Flying an Army OH58 in the early '80s, we determined that we would not have the fuel to make our planned destination. Passing Kessler Air Force Base, we called the tower for landing instructions.
"Do you have PPR?" [PPR = "prior permission"]
OH58 (not knowing what "PPR" stood for) :
"No. [pause] All we have is a transponder and an ADF."
"Clear to land."