To verify/document that the engine has not passed the hours is easy, it doesn’t involve any work or anything, just a signature in a log book, and it lasts for 2000 operation hours or thereabout. Airworthiness of an engine based on “condition” requires continuous work to assess this condition
That’s a false dichotomy. An engine that a bureaucratic overlord insists must get overhauled at 2000 hours still must have all the condition inspections, having a verifiable TBO doesn’t make the condition inspections go away (at least not for any owner who doesn’t want an unexpected engine stoppage). Just because it’s not reached 2000 hours yet does not mean it is airworthy. Just because it has passed 2000 hours doesn’t mean it’s materially not airworthy. An engine gets signed off on condition whether it’s before TBO or not, it has to so you still must do all the condition assessment whether the engine has reached TBO or not. So it’s just an additional (and pointless) burden that some bureaucrat has imposed.
Your bureaucratic “has to be verifiable” thinking is what has gotten us into the sad situation where instead of safety, we have heaps of paper and instead of decision making by competent personnel, we have pencil pushers drawing terribly bad regulation.
That is true, I agree 100% – in principle. There is an alternative to this. The Air Forces has operated like that all the time. If there are less pencil pushers is another matter, but decision making is done by competent personnel and the actual “condition” of any and all equipment is always a known quantity . But the military has “infinite” resources compared to GA. How many persons are needed to keep only one single fighter in operational condition? 50? 100?
Yes, engines are run “on condition” here also. Most of them by the looks of it 
Taking a manual check now and then is not the same as condition based maintenance as I know it. It is not a replacement for a TBO. By installing measurement equipment, online databases etc. data analysis on a continuous basis – only then will you have a system that will tell you about the actual condition, a system that also is economically feasible.
LeSving, are you trolling this forum? You seem to like to state one thing and the opposite…
The Air Forces has operated like that all the time
Sure? I’ve read that the Sukhoi Su-27 Flanker’s AL-31F fans had a TBO of 50 hours. That put me off from buying one
(NB: the forum doesn’t seem to support the full unicode character set)
@ LeSving (and I guess anybody else who might be interested…), I mentioned the hazards of doing doing nutty things with simple planes and experimental VW power, or maybe just nutty things in general… For academic completeness here’s the 1979 Ken R accident report N4KR Read between the lines and it says he was VFR on top flying the Turbo-Revmaster VW powered KR from Texas to Los Angeles (Chino) non-stop, I think I remember reading he flew it to 17,000 ft max. When he got to California the engine failed (fuel exhaustion perhaps, who knows) and he descended through clouds into snow and 1/4 mile visibility, and into terrain. Wild times. Turbo KR
(I enjoy people who push limits much more than those who don’t… VW aero engines are a pretty good example in my experience, to a greater or lesser degree depending on the approach. The problem I’ve noticed is that those who really do push limits tend to end up dead… God bless them for showing us where the limits really are)
LeSving, are you trolling this forum? You seem to like to state one thing and the opposite…
No and no. Maybe I just write too clumsy, I don’t know.
VW aero engines are a pretty good example in my experience, to a greater or lesser degree depending on the approach
You have to remember several thousand VW are flying. Limbach has alone sold more than 6000, and who knows how many of the French VWs have been used and still are used (10,000 + maybe?) Not that an AeroVee is a Limbach, Sauer or a JPX, but the basic design is exactly the same. The main difference is these more optimized engines have a considerably lower RPM range (more torque at lower rpm) than the more “of the shelves” auto part conversions. VW engines have been completely squeezed out of the European market by Rotax, but 20-40 years ago they ruled.
