ON RADAR VECTOR ASSUMED CLEARED FOR APCH WHEN PUT ON INTERCEPT HEADING. GOT BELOW MINIMUM VR ALT.

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WHILE BEING RADAR VECTORED FOR AN NDB APCH TO RWY 22 AT SCHENECTADY ARPT; NY; AT APPROX 10 NM (ACTUAL DISTANCE COULD NOT BE DETERMINED) WE WERE GIVEN A VECTOR TO INTERCEPT FINAL COURSE INBND. (THE CTLR'S EXACT WORDING LED BOTH PLTS TO BELIEVE WE WERE CLRED FOR THE APCH. UNFORTUNATELY NEITHER PLT CAN REMEMBER THE EXACT CLRNC) ONCE ESTABLISHED. ON FINAL WE BEGAN OUR DSCNT TO MDA OF 940' (CATCH). JUST PRIOR TO DSCNT WE ENCOUNTERED VMC CONDITIONS. AT APPROX 1500' APCH CTL ADVISED US TO MAINTAIN 2300'; THAT WE WERE 12 NM FROM ARPT. WE IMMEDIATELY BEGAN A CLB TO 2300'. BOTH PLTS WERE UNDER THE IMPRESSION THAT WE WERE CLRED FOR THE APCH. A GOOD CALL BY THE CTLR PREVENTED A POSSIBLE ACCIDENT. LESSON LEARNED: LISTEN FOR AND USE PROPER TERMINOLOGY. ALSO; IF IN DOUBT; ASK FOR DISTANCE (REMEMBER TWA/DULLES ARPT; WASHINGTON). IN ADDITION: APCH CHARTS FOR NDB/OR VOR W/O DME SHOULD HAVE XING RADIALS TO HELP DETERMINE REMAIN WITHIN DISTANCES--ESPECIALLY WHEN BEING VECTORED FOR FINAL IN LIEU OF FLYING THE ENTIRE APCH! WX AT SCH WAS 800' CEILINGS. CEILINGS TO N WERE RAGGED UP TO 2300-2400' MSL.