Understanding Engines Part 3 – High Time Engines

Recap of What we Have Learned

Before we talk about high time engines, lets recap our last two posts.   We discussed time between overhauls (TBO), since major overhaul (SMOH), and since top overhaul (STOH).  You now know that engine manufactures establish a recommended time between overhauls and that this time is usually engine running hours and/or calendar time.  For example 2000 hours flight time or 12 years calendar time whichever comes first.   You also know that engines can run well past the established recommended times, but many engines never come close to these times before needing an overhaul.   How often an aircraft flies and regular engine maintenance indicates how long an engine will last before an overhaul.

You also learned that there is really no such thing as a top overhaul, that it means different things to different people and when an aircraft classified states that the engine has received a top, you really have to dig deep to find out what has actual been done to the engine.

Putting it all into Perspective – High Time Engines

This brings up a question that is often asked by buyers, should you buy an aircraft with a high time engine?

First what is a high time engine?

Again this term is defined differently by people.  Some view a high time engine as being well past TBO; while others think it is any engine with over 1000 hours.  Our rule of thumb at 3Point is that it is any engine within 400 hours of TBO.

Would we buy an aircraft with a high time engine?  Absolutely yes and have on a couple of different occasions.

As long as it is the right aircraft for the mission, is well looked after, serviced and flown regularly we would. Engines can and often do run well past TBO.  If there is every indication that it will run well, given a proper inspection we would.  The two main factors when considering a high time engine is 1) It has been flown often, and 2) has the oil been changed regularly.   It has to be flown regularly, not just ground run.   Engines have to reach normal running temperatures to stay healthy and this is not usually accomplished on the ground.

What about Price?

Now with all this being said, we also expect a big discount on the price if we are buying an aircraft with a high time engine. The aircraft also has to be a good one, for example low airframe hours, great instruments and/or avionics, good paint/fabric etc.   We consider all these items in any decision when helping our clients, and we do a quick calculation of how many more hours we believe our client can get on the engine before overall.   This all factors into the maximum price we have our client negotiate.  Remember that engine overhauls can be very expensive at 20K plus depending on engine.

What about Reselling?

Another item to consider when buying an aircraft with a high time engine is that reselling will be a challenge. Most potential buyers will shy away from a higher time engine. Price always sells, and that’s why it is so important that you do not overpay when you complete the initial purchase.
There can be some additional advantages to buying an aircraft with a higher time engine. For example you may find a great aircraft that would be perfect with an engine upgrade. You could purchase, fly it for a time and instead of doing an overhaul replace the engine with an upgrade.  An upgrade usually means a more powerful engine. Once again make sure the price is right and factor in how much the upgrade will cost you.

With all things considered, an aircraft with a higher time engine may be right for you.  As long as you understand the purchasing process and do not overpay you will have hours of enjoyment.

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