. ▁None ▁of ▁these ▁hel ic op ters ▁are ▁based ▁at ▁De elen ▁however ▁and ▁for ▁that ▁reason ▁the ▁base ▁is ▁only ▁fully ▁oper ational ▁when ▁exer cis es ▁take ▁place . ▁The ▁closure ▁of ▁So ester berg ▁Air ▁Base ▁resulted ▁in ▁a ▁lot ▁more ▁hel ic opter ▁movements ▁at ▁Gil ze - R ij en ▁Air ▁Base , ▁and ▁in ▁order ▁to ▁reduce ▁traffic ▁there ▁it ▁was ▁decided ▁to ▁use ▁De elen ▁more ▁often ▁as ▁a ▁training ▁site . ▁To ▁facil itate ▁this ▁it ▁was ▁decided ▁to ▁res ur face ▁part ▁of ▁the ▁run way ▁and ▁to ▁create ▁a ▁slope ▁for ▁hel ic op ters ▁to ▁practice ▁s loped ▁land ings ▁on . ▁The ▁increased ▁importance ▁of ▁De elen ▁resulted ▁in ▁it ▁once ▁again ▁receiving ▁the ▁design ation ▁of ▁Air ▁Base ▁( D utch : ▁V lie g bas is ). ▁ ▁There ▁is ▁also ▁gl ider ▁activity ▁on ▁the ▁field ▁and ▁very ▁nearby ▁there ▁is ▁a ▁second ▁aer od rome ▁used ▁almost ▁exclus ively ▁by ▁gl iders , ▁Ter let ▁Air field . ▁ ▁References ▁ ▁External ▁links ▁Dutch ▁Ministry ▁of ▁Def ense , ▁Milit air ▁L ucht va art ▁Ter re in ▁De elen ▁( D utch ▁only ) ▁ ▁Air lin ers . net ▁- ▁Ph otos ▁made ▁at ▁De elen ▁ ▁Category : Ro yal ▁Netherlands ▁Air ▁Force ▁bases ▁Category : A ir ports ▁in ▁Gel der land ▁Category : R ij ks mon uments ▁in ▁Arn hem ▁Category : R ij ks mon uments ▁in ▁E de