Do you know if the AAV can be repaired ?

In what sense? It's got several components to it that probably have varying degrees of difficulty to repair, but sure, it can be repaired. Is the basic problem that it is sticking -- not opening or closing? You can try soaking it in PB Blaster (or something else) for a day or two. You can also carefully pry open the body of it to clean it from the inside. I did that once, and it was not too difficult.

I am assuming we are talking D-Jet AAV (or AAR). There's a good write up here about halfway down the page: https://members.rennlist.com/pbanders/DJetParts.htm

yes we do them all of the time, and install modern guts

The problem is the solenoid that never become hot.
Thank you Beatnavy, George for your answers.

also we have many many customers in Belgium, because my wife Mia is from Menen Belgium

Yes i know Georges. I am a customer of yours and i already wrote to Mia for orders. Hurrah for Belgians !

AAV=Amphibious Assault Vehicle?