Q: I bought my first plane, a 1981 Cessna T182RG, in May 2012. I have been flying this plane frequently and have put over 300 hours on it in the last calendar year. I can tell you that in 2005 it received a factory remanufactured engine from Lycoming and at the 1,000 hour mark got a complete top end overhaul. Now Lycoming shows the TBO at 2,000 hours, but I have found documentation from Lycoming that put the TBO at 2,200 hours providing you are running at 40 hours a month. For me that translates to the more you run the engine the more hours you can squeeze out of it.
How do they quantify that number? Is that based on history of engines running those hours having less mechanical issues at higher hours? Does that simply translate to 2,200 hours TBO for my engine?
How does the top end overhaul effect my TBO?
I can tell you that the compression is 4-6 pounds higher per cylinder now than when I did a pre-buy on the plane a year ago. It hadn’t run much in the few years previous to purchase so I am thinking blow-by was the culprit. I ran it wide open everywhere I went for the first six months and there were some pretty good oil stains on the belly from the exhaust, along with higher than expected oil consumption. The compression is now in the mid to high 70s and barely any exhaust streaks and low oil consumption. Not sure if that was a good idea but the results seem to indicate it helped.
I love the plane and the engine has been rock solid.
A: Donnie, I’m certain many others have had this question in the back of their minds at some point.
Your particular engine, the O-540-L3C5D in the Cessna T182RG, does in fact have a TBO (Time Between Overhaul Periods) of 2,000 hours. Even with the 1,000 hour complete top end overhaul, the TBO time remains at 2,000 hours…sorry.
The Lycoming documentation you discovered where it mentioned a 2,200 hour TBO is found in Lycoming Service Instruction 1009AV dated July 8, 2013. This Service Instruction lists TBO times for all models of engines, but does contain Notes that are very important. These Notes vary from model to model, and should be read carefully to determine if they apply to your specific engine model and how it may affect that model’s TBO time.
The O-540-L3C5D engine model has two Notes that apply, the first of which simply tells you that this engine was designed to incorporate exhaust turbocharging. The second speaks specifically about TBO times. The requirement for obtaining the 2,200 hour TBO time for this engine clearly states “if an engine is being used in ‘frequent’ type service and accumulates 40 hours or more per month, and has been so operated consistently since being placed in service, add 200 hours to the TBO time.”
From the information you provided, I don’t think you have met that criteria, but I’m certain you can understand the reasoning behind Note 11 in the Service Instruction. The secret to adding the 200 hours to the TBO time comes from the “frequent” operation and must be accomplished as mentioned in the publication from the beginning of the engine’s service life.
The worst thing you can do to any aircraft engine is to expose it to long periods of inactivity. This becomes a breeding ground for serious internal corrosion, which will contribute to a shorter service life. Some of the results of internal corrosion come in the form of camshaft and tappet spalling, and increased oil consumption from corrosion on the cylinder walls, which accelerates ring wear.
There is no substitute to flying the aircraft as frequently as possible, but not everyone can do 40 hours or more per month. However, those who can receive the reward of adding 200 hours to their TBO time.
Regarding your operation of the aircraft following its purchase, it sounds to me like you did a good job of saving the engine from a shorter life because of its past inactivity. This is not always the end result, so Donnie, I compliment you on your success here.