Old wives tales...
Ernie,
I'm curious where you've obtained your 1500 hour statistical criteria, that failure rates start becoming frequent within and beyond this time frame.
I look at it this way: If the engine has performed well within the last hour, it's most likely to perform in the same mode during the next hour. Trend monitoring of the engines, how they sound, what they look like under the cowl at Cessna maintenance recommended checks (like the exhaust system), as well as the look of the oil and burn rate would seem to be better indicators of what to anticipate as far as overhauling an engine. In fact, in may be a situation that the power producing end may be the only items that need to be taken care of, i.e., the cylinder assemblies.
With the new turmoil on the VAR cranks, those that have a good running engine should think twice about splitting cases.
I see no statistical probabilities or mortality rates for an engine that is 10 years old versus one that is 20 years old or older.
Nice graph, but I don't think it's very realistic.
As to Rickyskymaster's question, my thought is run them until there is a problem... but do the preventive maintenance as recommended in the Cessna service manual. As long as compressions, oil usage and all other parameters are within acceptable ranges... if it ain't broke don't screw with it.
SkyKing
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