Location Location
 

If the engine had expolded over Manhattan I bet the FAA would be a little more vigorous in giving out the all OK tickets. CNN would have made a few noises.

Regulations & Guidance Circulars
 

Trent 972
If you refer to the master certification document:
PART 33—AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES
You will note under "vibration", it basically states (my wording, not verbatim) that adequate testing must be done to demonstrate vibration is not a problem. So then, the circular about this subject is issued to "guide" the requester through the process of testing for vibration during the certification process as there may have been many questions in past and present regarding what is acceptable to the FAA. The circular implies "Here is a way to accomplish vibration testing that is acceptable to us, but there are other way that may be acceptable as well." It is a unhappy day to have spent $1M or $2M on an engine test to only learn it didn't meet the certification criteria in the FAA's eyes.

Turbine D

Thankyou Turbine D.
Please provide the documents to prove that
Was NOT done.

I would also like to see the document from the FAA that informs
After I've had a chance to read them, I'll be more than happy to discuss the ramifications.

Trent 972 - there isn't. Overactive imaginations are running free.

Why all this discussion on FAA on a European designed engine fitted to an Australian aircraft anyway?

DERG

Refer to the Operating Instructions for information on approved oil specifications for the Trent 900 old chap.

Shoulder to Shoulder
 

"Why all this discussion on FAA on a European designed engine fitted to an Australian aircraft anyway?"

This might be a dog eat dog industry Shell but when it comes to life and limb we are united.

Trent 972

Electronic Code of Federal Regulations:

From this document:
Subpart E—Design and Construction; Turbine Aircraft Engines
§ 33.63 Vibration.
Each engine must be designed and constructed to function throughout its declared flight envelope and operating range of rotational speeds and power/thrust, without inducing excessive stress in any engine part because of vibration and without imparting excessive vibration forces to the aircraft structure.

Subpart F—Block Tests; Turbine Aircraft Engines

§ 33.83 Vibration test.
(a) Each engine must undergo vibration surveys to establish that the vibration characteristics of those components that may be subject to mechanically or aerodynamically induced vibratory excitations are acceptable throughout the declared flight envelope. The engine surveys shall be based upon an appropriate combination of experience, analysis, and component test and shall address, as a minimum, blades, vanes, rotor discs, spacers, and rotor shafts.

(b) The surveys shall cover the ranges of power or thrust, and both the physical and corrected rotational speeds for each rotor system, corresponding to operations throughout the range of ambient conditions in the declared flight envelope, from the minimum rotational speed up to 103 percent of the maximum physical and corrected rotational speed permitted for rating periods of two minutes or longer, and up to 100 percent of all other permitted physical and corrected rotational speeds, including those that are overspeeds. If there is any indication of a stress peak arising at the highest of those required physical or corrected rotational speeds, the surveys shall be extended sufficiently to reveal the maximum stress values present, except that the extension need not cover more than a further 2 percentage points increase beyond those speeds.

(c) Evaluations shall be made of the following:

(1) The effects on vibration characteristics of operating with scheduled changes (including tolerances) to variable vane angles, compressor bleeds, accessory loading, the most adverse inlet air flow distortion pattern declared by the manufacturer, and the most adverse conditions in the exhaust duct(s); and

(2) The aerodynamic and aeromechanical factors which might induce or influence flutter in those systems susceptible to that form of vibration.

(d) Except as provided by paragraph (e) of this section, the vibration stresses associated with the vibration characteristics determined under this section, when combined with the appropriate steady stresses, must be less than the endurance limits of the materials concerned, after making due allowances for operating conditions for the permitted variations in properties of the materials. The suitability of these stress margins must be justified for each part evaluated. If it is determined that certain operating conditions, or ranges, need to be limited, operating and installation limitations shall be established.

(e) The effects on vibration characteristics of excitation forces caused by fault conditions (such as, but not limited to, out-of balance, local blockage or enlargement of stator vane passages, fuel nozzle blockage, incorrectly schedule compressor variables, etc.) shall be evaluated by test or analysis, or by reference to previous experience and shall be shown not to create a hazardous condition.

(f) Compliance with this section shall be substantiated for each specific installation configuration that can affect the vibration characteristics of the engine. If these vibration effects cannot be fully investigated during engine certification, the methods by which they can be evaluated and methods by which compliance can be shown shall be substantiated and defined in the installation instructions required by §33.5.

[Doc. No. 28107, 61 FR 28433, June 4, 1996]

Hope this helps...

Turbine D

Shell Management

1. It is believed that the FAA & EASA have similar requirements on aircraft and aircraft engine certifications. Both agencies talk to one another and accept back and forth certifications depending on where the aircraft/engine is being designed and built. In the case of the A-380/Trent 900 series, the ball is in EASA's court. In the case of the A-380/GP7200, EASA certified the aircraft, FAA certified the engine as it was developed by GE/PWA in the US.

2. The aircraft is not "Australian", it is of European origin, an Australian airline bought the package (A-380/Trent 900 series) as did other airlines.

3. The FAA accepted the certification packages, but probably depending totally on the EASA's certifications without much ado. No US airlines have purchased A-380/Trent 900 series aircraft. However, for flights into and out of US airports, a comparable FAA certification must exist or there wouldn't be Sydney to LAX flights.

4. Living in the US, it is easy to obtain FAA certification requirements as presented in previous posts. EASA certification requirements are not so easy per-se, perhaps you might contribute similar EASA documents for comparison.

5. The Trent 972 failure on the Qantas A-380 was not a ho-hum event. Anytime a disc bursts out of the engine, it is life threatening. And so, how did this happen? Was it preventable? Were problems identified, leading to this catastrophic event, not fully addressed? Why is there disassociation between what happened on Qantas verses seemingly prior related problems which were either partially addressed or not addressed at all at the time? What were the roles and responsibilities of the various players involved? How have they met their responsibilities?

6. Isn't this what the Tech Log is all about, exploring the possibilities?

So what oils are approved for the Trent 900 series engines? It isn't clear in the Type Certification Document.

Turbine D

To ask these questions is one thing. To answer them without the benefit of knowledge is another.

HN39
 

I wouldn´t be too sure that within the "Brotherhood of PPRuners" there are not some members that have the right answers at hand.
But to use and rephrase your words:
To ask this questions is one thing. To answer them in public might be of such an extend to the players involved, that it is wiser to handle the case with care and caution.
As I understand the ongoing discussion. Primary goal is safety. As an - important - side effect, we all want to hear from the "officials" what the root cause of that QF 32 desaster was. Well, we can wait.

For starters:
EASA Home Page

CS-E

Trent TCDS E.012

The Certificate is based on Data. Ignored or unaware, the applicant needs to supply this data. It is forthcoming. The bottom line is Spline Wear. The engine had an oil fire in test. The engine exhibited some anomalous vibration and resonant transients that beat it to a pulp over shorter than allowable (and Certificated) time.

These are the issues, and the rest is corn soup. Who expects a problem of this magnitude to casually enter the Public Domain?? Nice discussion, though.

Thanks for posting the EASA sites!

Engine oil
 

Turbine D has drawn a little heat for asking some questions, in the last few posts above. But nonetheless one of Turbine D's questions was of considerable interest to me, that regarding the specifications of the [QF32] engine oil. And Turbine D asked that question directly to Shell Management, whom I think we are entitled to assume has the background to answer it more fully than he did. The exchange:

Question:
Answer, by Shell Mgmt, addressed to DERG:
Well, I see now the question was DERG's, restated by Turbine D. I find the answer to be a bit circular, at least to me in my ignorance. The AC Captain who posted in the original oil thread here that he'd been down the AC oil road once before and never wanted to go down it again has my full sympathy. I too have been down the oil road with the oil manufacturers. But here goes, yet again and ever hopeful:

1. The type certification document says that the oil shall be as specified by the manufacturer. [I omit mention of the reams I read as to which manufacturer [AC or engine], and as to whom holds the certificate, and whom incorporates it by reference; not to mention where the oil may be obtained.]

2. The AC manufacturer now says that MJO II or MJO 294 may be used; the AC QF32 was shipped with MJO II installed; the failed engine appears to have been using MJO 294 [I may have to correct the "memory item" 294 on edit]. When the changeover occurred may have been at the 3-year repair point, but I did not see this published anywhere. Some or all of the other engines on QF32 continued with the originally installed type of oil.

3. Now comes the problem. Perhaps the Operating Instructions contain the actual specs of the oil, which is only identified by name in the public documents. [My deduction at the moment is that the A380 Operating Instructions either are distributed need-to-know basis only, or do not yet exist.]

4. Of course, the Mobil (or ExxonMobil, which may or may not be the same thing) website for oil contains the specifications for the oil in question. The problem is, these voluminous specifications are next to useless in the jet engine context. I give one example at #5 and 6 ff:

5. Viscosity of the hot oil: 5 centistokes at 100-degrees Centigrade. Well, I don't think the viscosity at 100-C has been of any interest since pressure radiator caps were added to water-cooled automobile engines sometime in the 1930s.

6. What are we given instead: MJO-xxx (whatever) is provided with extended range viscosity stabilizers. Give me a break. What is the viscosity of these two oils at 180-C and 196-C?

7. On to another question. What is the base stock of these two oil types? Well, for MJO II it is fairly clearly identified as a highly refined mineral oil base. Okay, I'll accept that as an answer. But for MJO-294, the situation become murky indeed. It was identified on a document posted here [at least of quasi-official standing, I will look it up] as being an HPC oil. However, I located a MIL spec discussion in which MJO-294 [number from memory, will edit] is identified as an SPC oil, which whatever it is, is not an HPC oil.

8. I think the MJO-294 must be also a highly refined mineral oil base, but with the addition of PG additives, but what do I know? ExxonMobil describes it as an "advanced oil", IIRC.

9. The question of whether both these oils have a mineral oil base bears on two questions. One is the question of lubricity, at which the mineral oils excel. The other is the viscosity buildup that occurs to such oils when the evaporation rate removes the lighter fractions preferentially, and "topping up" is frequent. It will be frequent if the operation is at the specification operating limit temperature for evaporation-- a 12-hour flight to LAX would consume half the contents of the engine oil reservoir.

10. ExxonMobil have an HPC oil under development. It is unobtainable in the US as of December, if it is available anywhere.

11. I get the feeling there is a desire to have the oil last between major off-wing inspections/overhauls. Perhaps this is because MJO-294 (again, number subject to edit) is a potent orthophosphate insecticide. For crying out loud, even the US tv police sitcom "Castle" took notice of this within the last month. Where do these people find these things out, let alone accurately? [That's not a question that needs an answer.]

Shell Management, I assume you must know the answers to the questions and uncertainties I discussed above: Meaningful viscosity data, base oil and expected T-972 oil temps enroute LAX as it affects viscosity buildup due evaporation on the long-term hand, and viscosity loss at high temp in new oil on the short-term hand-- these are the uncertainties which I think need to be known. It would be helpful to know your views on oil change intervals. Your views on whether Engine #2 might have been operating with an oil likely to have insufficient lubricity would also be helpful.

Hopefully you will not be constrained in your position at Shell from discussing Exxon products. Or you might prefer to make a discussion from the standpoint of Castrol products, which perhaps are more likely to have been used by RR in the development of the engine. Thanks.

Old Engineer
 

Thanks for that R and R outage away from the tough stuff. I have to say that my question to Shell would have been in the circumstances where I had him physically up agin a wall.

The oil sellers annoy me. I have done a fair bit of tribology and the best lubricant on the planet is nature's olive oil.

You can "crack" imineral oil all you want..comes nowhere near the mighty olive. I am so glad I am nowhere near Shell, I am very short tempered.

Approved Jet Oils per SAE 5780
 

Old Engineer

In this presentation, there is a table listing the approved oils meeting SAE 5780 specification requirements, BP, Shell & Exxon/Mobil.

http://isoclean.net/uploads/GE_turbi..._pres_STLE.pdf

By the way, are roller bearings more sensitive to oil viscosity changes at higher temperatures than ball bearings?

Oh dear. Some people are jumping to very big conclusions and suffering from homo-erotic based fantasies too.

BTW the Operating Instructions are for the Trent not the A380.

Shell Management

Thanks for this information, we knew this.

TurbineD

When you say:


Are you using the 'royal we'?

If you R_E_A_D the thread tou will notice Old Engineer wrote:

Quote:

---

3. Now comes the problem. Perhaps the Operating Instructions contain the actual specs of the oil, which is only identified by name in the public documents. [My deduction at the moment is that the A380 Operating Instructions either are distributed need-to-know basis only, or do not yet exist.]

---

Shell Management

If you go to the Spotters Forum and look at the first thread, it contains this:
Spotters it has to be said are not always welcome in the professional forums, and for good reason, because some of them make a nuisance of themselves and upset the pros and natives.

Need more be said?

TCDS - Trent 900 Engine Series
 

I have a question on the TCDS:

http://www.easa.europa.eu/certificat...4-24052007.pdf

On Page 4, Item 4 - Equivalent Safety Findings:

• JAR-E740 150 Hour Endurance Test

What exactly does this mean? Did the engine not pass this test? Was a subsequent test performed and it passed? Was the test waived?

What is the opinion of this particular item?

Amen to that, but with all the posturing by folks with ready made answers and blame at hand who obviously don't have a clue, there is little sense in adding to the wasted bandwidth of this thread.


There is that "we" again. What some of us want who fly on this machine, is that enough is known to fix the problem so that it is unlikely to repeat itself. The details of design and certification are in the province of engineers who are tasked with the everyday job involving same. Asking Joe on the street corner to comprehend the design and/or certification and to add his two cents is a waste of time.

Thats' why we have a "Continued Airworthiness" process and the ability for the public to submit meaningful comments to this level of regulation.

So far from what I've read on this board none of the comments submitted so far would overturn this regulatory action.

What design changes RR or its regulators chose to make furthur down the road are theirs to make without public comment.

Turbine D
Link below to video. The answer to the 150 hour test can be found at the 3.41 mark. Took me 8 seconds on google to find it. (Perhaps it was all done in a sound stage and it's just another conspiracy). I'm still waiting for you to prove that the FAA wasn't happy with the Trent certification as you claimed yesterday. Posting decades old certification requirements
(PART 33—AIRWORTHINESS STANDARDS: AIRCRAFT ENGINES)
doesn't meet the standard of proof to support your claim made in the prior post.YouTube - Rolls Royce Trent Certification

There has been little band width wasted in this thread so far. I am sure the website proprietor is very happy with the numbers of visits this thread has attracted. There are a few of us who have persistently sought answers in this thread with reference to known information. If the Qantas accident had resulted in fatalities I would not be posting here.

Readers will notice this particular group does not discuss airframe and control problems that the Qantas accident involved. The goal here is to educated ourselves. Knowledge is power, as they say.

The A380 and the T900 series engines are very much in the public domain and as the MBAs would say "we are all stakeholders in this enterprise". Some of us in the EUR paid taxes that set up the EADS company. Those like me, in the UK, pay taxes that are redistributed to RR for research and development.

There could well be members of this forum who have personal pecuniary interests in RR....a pension from them or shares in the company. Others might be motivated by pride and are in denial about what happened in this case.

In response to Trent 972
 

Yes that video is informative. The Trent is a series of different engines and this example shown here is not the T900 series.

The argument some of us have is that the Trent 900, in the process of certification, used existing data from the test bed from previous Trent series engines.

As the FAA advisory states: if existing data exists then use it. The problem is that the DATA for the T900 is UNIQUE.

We want ALL the data from the T900 series made public so it can be be examined by the engineering community. WE, the concerned members of the public, want the data from that T972 which exploded.

I have no doubt at all that Rolls Royce has taken steps to make the engines in service safe. In so far as risk to the public is concerned, I believe that it has been minimised as far as possible.

Rolls Royce have a duty of care to the public and I believe they have acted since this accident.

Now as far the suggestion that has been made that RR and the regulating bodies can do as they please, that their business is private, strikes me as somewhat disturbing.

lomapaseo
 

Well Sir, good job !! Excellent bashing!! But, excuse me, what is the difference of such an entry compared to the cited opinion of "Joe at the street corner" ??
And if you have a problem with my use of the word we in my post, I agree we wipe it and replace that word with an I.

Yes, I take advantage of the "blessings of an outside observer" but yet I am as concerned about safety and the sequence of actions - or non actions - after this frightening engine failure as you seem to be.

It´s the doubts I have in that by you cited "Continued Airworthiness" process and the speed and vigour of necessary corrections to that engine.

Yes, Qantas is flying the A 380 again across the Pacific and - as was stated - using full power. But as far as I am informed that "disgusting" AD about the spline wear is still in force. That must be considered as a hint to the fact that the root cause of the engine problems isn´t resolved.

I agree in what DERG wrote, RR for sure has taken measures to make those operations allowed under the valid AD´s as safe as possible. But future will show wether or not that is enough. I have my doubts.

Annex 14
 

Jo

You have to realise that lomapaseo has a completely different philosophy than the general public. I can see English is not your first language. This poster is no fool as we can see in his post #306. So what motivates this poster to make a statement like:

"So far from what I've read on this board none of the comments submitted so far would overturn this regulatory action." ?

Well I would suggest that this poster is absolutely confident that the FAA and EASA has no power whatsoever in protecting the public from danger.
That the existing cosy relationship between manufacturer and regulator will NOT and MUST NOT be challenged.

Now this very much reminds me of a command economy and if anything has scared me even more than the "novel event" when the T972 exploded.
You will know these attribute well from the pre 1989 days in Europe. Now some might say that is an extreme anology, but others will recognise the political implications, where the State can no longer protect is people from the few.

The few being those "inside" the club. Those outside the "club" are often described by insiders as "self loading freight". Now sooner or later the SLFs get wise to those who have a genuine interest in serving the public and those who are there to abuse the trust given to them by the politicians.

Not unlike the Roman Empire.

Rolls-Royce PLC
PO Box 2000
Derby.
Phone - 01332 661461
Fax - 01332 661630

response
 

Derg
Thanks for clarifying. You guessed correct, there is a "mother tongue barrier" and even all these years in ATC haven´t overcome some shortcomings.
As far as my answer to lomapaseo is concerned I feel that "one gets what he gives" and I can stand that for my part of the story.

Trent 972

With greatest respect to your experts opinion, your confidence is impressive. May I cite old Mr. Lenin that once stated : Confidence is fine but Control is better!
Not that I want to question your inside view of events, but I am sure you are aware that the "spline eating cause" in those engines you use still needs to be removed. Or is there silently, without information of the public, a "D mod" engine in use ??
Please, don´t feel offended, no hard feelings!! I keep my fingers crossed for you and all of those relying on that technology.

Trent 972

I think you misunderstood what this comment meant, it wasn't a claim the FAA was unhappy. It was a statement in general to explain why the FAA guidance circulars exist in addition to the certification requirements. It is to prevent misunderstanding or misinterpretation of the certification process for certain elements of testing. Should this happen, a significant amount of money could be wasted because of a required "do over". These regulations not only apply to RR, P&WA and GE, who are very familiar with certification requirements, but other engine producers that may not be so familiar. The comment was not directed at the Trent 900 certification as you suggested.

Sorry if I confused you...

Federal Leverage
 

I tell you what Turbine D..if that engine had spewed out over NYC the FBI and NSA would have had that data within 12 hours of the event. I am damn sure the FAA is very happy the Qantas A388 enters and exits over the Pacific Ocean. When it comes to NSA stuff it doesn't matter what admin is in 1600 Penn..they all tow the line.:cool:

RR comm contacts
 

... then the NTSB and FAA would have been involved in the same capacity as the authorities of Indonesia are in the QF32 occurrence.

I think, imho, that posting, reposting, and arguing about RR communications people and the relative political aspects of NTSB/ATSB isn't particularly helpful. All of the Public Agencies are political by nature, they rely on the experts for Data and compliance. The PR at RR have a disincentive to divulge proprietary Data to anyone, and if they aren't even aware of this sensitive data, what is the point?

I think the essence of this discussion has to do with Thechnical considerations. To that extent, I relish the give and take here, friend or "foe"; it is a novel and elegant way to gain knowledge without the burden of Semester Tuitions.

Oh Damn Bear
 

I was going to have a head long fling into the people behind this accident. Who does what in the company etc. If the major directors who perhaps had other interests that might conflict with the interests of RR and the EASA. The politics of international aerospace business. Aims and Objectives..that kind of stuff.

I am particularly interested in the decommissioning of the UK Ministry of Defence and how the people who worked there will take to the new job of saving people rather than killing them. That sort of stuff.:\

Turbine D
 

Ref. your question in post 388 about rollerbearings and sensivity to oilviscosity probably the added link may be of help ?? Not sure, but looked around and found this.

Speeds and vibration - SKF.com / Products / Interactive Engineering Catalogue/Rolling bearings

Hi. I think OE has said that rollers have more loaded area than an equivalent Ball bearing. Deep groove may be different? Is there "flattening" of the ball, to give a more "lens shaped" loaded surface??

Have we missed something?
 

If you look up "RB211-H63"
Does the clue to the T900 series troubles stem from this hybrid?

Right Guys a EUREKA moment
 

Please open up this

http://www.eng.ox.ac.uk/thermofluids...88,11,Existing Seals – current solutions

Now this will take a little time and unless you are a really dedicated:8 which I have to say I am, then skip the hard bits! The colours and design of this presentation is WONDERFUL so take the time. I must thank David Gillespie and Budimir Rosic from Oxford Uni Dept of Eng Sc.

It starts where is says THE BIG PICTURE

Go to THE SEALING CHALLENGE part

See the three cross sections of the shaft...with you mouse click on them...you see how the shape changes..that is why we have the spline wear and are losing the oil.

OK So how to fix!

See EXISTING SEALS

Now see THE NEXT GENERATION OF SEALS

EUREKA! That is the fix RR has done to the T900s..latest seal design.

WHOOPEEE!:)

All we have to do now is solve the excessive spline wear!:ok:

This is the patent detail of this seal:
Leaf seal, in particular for a gas turbine

Bearing Suppliers
 

From this we know that SKF, wunnerful bearings by the way, do NOT make the baearings for the 900.

SKF to supply main bearings for the new Trent 1000 engine from Rolls-Royce - SKF.com/Welcome to the news & events portal/News archive

this is unusual. It means the bearings are specials. The hunt goes on.:cool:

Who makes 'em
 

FAG supplies all engine bearing supports and numerous components for the Rolls Royce “Trent 900” engines for the world’s largest passenger aircraft."

http://www.schaeffler.com/content.sc...se_3343488.pdf

prestigious aircraft’s engine."

In this document there is also a VERY interesting report on fake bearings. We all need to read this.

http://www.schaeffler.com/remotemedi...5_03_gb_gb.pdf