AS350B3e aka H125 engine overhaul $$$
 

request please for some logical answers...... 2 x 2D engines; both reached 4,000hrs. One has 50% usage creep, the other 250% usage creep; what is the difference (if any) for overhaul???

Thanks for the answers

"Usage creep" being a marketing term for Low Cycle Fatigue?

I would assume this is in excess of a formula derived by TM as "normal" and the
percentage you have deviated from it.

i.e. The number of High Ng variations versus flight hours.

FADEC and EEC's are very effective at measuring this data and it is probably good for both camps i.e. end user and
manufacturer.

The wheels have a finite cycle life and may do more than one overhaul period if
the cycles allow it to be economic to put back in service.

You would not put a wheel with low cycles remaining back in unless it was your own
engine then the decision is yours.

What you need to decide is whether it is economic to strip the engine and replace a wheel
in the future before TBO. Keep in mind that during this strip the whole module needs to be serviceable on release and you
may have a few nasty surprises. Wear, damage, SB incorporation etc etc.

Power by the Hour programs can be effective but you need to review the "fine print" and it is not
for everyone.

Effectively you "lease" the engine for a fixed price plus a fixed price for your usage that may depend on how you use it.

If the engine has an issue which is not your fault it is replaced at the manufacturers expense (with a few caveats) and it can
be like continuous warranty.

Airlines for example don't "own" engines.

I have done this in the past with 1B engines and it was effective but the operation suited it and I could walk from the hangar
to the TM shop so.......................

In answer to your question - it depends.

What does TM say? That would be the first place to start. Let us know.

Hmmm.. My 2D knowledge is a bit rusty, so I had to crack open the MM.

The HP blade limit is 261%, and is the only item that looks to me to be covered by creep. I seriously doubt they would release that engine back to you without a new turbine wheel, especially at 250%.

The difference in O/H here would be that you'd be up for a new turbine wheel in that second engine. How much? It's been a very long time for me and I would have no idea how much it is worth now days.

As RVDT says, approach your TM FSR and straight out ask them the price of two standard O/Hs, plus the price of a new wheel on one engine.

Are you PBH? Or is the asset owned?

Thanks for the replies thus far. Company own the machines outright, no power by the hour engines. What we would like to know is the overhaul cost difference between these 2 engines (if any) @ 4,000hrs?

VF,

No disrespect but you will not get the correct answer asking on Proon.

As TM is pretty much a closed shop and there are a vast number of variables at
play - your TM FSR is your man.

In direct 1 + 1 equals 2 terms the answer to your question is probably yes the higher creep engine would cost more.

Then again you do not know the limit at which the wheel is mandatorily replaced at overhaul - maybe both are.

TM will know for sure - and I doubt they subscribe or would ever place that data in "public".

Hey RVDT

Have already tried TM & they are unwilling to give any clear answers, claiming it depends on many factors????

Hallo VF,

as RVDT said - you are not gonna get a more precise answer from TM. You will maybe get an estimate which will most definately change once they have the engine(s) and started to have a look at them. Be prepared to pay more than the first number you get told:bored:

Turbomeca help
 

Hi VF,
I am not going to hide behind the bush. I am a Turbomeca employee and would like to accomplish a number of things here:
a) first of all, congratulations for having 2 Arriel 2D having reached TBO already... that is pretty remarkable as a handful only have flown that much yet,
b) provide general info about difference between "creep limit" and "cycle life limit" as I think it might benefit all who have interest in this thread,
c) comment about the O/H cost difference question in general terms,
d) offer you to PM me if you want to contact me outside of the forum as an "official" Turbomeca person.

So for the creep counter, this "new" limit applied to the latest generation of Arriel 2 engines is only applicable to HP blades. It is essentially a continuous computation by the FADEC that takes into account the combined levels of rotational speed (N1 speed) and temperature (T45) the blades are subject to. The existence of this "new" live monitoring for HP blades has enabled Turbomeca to open some areas (think power rating capabilities) of the flight domain during certification. It is a tad different than the existing "Life Limit" defined in cycles (and mostly driven by variation of load based on rotational speed only... think of a cycle as one occurence of you loading the component by accelerating it from no load at all when engine is shutdown to some load as you accelerate it to say flight gate speeds... then you have partial cycles added when you lower the load and reinstall it before complete shutdown for whatever operational need that caused to significantly drop the collective and pull it back up later...) that has long existed on most engines for setting limit after which parts (mainly disks and similar rotating components + blades) have to be retired from service just like the creep. For info the Arriel 2D HP blades have both limits... creep and life in cycles as depending on how one operates, one or the other might be reached first. These 2 limits are aiming at controlling the risk of occurrence of 2 different components damaging modes.

For the O/H difference between the 2 engines the main reason why people must be gun shy to give you an estimate is mainly because there is very limited experience with return of 2D reaching O/H.
Now my 2cts is that if one engine has reached creep 250% while the other is only at 50% after roughly the same number of hours (4000hrs), that is probably because one has seen higher levels of N1 / T45 during its first TBO. I would venture to say that the cost of the O/H of the engine having seen the higher level of load may become higher if more heat related damage (cracking of NGV's or burner can) is found during inspection. The main difference though would be the set of HP blades IF the blades of the engine with only 50% creep are not rejected for other type of damage (like having lost the coating protection and starting to show signs of profile erosion for instance). Anyway, as you see there are lots of "if if if" in this and it is not to try not to answer you... It really is hard to completely predict prior disassembling the engine.

I hope this will help a bit. Please feel free to PM me if you wish to connect with me as an official Turbomeca person.

Safe and enjoyable flying to all

TurboLD


Thanks for your intervention in this thread, I enjoyed reading the technical details of your explanation.

G'day TurboLD

Thank You so much for the informative info. Will chat by PM re specifics :ok:

Happy Happy :O

VF

Great post Turbo LD.:ok:

Good post Turbo.

Refreshing to get some insightful, and useful info from the OEM. Turbomeca is a great engine, all be it sometimes on the expensive side. A tech rep that gives available considerations/options is always appreciated.:ok:

Thank you all - Technology goes fast in our industry - It is very very normal to have questions... Thanks for honestly putting them out there so that we can try to answer it.
Safe & Fun flying to all! :ok:

VF,
Not sure you PM'd me yet... If you did I cannot seem to see it yet... There might be a period of time when I am "being watched" as a new forum member.
If that were to be the case please simply get in touch with the Turbomeca Field Rep in your region, show him the post, and ask for similar level of info next time you have a question. He will have internal Turbomeca resources he can tap into if he does not have the information handy.
Best :)