German Crews

My crews on my Ju-288 have gone back to Default level i had this problem last year wit American planes , have you any idea how i can sort this out please

don’t equip your aircraft to new crew slot, equip them onto a crew slot you maxed out

Thing is, it did not.
Simply put your aircraft in the slot you used it previously.

Easiest way to check on which slot you used your vehicle is to:
click on crew slot > select change vehicle.
You will see the list of the vehicle, if there is an exclamation mark, it means that you most probably using wrong slot - go to the next one and check.

Ju-288 has been spaded for a very long time ,

So put it in the correct crew slot with the upgraded crew