Olympus help request (from TVOC)

[Gully]

This was posted by Oberon over on TVOC's forum this morning:

As most of the readers of this forum may realise, we have a corrosion problem with some of our Olympus engines. We have no publications that relate specifically to corrosion problems with this type of engine. We are at somewhat of a loss to explain how this corrosion came to be, considering the low flying hours that we did last year, so we are appealing to you guys for help.

There may be someone out there who has had experience of working at COMART at Waddington (Command Olympus Modification & Rectification Team (I think)) or there may be someone who has worked at Rolls Royce Aero on the repair line, and has retired.

We need to understand the problem, the causes of the problem and the potential solutions so we would like any of you who may have experience of 2nd – 4th line or civil repair to contact us. We feel that if we could form a discussion group, utilising the vast experience that is out there, then we would be able to not only solve our current problem, but would be able to put in place preventative measures to ensure that we can prolong the life of our most valuable assets.

If you, or anyone that you know, has the knowledge that we need, I would ask that you either reply to this posting or PM me with details.

Many Thanks


Oberon
Vulcan Engineer

[Saracenman]

has anyone posted that appeal onto Prune?

Prune's 'network' tends to be quite effective!

sm

[Gully]

has anyone posted that appeal onto Prune?

Prune's 'network' tends to be quite effective!

sm

Not that I'm aware of and I'm not a registered Ppruner!

Gully

[Old Rigger]

I have answered over on our other forum but if I have not been beaten to it I will post on Pprune in a minute.

[Mackrick]

The thing to remember from Oberons post is that this is way down inside the engine and not something you can get at (to take a sample) without stripping the engine in a bay environment. Boroscopes are a new thing and not something that was around in the service days of Vulcans. As stated in the post this is something new and would never have been picked up by the 1st line guys or crew chiefs only in 2nd - 4th line or back at industry.

Made a few calls today after speaking to Oberon to see if any of my contacts can shed any light on the issue. If I get any answers I will let them know.

[Mayfly]

I suggested trying the crew chief register or the squadron associations, not sure how much help it will be

[Gully]

I've PM'd Obi with the suggestion that they approach Alan Baxter, author of "Olympus: The Inside Story" for RR Heritage publications; a former RR employee involved with the Olympus development programme over many years.

Gully

[Old Rigger]

Decided to pause on posting on Pprune untill I have a response to my PM to Oberon as well

[Mackrick]

Just spoken with a close friend (Rolls Royce Rep) who has a few thoughts on this and is going to ask a few other Reps (Ex Scampton engine bay men) to see if they come up with the same thoughts as his.

[Bovril]

655sooty... can you help , plus one of our guys works for RR, but i thing TVOC will have already spoke to that department

[Crew chief]

Hi all.

Correct me if i'm wrong but 558 has only three remaining good spare engines.If rolls say the three with corrosion are u/s then 558 has no spare motors.If the spare three are fitted and 558 has more engine issues then its game over.

[Dougs]

time to squeeze 4 off EJ200's in then?
one can dream

[Gully]

Hi all.

Correct me if i'm wrong but 558 has only three remaining good spare engines.If rolls say the three with corrosion are u/s then 558 has no spare motors.If the spare three are fitted and 558 has more engine issues then its game over.

Not seen anything confirming the number of engines affected by the corrosion. It has been specifically asked over on the Vulcan forum, but without a response. Although Sad Sam's comments last week seemed to indicate that 2 may need changing this week?

I believe the engine removed last year is still under investigation, leaving 3 remaining as yet unused engines.

Gully

[Crew chief]

Hi all.

Give the boys at southend a call.XL426 is not far from the sea and see what they use to keep corrosion at bay.

[Gully]

From Oberon this morning...

Thanks for the advice & PM's guys. Have passed them along to the chaps at Bruntingthorpe for action (Oberon at home babysitting granddaughter today) Just an aside - I found a procedure for carrying out compressor washes the other day, where you squirt a mixture of demineralised water and paraffin into the engine (3 gallons worth). This is done while the engine is ticking over and gives it a good old seeing-to. The chaps from Ansty (marine Olympus experts) told us that if we were then to squirt WD40 into the engine, then the residual water mixture would be dissipated and the WD40 would bake onto the blades due to the engine temperature, et voila - loadsa protection.
However, the reason that we did not do this is because the AP states that Compressor washes are only to be carried out when the power of the engine falls below a certain limit. The graphs & charts in the book give you all the info on how to calculate this limit. As we have had no problems with engine power, we have not carried out these washes. With 20/20 hindsight, maybe we should have been doing this at regular intervals but as you all know, we work "by the book" and if it says don't do it, then we don't. We would have to have procedures amended in order to carry out compressor washes at regular intervals despite engine power not being an issue.

Oberon

[Saracenman]

well let's just keep our fingers crossed that RR are happy with the suggested new procedures - buggered if not!

thanks for keeping us informed Gully

sm

[Old Rigger]

Had no response to wether they want to try anyone from Pprune so won't bother. Additionally I have asked wether they have removed any corrosion to see wether they actually have a problem, but no answer.

I also added that it does not matter how it got there, so why waste time and angst over the how, it needs removing using any of the modern chemicals/equipment designed for this very purpose and then see if there is any damage to the item that has indications of corrosion, if there is then see what existing limits there are and then make the decision as to how to rectify the situation and finally use one of many existing and allready suggested methods of stopping it coming back or in those unaffected engines appearing in the first place.

[Mayfly]

From Oberon this morning...

Thanks for the advice & PM's guys. Have passed them along to the chaps at Bruntingthorpe for action (Oberon at home babysitting granddaughter today) Just an aside - I found a procedure for carrying out compressor washes the other day, where you squirt a mixture of demineralised water and paraffin into the engine (3 gallons worth). This is done while the engine is ticking over and gives it a good old seeing-to. The chaps from Ansty (marine Olympus experts) told us that if we were then to squirt WD40 into the engine, then the residual water mixture would be dissipated and the WD40 would bake onto the blades due to the engine temperature, et voila - loadsa protection.
However, the reason that we did not do this is because the AP states that Compressor washes are only to be carried out when the power of the engine falls below a certain limit. The graphs & charts in the book give you all the info on how to calculate this limit. As we have had no problems with engine power, we have not carried out these washes. With 20/20 hindsight, maybe we should have been doing this at regular intervals but as you all know, we work "by the book" and if it says don't do it, then we don't. We would have to have procedures amended in order to carry out compressor washes at regular intervals despite engine power not being an issue.

Oberon

I think the quote above says it all - if its not 'in the book' they need permisson & have procedures amended to do it so not as straight forward or as easy as it may seem

[Old Rigger]

Accept that Pam, but corrosion removal to see if there is actually a problem is all standard repair manual stuff, and to use a newer chemical or technology for existing removal and prevention methods has allways been permitted, primarily due to changes in H & S rules and improvements on equipment that makes the old stuff obsolete that came about with knowledge. The reference they gave does not say they cannot do compressor washes it just says you do it for a particular reason i.e. loss of engine power, but if it would prevent this problem in the future it should be down to the engineers in charge if they wish do it more often than stated, it is most other places.

Additionally if that was the rule set that is going to be applied then why did they boroscope the engines as I bet that is not in the original APs, new equipment finding problems that technology from the APs back then possibly would not find, so if you are allowed to use new technology to find problems then you can certainly use new technolgy to fix what it finds.

For example the original APs on an aircraft state a certain chemical to clean, then another to penetrate a crack and another to see the crack or a UV light depending on what type of crack detection method you are doing most of the chemicals are superseded and made by another company, the cleaner is banned under the Montreal Protocol and the UV light has been superseded with a better, safer more compliant version, but if we employed that stategy here that the book does not say we can do that, we would never fly an aircraft again.

Its what happens on most aircraft, additionally if you want to see what acceptable corrosion looks like, try to get a look at the CFM engines for one, a few of the repair manuals have NL against corrosion which stands for No Limits, which means as long as the item is structurally sound,which it can be even if corroded, it does not matter how much corrosion is on it or how cosmetically awfull it looks. This is dependent on what part of an engine or airframe the corrosion damage is on of course.

[RLN]

What OR said, but it would be nice to have a sample chemically analysed to prevent it happening again. We wash our Gas Turbines every week, and this is far more frequent than Siemens recommend. We do it for efficiency, but to prevent corrosion (of whatever type) happening again it is worth it. Just keep the concentration of any chemicals at a minimum.

[Gully]

Also from Oberon:

Similarly, there appears to be evidence of rust, where there are no ferrous parts, but unfortunately, these are so deep in the engine that they can only be seen by boroscope and we can't take a physical sample without breaking the engine down. Hence that is why we are asking for input from people that are older (maybe) and wiser (definitely) than we are, who may have seen this phenomenon before.

The chap from Olympus Aerospace (no relationship to engine - think cameras), who boroscopes different types of engine on a daily basis, is as perplexed with the symptoms as are the Marshall Aerospace and TVOC Engineers.

Sampling and testing the deposits found via the boroscope inspections does not appear an option (unless some form of keyhole surgery tool were to be used?).

Gully

[Old Rigger]

If there is brown staining where there are no ferrous metal parts then I would hazard a guess that it is sediment from evaporated water, which tends to leave what looks like corrosion or rust if you wish, I have seen this before.

Again a recent example was a design query was submitted for what looked like a mixture of ferous and aluminium corrosion in a hard to reach part of the aircraft and it turns out that the majority was accumulated dirt/dust that had become forced into the comparment corners, I have yet to find out if under it there was actually any corrosion.

As to getting samples, I am pretty sure that nowadays there is equipment out there that could do it, but is it really necessary, if you have to strip the engine down to remove and treat the areas then that is the time to analyse what type, as in over 40 odd years on & off, of dealing with aircraft corrosion I have never been asked to provide a sample to be analysed.

[RLN]

I was just thinking of the sample as a nice to have, but certainly not at the expense of a strip. Wash the engine(s) and boroscope again to verify that it has gone, and see if there has been any corrosive effect or was it just a deposit. If they really wanted to, I'm sure they could collect the wash water and analyse that to see if there is anything there that shouldn't be. It can be done, but in this case probably not worth it.

[Mackrick]

While seeing the area is one thing access is another. Even if a sample could be taken then treatment would be another issue in a place you can't get to. Engine removal then stripping would cost money, as would a rebuild and dynamic runs prior to fit. Precautionary treatment would prevent this from happening in future but we are talking about new procedures for the Vulcan so again this would cost. Adding silica gel / vapour barriers in the intakes would help when the engines are not to be run for some time. Inhibiting the engines could also help. Also Boroscopes where never used in service on the Vulcan. Remember that 558 is not being operated in the same way that the it was operated while in service so new issues like this are bound to show up.

I have a few leads that have been passed on to Oberon and Co but still asking around.

[Old Rigger]

Macrick, agree about cost et cetera. I am pretty sure there are modern chemicals and the equipment to apply it that can be used to remove whatever it is and then re boroscope, if fluids got in to cause the deposits then fluid can be put in to remove them and then keep them out. There might be specialists firms around these days who would possibly take this on/loan the equipment, at little or no cost to have their name added to the wall of fame etc. if approached correctly, allthough a quick search does not throw any immediately up. I still cannot see how places like RR etc do not have engine corrosion specialists, it should not matter that the engine has little data left available or what type of engine it is or how old it is as it is as far as contruction materials and basic design goes, corrosion is caused by exactly the same reason, with the same type of residue, gets into the same places and should be fixable etc in exactly the same way that it is done nowadays.

I could understand if someone said we need a new turbine blade but cannot build a new blade as we do not have the design drawings and could not make it out of exactly the same material, so the engine turbine would probably not be able to be balanced and the expansion/contraction rates would probably be totally different so could possibly cause vibration and destroy the engine. Even if possible this would be really expensive and would take an awful long time even if someone was prepared to try.