8 year discretionary hose replacement

[Mile high]

Is anyone familiar with Diamond stating that there is a discretionary hose replacement for a recommended 8 year replacement of fuel tank interconnect and vent lines and LH & RH 8 year coolant hose recommended replacement due.
My mechanic put it on the annual report and it’s quite expensive. He said he wasn’t sure the purpose and pointed out it was discretionary. Has anyone else performed this procedure or have feelings about it one way or another.

[Gordon]

Here in Australia, I was told all the 8 year items including engine and tank hoses were mandatory. We had them all done last year at the 8 year point.
For the tank hoses, the wings have to come off, the metal tanks are then pulled out of the wing and large diameter interconnect hoses replaced. Of course I was worried that after the work their would be problems, leaks? fuel guage problems? etc as I was of the feeling "if it ain't broke don't fix it".

As we know DAI started as a glider company back in the day and gliders have their wings off all the time. Turns out removing a wing on a DA62 is a one hour job (the actual hose replacement takes longer). It all went back together fine and we have had zero problems in the year since.

Engine hoses. FYI, not all hoses are automatically supplied/replaced when an engine is replaced. We ended up changing all hoses as it was "mandatory" here. We had a small delay for a couple of the hoses - DAI should know exactly how many are needed as they know when each plane hits 8 years! If you are going to do it just make sure all the hoses are available before you put your plane in the shop.

As mentioned, we haven't had any subsequent problems and although I was reluctant at the time, I'm kind of glad to have new hoses throughout the fuel system and engines now.

[nickname]

If a shop hasn't pulled wings before it can be quite some labor. For Diamond shops it's routine for major structural inspections or replacing fuel probes.