So all this engine talk has me thinking about what are the simple things I can do to be more pro-active in my engine maintenance.

Right now I do compressor washes when over in the islands, down in Florida.

I'm currently flying behind the pt6a-67p. I'm at 1900hrs with a recommended HSI of 2000hrs and then a TBO of 3500hrs. I'm currently in the 300-400 hrs per year range. Most of my trips are longer than 2hrs.

Other than the compressor washes, what else should I be doing. For my HSI inspection, where should I get this done?

Other than pushing the lever forward I'm a neophyte in this area. I would love to get feedback from the ag operators (Craig C) as well as those in the turbine engine biz.

When taking off I limit my ITT to less than 780 and keep my NG in cruise to book. My engine itself is making book numbers in cruise and seems generally happy.

Questions like how often should I borescope, clean the nozzles, (which has been done twice at annual), etc. etc.

I understand sulfidation, but don't know whether there is anything I can do to minimize it.

I would also like to get everyone's thoughts on trend monitoring.

This article says P&WC recommends nozzle cleaning ever 400 hours but they recommend 200 - 300 hour intervals - http://blog.covingtonaircraft.com/2015/04/16/the-basics-of-pt6-engine-maintenance/

Fuel nozzels should spray the fuel into the combustion chamber. When they get dirty the fuel will streak rather then spray and the fuel will act as a blow torch and damage the combustion chamber. This is often a problem found in the HSI.

This article describes the proper way nozzels should be cleaned - http://www.aviationpros.com/article/10381482/pt6-fuel-nozzles

Frequent checking of your nozzels will lessen the chances of a surprise at HSI.

I have used Dallas Airmotive in the past.

You have "Know your PT6A Turboprop" - http://www.caijets.com/pdf/KnowYourPT6A.pdf

You should post your questions in the Beech Turbines section where all of this has been discussed for the KAs.

Our #1 life extending concern on PT6A engines is to keep good batteries in great condition to ensure cool starts. We actually have automatic switches installed that change the start voltage from 24v to 48v during the course of the start. The engines will actually start cooler than they will idle using that technique.

You shouldn't have to deal with sulfidation on a 60 series engine. Most of those issues were on the small block engines that weren't run very hard.

As for fuel nozzles, how many hours do you average per year? We run somewhere between 450-700 hours and have had good luck doing nozzles twice per year. Once at annual and once when we estimate that we are half way through the season.

Since you have a nearly new airplane, I'd just follow the recommendations with the possible exception of shortening your fuel nozzle cleaning schedule.

In our case, we are running 10,000+ hour engines and have found that we save a ton of money by doing hots about every two years. That usually puts us around 1000 since the previous hot and nearly everything we find can be repaired very cheaply. The biggest thing is usually cracks in the combustion liner which can be welded up for $1000 or so instead of requiring an overhauled or serviceable part be substituted. Since we provide the hangar and do much of the labor of removing cowlings, etc., our hot section labor is usually only around $1500 or so.

I think a borescope every year would be a good idea, but since our hot section labor is so reasonable, I don't see the advantage in not splitting the engine. That said, I wouldn't split one at a factory authorized shop, or a FAA certified repair station ahead of schedule since they probably have some rule that every hot must end up costing $15,000 or more.

Its also a huge help to your mechanic and your pocket book to keep a good trend monitoring book so you can spot trends easily. One thing some trend monitoring books don't have a blank for is max Ng achieved prior to fuel introduction. If you will wait for the starter to max out the Ng prior to spraying and sparking, you can tell the health of the batteries and starter. When that number starts to drop off, find out why and fix it.

What gave you an HSI of 2000 hours? This chart says the 67P HSI is 1,750 and TBO is 3,500.

And HSI is not recommended, it is mandatory.

https://www.pt6a.aero/maintenance/pt6a-tbo-hsi-service-intervals/

Manual allows for 50 hours of overflight but even then that's only 1800.

What gave you an HSI of 2000 hours? This chart says the 67P HSI is 1,750 and TBO is 3,500.

And HSI is not recommended, it is mandatory.

https://www.pt6a.aero/maintenance/pt6a-tbo-hsi-service-intervals/

My maintenance facility. I will check with them today.
Roger on the mandatory.
Craig, I'm coming to your place

I've spoken to two different ag operators that I use frequently. They both echo Craig's experience with regard to HSI's. That is, they do them themselves every couple years. They tell me that a few thousand bucks in labor and worst case about 10 grand in parts is all they see. When we get to talking about the costs reported under part 91 ops and having the work performed at some mainstream turbine shop, their eyes almost fall out of their heads.

We are part 91 also. Legally, there is no difference in the maintenance required on an ag plane vs. any other part 91 turbine single.

I just started flying a PT6 powered airplane and in 100 hours I've learned a few things. First, I agree on cleaning fuel nozzles more frequently than 400 hours. Its not particularly expensive and the consequences of a bad nozzle are crazy money. Here's a photo of a CT vane that likely was damaged due to streaking from a bad nozzle.

If the defect in the vane is large enough the turbine wheel must be scrapped. That's like a $90K part so you want to avoid that. I also had an issue where my starter generator was cutting out maybe 2-3% early on Ng speed and it resulted in 40 deg hotter start than the other side. That is one indisputable advantage of a twin. When one engine starts to act up you can see it in comparison to the other. Anyway I learned that the SG is needed just as much after you introduce fuel as it is to get Ng up to speed for the start. If it cuts out even a couple % before its supposed to it results in a hotter start and my C425 guru said it was bad for the engine because that is right when the secondary injectors start adding fuel. The engine gets a boost of more fuel and it needs to easily accelerate, aided by the SG, up to idle RPM. If it bogs down that is apparently bad.

Besides fuel nozzles and compressor washes I think with a PT6 you need to jump on problems early before they get insanely expensive.

We caught a vane like that one year and it was still repairable. I'm pretty sure if we did hots on Pratts schedule, the vane would have scrapped and so would the CT blades. I think it cost a few grand to have it welded up and recoated.

As for the starter, yes, it needs to put out until the ITT gets over the hump and you establish your normal idle. Any weakness in the starter needs to be addressed asap as one bad start can trash the engine.

We are part 91 also. Legally, there is no difference in the maintenance required on an ag plane vs. any other part 91 turbine single.

That CT vane was from an airplane I was considering buying. I called Covington and showed them the photo and asked if it would last until the next HSI which was something like 500 hours. The Covington guy said he wouldn't fly it another 2 hours. So yeah, if you delay then the problem gets more expensive by a factor of 100 or so...

Confirmed for the 4th time tonight.

Part 91, 2000 hrs, part 135 is 1750 plus a 50 hr 'grace' period.

Craig, given what Scott is saying, how do we do a HSI inspection like you do?

Right now, given that an HSI for single one time private owner is of very little value to a 'HSI' shop to try and 'earn' your business.