Sunday, May 18, 2008

Maintenance on Your Own Plane

Figuring out what to do on maintenance on your new plane can be a hard task in the beginning. At first it feels like you pick a mechanic who you do not know much and you have to trust him and then he hands you multi-thousand dollar invoices.

The First Years

The first year of maintenance is always hard; even if you have a fairly well kept plane. Most of the time a plane is sold because the owner has lost interest in flying. So he has also lost interest in upkeep. So he may do the minimal amount, but you are likely to want a little better when you get the plane. Prepurchase is very key here; try to find all the items you can before the sale and negotiate getting them fixed.

The other item that can make the first year expensive is just having a new mechanic looking at the plane. He will likely find things the previous mechanic did not. In some ways I like having different people look at my plane on occasion. Either the shop has two IAs or swap between shops. Being loyal and having somebody experienced with your plane is good. But having new eyes look at it are good too.

My first couple years were expensive. The engine had been doing great, but at the first annual, a cylinder needed to be rebuilt. Later the exhaust system was found to be needing a replacement. The muffler was known to be close at the prepurchase, but the exhaust system was not. These things add up.

Maintenance Management Class

One thing I would highly recommend to most plane owners is to take the Savvy Aviator Class by Mike Busch. It is not a class to teach you how to repair your plane, but to know enough that you can get your maintenance done at the right price.

The FAA named Mike as its "National Aviation Maintenance Technician of the Year" for 2008. He is a knowledgeable A&P/IA and nice guy. After taking the class he has also been agreeable to answer questions I have had. Very nice!

Engine TBO

One of the things Mike Busch is advocate of is watching your engine carefully and overhauling on the condition of it. If the engine is at TBO, but working well, do not overhaul. Part of the idea with this is that many new engines have failures in the first 100-200 hours. This can be due to bolts not getting tightened properly, etc.

If you are doing oil analysis, using an oil filter (and inspecting it), and preferably using a multipoint engine analyzer, your engine should give you plenty of warning of problems according to Mike Busch and others.

Oil Filter

If you don't have an oil filter, check into getting a conversion kit. It lengthens the time you can use the oil. On some engines, it can be the difference between a 1500TBO and 2000TBO. If it is not stated, it is still a real plus. Less metal stays in the oil. Also, if there is metal, it gets trapped better and you can see it when the mechanic cuts the filter for inspection. This can be key to catching any possible engine problems. If you are nearing TBO, it is even more important and the oil filter conversion can be transferred to the new engine at some point.

I got the F & M Enterprises oil filter adapter for my Continental O470. It attaches directly to the engine without oil lines. The oil lines can be a concerning point of failure. There are no recurring AD inspections on it; some do. With practice and a ziplock bag around the filter, the filter can be removed quite easily and without mess during an oil change.

Oil Analysis

The oil analysis programs I have used is Aviation Laboratories and Blackstone Laboratories. I liked some of the on-line reporting that Aviation Labs did, but I like the more personal service that Blackstone Labs does. In the end, I have kept with Blackstone Labs. One thing that is important is to try to keep consistent with the lab; what you are watching for is not an immediate good/bad answer, but a trend of multiple analyses that indicate something good/bad.

Multipoint Engine Analyzers

Multipoint engine analyzers are great! I initially thought it was for getting accurate leaning and maybe trying lean of peak. This is an important one, but I end up using my fuel flow meter to lean to (after determining the corresponding leaning with the analyzer). But what I value more is seeing EGTs and CHTs simultaneously looking good while in IFR or flying over the moutains.

I have actually seen one EGT bar indicate a problem before i could hear anything. I switched to a single mag and it was better. I cleaned the plug when on the ground (and I knew exactly which plug to check from the analyzer) and the problem was solved. Exhaust valve problems can sometimes be seen by uneven erratic levels. All this gives me a lot more confidence in the engine and this is important with only one engine.

Keeping the Cylinder Head Temperature below 400F is very important from what I hear. 390F is probably better. I feel the analyzer really helps with that. It checks all cylinders, not just one. Also, I have an alarm light that lights up if it is over my predetermined number.

I have the Electronic Instruments UBG-16. It has extra boxes which takes more time to install. It is a very good instrument. I might have gone with the JPI EDM-700 now if doing it again, but they are pretty much equal.

Get a Written Estimate

At least get a verbal estimate, but preferably get a written estimate. If you do not let the mechanic know what price numbers will upset you, you will likely get upset. The mechanic will probably have some idea going into it what the costs will be. Better to know up front than be surprised later. It may go a little over, but make arrangements with the mechanic to call you if this happens before it goes way over.

This is another big thing that Mike Busch advocates and I think it has helped me. It puts all parties on the same page.

Ask Questions

Most mechanics are very agreeable to questions. You learn more about the repair and understand the price and you learn more about your plane. A lot of finding strange problems can involve the pilot trying to diagnose in the air or in the conditions you see them.

Help out with the annual if you can. People call it the owner-assisted annual. You can often at least pull all the inspection plates. Watch him do the compression check and oil change. It may save you some money. Even if it does not save you anything, you will understand more about your plane.


  • Take Mike Busch's class if you can. They are offered all around the country.
  • Do oil analysis.
  • Get a written estimate.
  • Ask questions.


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