jeppsbore
I do the 50hr check exactly as per Socata maintenance manual. Every item is ticked off.
I know some people disagree but think of this:
a) the FAA oversees about 10x more GA planes than the rest of the known universe, and there is no evidence of problems they have which the CAA fleet doesn't, and
b) The manufacturer is better placed to decide what should be done, rather than some generalised CAA checklist which will, at best, be generalised.
One can argue with this but it soon resembles the argument that all convicted child molesters should be executed upon conviction, on the grounds that one cannot take any risk.
Statistically, the % of incidents attributable to lack of maintenance is very low. The % of incidents attributable to defective maintenance is also very low, but these numbers are probably comparable in the order of magnitude. I know this sounds cynical but if you take your G-reg in for an Annual after every 10hrs airborne time, you are probably increasing your chances of it plummeting compared to it seeing the JAR145 firm only once a year - simply because the chance of somebody messing it up is greater.
Not to mention the very obvious fact (obvious to any owner who started off with something new) that most damage to an aircraft is done during maintenance. Screws chewed up, threads damaged, cowlings cracked, bits of composites chipped off, windows scratched, etc. Apart from stone chips on the prop, every piece of damage I see was done during maintenance.
There is no problem doing a short run with cowlings off. I have an EDM700 which monitors CHTs and EGTs for all 6 pots. No point in removing top cowling only; most leaks will be on the bottom. Lyco's recommendations are all based on a near total lack of engine instrumentation, which is quite reasonable.