Let's Get Technical
September 1, 2020
As Technical Advisor, Mark Manning brings with him over 38 years of aviation experience. He has performed maintenance on over 35 different types of aircraft and has flown more than 25 different models of aircraft.
Q: I’m looking at buying a used airplane. Are there any items you typically look for in a pre-buy inspection that I can use to narrow down the list of aircraft I send an A&P to inspect? Bill K.
A: It all depends on the type of aircraft and age but I’ll try to cover the basics. I look at the logs to determine how many hours it has been flown per year up to current date. I think total time isn’t as important as the currency of time flown such as once or twice a month or more.
Another consideration is the corrosion inside the engine. I usually take the plugs out and do a borescope inspection of the cylinders and look for pitting of the cylinder walls. Also check the fuel filters for debris or soft rubber chunks because if stored a long period with auto gas (with any amount of alcohol) it can deteriorate the inside of rubber hoses.
The engine is where you can spend the most amount of money to bring back to airworthiness if corrosion has developed from sitting too long or in a high humidity climate.
I also check all control cables for signs of rust and general condition.
If it’s a fabric covered airplane, where was it stored, (hanger or ramp) and when was the covering last replaced and was the process followed per the covering manual.
Some older cover jobs the STC’S were only up to the silver and you could use your choosing of topcoat which sometimes caused problems with paint cracking ect. The current STC’S require the use of their products in all stages to the final finish so you can’t legally use other paint for color as in the earlier STC’s, this seemed to limit the cracking of the topcoat for many years.
Everything else is just a general look over and if available a nice conversation with the previous owner on how much the airplane was flown and for how long such as an hour flight or just 10 min in the pattern.
You’ll get a better prebuy if the A&P has worked on and is familiar with the type of airplane being looked at.
Hope this helps and remember to keep the fan turning, it keeps the pilot cool.
If you are in the process of building or restoring your own aircraft you can now send in a question to be answered in a future issue of the Minnesota Flyer by Technical Advisor Mark Manning.
Please send questions to: