replacement cooling system hoses

I don't know what rules apply in your country however your local automotive parts supplier should be able to assist you - I use, almost exclusively, Gates products as they provide extensive technical specifications for their hoses, that meet/exceed Rotax specifications.

"Intending to replace the cooling rubber tubes after 5 years of service, "

FYI; The 5 year rubber replacement is for ALL rubber, not just hoses/tubes

I use Gate's hose too. You.must use the 17mm hoses on top and the two 17mm hoses under the cylinders. The larger

25mm / 1 inch hose to the radiator from the expansion tank and the other one from the radiator to the coolant pump can be purchased locally. There is nothing special about these two 25mn / 1 inch coolant hose so long as they meet specs.

Thanks for the replys. In the meantime I found that the coolant large lines and the oil lines are supplied by Tecnam, the airplane manufacturer and appear in their IPC, and I'm awaiting their quote. The issue is more complex than just the tubes since some of them have formed metal crimp connections, so it's either getting the tube/hose with the connections or replacing both tubes and connections.

As to the 5 years replacement, yes we know and already replaced fuel lines, rubber gaskets, rubber flanges and carb parts and every other rubber parts. Thanks.