up to date.

Also, the 25L/7R runway was widened to 200 feet so that the outboard engines of the A380 didn't overhang in the grassy areas leading to potential FOD damage.

"The player in the exercise who forms the wall the Truth can bounce off, is the foil, the one(s) who will fight to keep agreement at bay, and investigation at its highest expression."

First one to say "Best Practice" gets promoted! :rolleyes:

bearfoil
This is an old article, but, it is the same Qantas A380 that is parked in Singapore awaiting repair disposition. I wonder which engine it was at LAX?

Qantas A380 grounded in Los Angeles - Travel - smh.com.au

I really must strongly disagree once again. Not formula one, not lightweight in the sense you mean. The difference is three spools, the design goal since the sixties being efficiency and compact design at the expense of greater complexity over the two spool turbofan. It has taken Rolls Royce a long time to achieve the weight advantage it presently has but it is in no sense a fragile piece of equipment. Think robust instead. The technical advantages of the three spool design grow with engine size.




Give me strength!!

Bearfoil = wrong, dead wrong and completely and totally wrong.
Truth = start by reading the ATSB preliminary report.

From experience, the runway utilisation at LAX usually has arrivals on the outer pair (24R and 25L) and departures from the inner pair (24L and 25R), so landing 24R would be not unusual.

Maybe a better question is where do the QF A380's normally park at LAX? Do they still use the Tom Bradley international terminal, and if so which stands are A380 suitable?

I understand the taxyway issues with the A380, it could be that the parking location determines both the landing runway and departure runway assignation. For example, if they use Tom Bradley northern end then 24R for landing and 24L for departure probably interferes less with other taxying traffic; conversely the southern runways for parking TB southern end.

The northern pair are, however, shorter in length, and hence may be the cause of the requirement for rated thrust usage rather than some degree of derated thrust.

digging mud ??
 

Found the attached message digging in all kind of messages probably containing something called" the light at the end of the tunnel"
Rolls-Royce Bearing Box Blamed in A380 Engine Fire

I am looking foreward to your comments

Annex14:
From the article.
And the date of this report is?

Goodness!! What's a poor ignoramus supposed to do with this?

The bearing failure, slop, flop and buzz, allowed the IP Shaft to "migrate" aft?? Isn't that what AD's are for?? So much for a duff stub pipe. Unless, unless, it was the one lubing the ball bearing thrust snubbers at IPHP. Not the one lubing the Rollers?? Tickle my arse with a feather.

Vibration, vibration, vibration. Location location location.

Question then. What of the bearing boxes in the 900?? How about in the X ?? Highly strung fuss budget? Or Gorilla meant for decades on the wing.?? You make the call.

first floor

The date is important, and more important is the nature of the Failure. When is it not allowable to organize one's thoughts around a year's worth of documents and inspections?? Jump ship because a highly suspect corporation wants to pin this disaster on a piece of tubing??? It was not Ian at the bench with a hangover. My prediction is that RR will regret having tried to mislead, and keep secrets relative to Safety. Power by the Hour is nifty, if both parties are honest, and not bent on protecting their personal hides because they've pushed the Camel over the cliff. The Camel didn't die, and he is quite pissed.

bearfoil

where's old engineer and Turbine D when they are well and truly needed.

firstfloor
 

Sorry, don´t know. Got it via this Home page : Ball Bearing, Roller Bearings & Power Transmission Distributors Manufacturers Community For SKF Timken FAG INA NSK
There it says : News and thereafter one can click on each of the brands named in the list. In that SKF list it´s report Nr. 2

just another one . . .
 

Page 31 ATSB Preliminary Report

Other party safety actions >>> Qantas

Quote:
3. Before further flight, carry out a borescope inspection of the bolted joints of the HP/IP [High Pressure/Intermediate Pressure] Support Structure area of each engine per RR NMSB G592.
Any connections to >>>540 Psi at P30 ????

Must admit, only after the probably 6th or 7 th time reading that report I struggled across this statement.

I think probably due vibration due to wear/loose tolerances, or Vibration alone, or a resonant frequency. Wonder how the Ball Thrust box was found and hung on the case post engine removal??

bearfoil - Annex14 - firstfloor
Humm, Thinking!

It would appears that we are back to the proposition: A leads to B, B leads to C and C leads to D, C = fire, D = BANG! The questions are: What are A & B, Is there A & B or just B or is it even more complex A1, A2, B1, B2, etc.

The visit of the Airbus CEO to Southeast Asia no doubt was prompted to see first hand and be briefed on the damaged aircraft in Singapore. He then probably went on to Sydney to meet with Qantas leadership to further discuss the matter as a good aircraft supplier would do with a good customer. Now if his interview only took place a week after the event, there wasn't enough time to state with certainty the actual cause of the failure, but maybe only generalities or suspicions, perhaps from technical difficulties plus modifications being made with Trent 900 engines, i.e., SIA and Lufthansa and ongoing mods at Airbus.

Here is the timeline of events as reported by the ATSB:
11/4 The "event" takes place
11/9 Flight crew interviews
11/9 Start of aircraft examination
11/11 Aircraft examination continuing, crew interviews completed.
11/12 Recovered disc section sent to UK/RR for examination.
11/13 Engine successfully removed from the aircraft.
11/17 Engine dismantling at a workshop in Singapore with the LPT module being removed to gain access to IP turbine damage area.
11/22 Parts of interest have been photographed and sent to UK/RR for further examination.
12/2 Stub pipe announcement is made with a photograph of fatigue fracture.

So I think the Airbus CEO "interview" and reporting of the same is not in the right place on the time line for any conclusive cause to have been made.

Which one? Are there two? The one of suspicion would be the one between the HPT rotor and the IPT rotor which contains the plenum chamber where the oil lines feed and drain the roller bearing box. This is also where I think the stub pipe location is.

I am having trouble believing the IP shaft could move back hardly at all without scoring the LPT shaft where it flares out going aft. There is not enough room there for this to happen without seeing the effects which are not in evidence in the photo of the removed LPT module.

Obviously, it sure would be nice to see the compressor areas of the engine to know all of this for certain.

Firstfloor - I loved you fictionalized Law vs Machine dissertation,LOL:), but probably not far from reality.