N-star,/norwy,,there is no reason why you should not train NVG letdowns without radar.In military operations,radar is not used,as it is a big `flag`,so you use the other aids you have.And above all else you should do a lot of pre-planning,using a map,for land or sea,otherwise reliance on databases in FMSs can lead you astray,as evidenced by the loss of the ICG S-92,an aircraft that has a fairly complete suite of navigation and advanced FCS,including radar...However,if you do not do the appropriate training and currency........?
You may not be aware .but military crews do not have `licences`,nor AOCs,etc,etc...they may ,of course hold such licences in a private capacity,but not under Military Rules....