Not just the Luftwaffe.
Army and Navy do as well, and so do I.
With 3 checkrides (for the Navy Sea Kings), you have to renew them every year.
Required is the IF Check plus a "standards check". We in the SAR world additionally do a "status check".
Bust your stand check and your license is gone.
Conversion to a civilian ATPL (H, IFR) license is a different matter.
More than 1000 hours in a multi crew, multi engine: Air Law exam and your done.
Less than 1000: Air Law, Power and Performance and Flight Planning gets you that ATPL.
Our big advantage obviously is that we hold an IF rating.
Thomas