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The point is there is a level of inspection and an action that must be taken. Simply cleaning and running isn't the terminating action. Even IAW the part of the c20 manual you posted. An additional inspection is required. IE removing and reinspecting the plugs. Note that it says to remove and inspect the plugs after the 30 minute run. It does not say remove and inspect plugs only if the light illuminates.


Maybe "old wives tale" isn't the best description, however the main gist here is that the applicable M&M will give you the required procedures to follow and the level of inspection and/or follow up to take.


This 30 minutes ground run somehow migrated from the C20 manuals to become the normal inspection for all. It just ain't so.


This, "To advise that this is strictly an old wives tale may cause pilots to doubt their engineers even when they ARE following the MM.", Is an excellent point and I retract the sentiment. Fingers faster than brain sometimes.


I stand by the rest though.




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c'mon I'm an a-star guy, and we all know they can give grief too...lets just all stop flying altogether now and get into trucking. Does Ice Road Truckers need a few more up and comers?

the be an install problem would dictate a tooling or training issue.   seeing the bearing continues to have issues, i would lean more to a design issue.

As mentioned the 407 engine has 3 problem areas:1- the torquemeter gear,2-the #2 bearing,3- the #4 bearing...all of these have been addressed with new parts...it should be mentined that the chip detec

the C20 is a different animal if you want to really make a comparison to the original topic being the powerplant of the 407.

Also, I think those statements in the manual haven't changed since I got out of college, so they're very dated like myself :blink: . Are they any different for the 407? Anyone? Beuller? Beuller??


the 407 engine is vastly different on the power output and should be treated with the respect that deserves. The known history of the bad bearing would make me learn as much as i could about it so I'm prepared to diagnose the problem early.


As for the C20, the size of the flakes and the 4 slivers allowed is tiny when you think about it. so it does not take much to take the engine out of service as per the manual when you do have a problem. I'd be curious to know if the majority of wrenches measure the chips or just eyeball them on for size. And I find it interesting there isn't a qty limit for chips. basically how it's worded i could have a cristmas tree of 0.5 diam chips and still be in service.

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RTR, Not sure what you mean by “Lastly the quoted post is patently wrong.”

I’m referring to section 71-02-07-280-801/802 of the Arriel 1D1 maintenance manual that clearly states that metal particles found in the oil system are to be sent to a Turbomeca approved laboratory for analysis in order to determine if the engine must be removed for further investigation or if it can remain in service. The closest approved lab is Jet Care in New Jersey.

That means that when your Astar is out in the bush and the pilot finds metal on an engine chip plug, regardless of how tiny and pissant the find might be, that A/C is not moving until the metal is analyzed by Jet Care, and your Turbomeca tech rep tells you what your next course of action must be.

You want to take a guess how long it takes to get a sample from a bush camp in northern Alberta to New Jersey and how much money that down time costs?

Last time it happened we had to remove the engine because of suspected high speed bearing material. The engine shop inspected the engine and found nothing wrong with it and then handed us an invoice for $47000.00.

Add to that the cost of the rental engine, shipping, hiring a picker truck, lost revenue, angry customer, etc. Having the option to check the plugs after a 30 min ground run would be a luxury.

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