…. Here are the topics that are not related to technical issues.

checklist for the purchase of an airplane
.. Things you should check before buying an airplane / engine.

wear limits for a major overhaul and repair
When must a part be replaced during repair or overhaul?

...what should I specify if I have a problem and ask for help in a forum
So that you don't always have to ask when someone needs help.

the FlyDat from Rotax…
… the Rotax Flydat is often a mystery. Here is an attempt at clarification (error codes).

Downloads of technical documents
… what I found somewhere about engine-specific problems.

core hole diameter for metric ISO thread DIN 13
… always popular when repairing or making something.