By Paul Wiley

This article describes an overview and some highlights after reading “Mike Busch on Engines” a book about piston engine design, operation, condition monitoring, maintenance and troubleshooting for General Aviation (GA) aircraft.  I heartly recommend that you purchase this book and read it cover to cover.  It is an excellent addition to any GA pilot’s library.  It costs about $30 on Amazon.  The book is a good mix of theory and practical tips on engine operation.  Busch regularly runs his engines safely, efficiently and well beyond TBO. 

Main Takeaways:

Here are some important takeaways I got from reading this book, presented in no particular order:

• ·Overhaul of GA piston engines (and propellers and accessories) should be based upon condition, not TBO hours or any arbitrary time (don’t euthanize your engine prematurely based soley on hours of operation)
• ·Every GA airplane owner should install a digital engine monitor that records CHT and EGT for each cylinder. Most modern digital engine monitors record CHT, EGT and other engine parameters, and this data can be downloaded and analyzed to determine engine health as well as provide an early warning of possible issues with the engine.
• ·Airplanes should be flown regularly and the oil changed about every 25 to 50 hours and 3 to 4 months
• ·At each oil change the oil filter and screen should be inspected for metal and the oil sent out to a lab for analysis. Regularly changing oil is one of the best forms of preventative maintenance.
• ·Busch prefers running Lean of Peak (LOP) when possible. This is contrary to what we were taught years ago and what some airplane manufacturers recommend in their pilot operating manuals.  Unfortunately, I don’t think we can run LOP in some GA airplanes without unacceptable engine roughness.  But check it out as Mike Busch makes some very persuasive arguments backed by a lot of data for LOP operation. I recommend a discussion with your mechanic as to the feasibility of LOP operation in your plane.
• ·Busch regularly does a “mag check” while operating LOP in cruise flight. Why check the mags at LOP?  At LOP any problems with the ignition system are more likely to show up because you have minimum fuel going to the cylinders needed for combustion at LOP, thus an ignition system problem is more likely to happen and will be easier to see.
• ·A key point Busch makes repeatedly is that performing maintenance is the mechanics job, but managing the maintenance is the owner’s job. Don’t cede airplane maintenance management to your shop.
• ·Busch lists five rules for good management of aircraft maintenance:

1. 1. Choose the right shop (or mechanic) – one that is competent, communicative, and cooperative
   2. Insist on a written estimate – get a written discrepancy list and estimate before approving work
   3. If it ain’t broke, don’t let ‘em fix it
   4. Don’t fix it until you’re sure what’s wrong (don’t “shotgun” parts hoping to fix a problem)
   5. Don’t overkill the problem by doing more than is necessary to fix the problem

• ·Your alternator is the primary electrical system; the battery is the secondary or back-up system. Always check voltage after start-up.  Most airplanes come from the factory with an ammeter, but no voltmeter.  Note that many engine analyzers have a voltmeter along with EGT, CHT and other indicators. 
• ·Ask your mechanic if he has a borescope and if he has used it to look at your engine, how does it look?
• ·Regarding required maintenance, the FAA proscribes “how to” and “when to” do this maintenance.

1. 1. For the “how to” the mechanic (or pilot if performing maintenance, the owner is allowed to do) is required by FAR 43.13 to use “methods, techniques and practices” specified in the current manufacturer’s maintenance manual or Instructions for Continued Airworthiness.
   2. For (operations under FAR part 91) the “when to” the mechanic (or pilot if performing maintenance the owner is allowed to do) is NEVER required by FAR to comply with a manufacturer’s guidance as to when an engine or accessory needs to be overhauled or replaced with 2 exceptions: 1) When an Airworthiness Directive (AD) requires overhaul or replacement at a specified interval, or 2) if it is set forth in an FAA approved Airworthiness Limitations Section of the manufacturer’s maintenance manual or Instructions for Continued Airworthiness. 

• ·Recommendations for detecting exhaust valve failures (and other potential engine problems) before they happen are:

1. 1. Regular borescope inspections
   2. Engine monitor analysis – see Busch’s book for more detailed instructions
   3. Oil analysis can provide early warning of potential problems. Being on a Spectrographic Oil Analysis Program – (SOAP) is recommended to identify trends in engine wear

• ·Engine Lubrication: Oil is usually just thought of as providing lubrication and reducing friction for the moving parts; but it actually does 6 key functions. Oil lubricates, cools, cleans, seals, actuates and preserves our engines.  Busch prefers monograde instead of semi-synthetic or synthetic oil. He likes Aeroshell W100.  I recommend a discussion with your mechanic concerning what type of oil to use. 
• ·Oil consumption: This is another subject that requires a lot of context as there are many factors affecting oil consumption. Generally speaking, anything from a quart in 20 hours to a quart in 4 hours is in the “normal” range.  Continental doesn’t consider oil consumption to be concerning until it exceeds a quart in 3 hours and says it is not an airworthiness issue until it exceeds about a quart per hour.  (wow !!!)
• ·Oil dipstick level: Busch recommends filling to about 2/3 of the maximum sump capacity, i.e., if your plane holds 8 quarts maximum, 6 quarts would be ideal.  Or in this example, not less than 5 quarts and not more than 7.  Any more than 7 quarts and the engine will vent it overboard. 
• ·Five “Golden Rules” for making the engine last a long time:

1. 1. Don’t let it rust – should not be a problem for us in the dry Arizona climate and especially if usually hangered. Corrosion is the number one reason engines don’t make it to TBO!
   2. Avoid cold or dry starts – especially important after a long period of disuse
   3. Keep the engine clean – this primarily means regular oil and oil filter changes
   4. Watch the temps – DO NOT exceed 400 degrees F for CHT (Lycoming says < 500 deg F)
   5. Minimize stress – This mainly means not “slamming” the throttle or prop controls, but rather using smooth and steady inputs, even when (for example) executing a go-around.

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