Arriel Engine - Engine Life after 30 Sec OEI used
Thread Starter
Arriel Engine - Engine Life after 30 Sec OEI used
Ladies and Gents,
I have been told 2 different versions of the impact of using the 30 secs and 2 Minute OEI power settings on an Arriel 2 engine and wonder if someone has the definitive answer.
Option 1 - once the 30 secs of OEI power has been used, the high temperatures will have irrevocably damaged the turbine blades and the engine should be removed and refurbished - use of the 2 minute power is more flexible, with a maximum cumulative use of 10 mins before refurb.
Option 2 - the 30 secs power can be used up to a maximum of 10 times before compulsory refurb and the 2 minute power has a cumulative maximum of 20 minutes. The reuse of the 30 sec power is not limited to one flight and all 10 sessions can be used in one flight if required.
It may be that there are other options such simply borescoping the engines to inspect for damage and refurbing or not on condition.
Any thoughts?
I have been told 2 different versions of the impact of using the 30 secs and 2 Minute OEI power settings on an Arriel 2 engine and wonder if someone has the definitive answer.
Option 1 - once the 30 secs of OEI power has been used, the high temperatures will have irrevocably damaged the turbine blades and the engine should be removed and refurbished - use of the 2 minute power is more flexible, with a maximum cumulative use of 10 mins before refurb.
Option 2 - the 30 secs power can be used up to a maximum of 10 times before compulsory refurb and the 2 minute power has a cumulative maximum of 20 minutes. The reuse of the 30 sec power is not limited to one flight and all 10 sessions can be used in one flight if required.
It may be that there are other options such simply borescoping the engines to inspect for damage and refurbing or not on condition.
Any thoughts?
Option 2 is closer to the actual philosophy and cert requirements.
FADEC or Hydro engine?
FADEC engine will normally tell you that you have exceeded your cumulative limits - but will normally have one shot left in the bag so that you can use it to carry out a landing.
Borescope for damage? I doubt it.
Don't forget that along with the high temp you have possibly bounced up against the MAX Ng stop which is probably more likely in an Arriel.
Exact results may vary.
FADEC engines have higher limits as the control is more precise.
Caveat 2p only.
FADEC or Hydro engine?
FADEC engine will normally tell you that you have exceeded your cumulative limits - but will normally have one shot left in the bag so that you can use it to carry out a landing.
Borescope for damage? I doubt it.
Don't forget that along with the high temp you have possibly bounced up against the MAX Ng stop which is probably more likely in an Arriel.
Exact results may vary.
FADEC engines have higher limits as the control is more precise.
Caveat 2p only.
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From a philosophy point of view, you should have at least three 30 second OEI events in the larder, so to speak, before you take off.
One for an engine failure during takeoff, after TDP. where you are committed to going. Next one for a screwed up approach where you have to go around, (i.e. prior to LDP) and a final one to use when you are past LDP and committed to landing.
The maintenance manual should be able to tell you how many instances / how much time you have before the engine comes out.
One for an engine failure during takeoff, after TDP. where you are committed to going. Next one for a screwed up approach where you have to go around, (i.e. prior to LDP) and a final one to use when you are past LDP and committed to landing.
The maintenance manual should be able to tell you how many instances / how much time you have before the engine comes out.
Depends on the variant. The 2S1/2C1 needs a hot end change after any 30" power use, the 2S2/2C2 has provision for cumulative use. Both allow 10 min cumulative use of 2 min power. That's how it was when I operated them 10 years ago, but I doubt it's changed.
Thread Starter
It's the 2C with single channel DECU. Sorry, should have included that in the original post.
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The cumulative use of the OEI/LOW-2 min” is 10 min, with several incursions, for a maximum of 2 min per flight.
OEI LOW red LED will flash in the NG indicator when these 2 minutes are reached, and has to be reset before next flight.
The cumulative use of the OEI/HI-30” is 30”, with several incursions, or not, depending of the engine standard and MOD applied – See below.
From Turbomeca Engine maintenance Manual (Nov 2013):
- When cumulative use of OEI - Low reach 10 min : Removal and Overhaul of module 3, module 4 and DECU.
- BEFORE TU 6 or TU 14 : When OEI – Hi has been used : Removal and Overhaul of module 3, module 4 and DECU.
- AFTER TU6 or TU14 : When OEI – Hi has been used : Removal and Overhaul of DECU.
- AFTER TU6 or TU14 : When cumulative use of OEI – Hi reach 30 sec : Removal and Overhaul of module 3, module 4 and DECU.
- TU 6 : New material for free turbine envelope.
- TU 14 : Increase of the free turbine casing envelope.
From certification regulation, the 30 sec rating must be demonstrated 3 times on the same engines/same flight, but the RFM won’t mention it as being the limitation pilots could cope with….Just nice to know….
https://www.faa.gov/regulations_poli...cumentID/74478
Similar reg should exists in EASA regs, but no time to go through CS-Engine.
OEI HI and LOW cumulative use can be checked in the F.A.U display (Mode Memory – Digit G and J. To be checked in your RFM – Section 8.4 as there are plenty of different software version).
OEI LOW red LED will flash in the NG indicator when these 2 minutes are reached, and has to be reset before next flight.
The cumulative use of the OEI/HI-30” is 30”, with several incursions, or not, depending of the engine standard and MOD applied – See below.
From Turbomeca Engine maintenance Manual (Nov 2013):
- When cumulative use of OEI - Low reach 10 min : Removal and Overhaul of module 3, module 4 and DECU.
- BEFORE TU 6 or TU 14 : When OEI – Hi has been used : Removal and Overhaul of module 3, module 4 and DECU.
- AFTER TU6 or TU14 : When OEI – Hi has been used : Removal and Overhaul of DECU.
- AFTER TU6 or TU14 : When cumulative use of OEI – Hi reach 30 sec : Removal and Overhaul of module 3, module 4 and DECU.
- TU 6 : New material for free turbine envelope.
- TU 14 : Increase of the free turbine casing envelope.
From certification regulation, the 30 sec rating must be demonstrated 3 times on the same engines/same flight, but the RFM won’t mention it as being the limitation pilots could cope with….Just nice to know….
https://www.faa.gov/regulations_poli...cumentID/74478
Similar reg should exists in EASA regs, but no time to go through CS-Engine.
OEI HI and LOW cumulative use can be checked in the F.A.U display (Mode Memory – Digit G and J. To be checked in your RFM – Section 8.4 as there are plenty of different software version).
Thread Starter
gnz - thanks for that, it seems that option 1 is the closest and the 30 secs limit is absolute and requires rectification/removal/replacement. I will check to see what modification state our engines are at.
Yes, the FAU stores a lot of information, I'm just realising how much and how useful some of it is.
Woolf - on my aircraft it is far more likely to get an overtorque than an overtemp but you never know
I'll keep trying to avoid both!
Thanks to all the senior and regular commentators, I knew the pprune knowledge base would have the answers
Yes, the FAU stores a lot of information, I'm just realising how much and how useful some of it is.
Woolf - on my aircraft it is far more likely to get an overtorque than an overtemp but you never know
I'll keep trying to avoid both!Thanks to all the senior and regular commentators, I knew the pprune knowledge base would have the answers
