THE CREW WAS POSITIONING THE AIRCRAFT IN PREPARATION FOR A REVENUE FLIGHT AND EXECUTING A NON-DIRECTIONAL BEACON (NDB) APCH TO RWY 05. THE CAPTAIN REPORTED THAT THE COPILOT WAS FLYING THE ACFT. HOWEVER, THE CAPT STATED THAT HE TOOK CONTROLOF THE ACFT DURING THE APCH AND MADE SOME CONTROL CORRECTIONS BEFORE RETURNING CONTROL OF THE ACFT TO THE COPILOT. RADARDATA INDICATED THAT ACFT CONTROL WAS ERRATIC THROUGHOUT THE APCH AND THAT THE AIRSPEED AND DESCENT RATES WERE HIGH (3000 FPM SINK RATE) SHORTLY BEFORE THE ACCIDENT. THE ACFT STRUCK A FENCE SHORT OF THE RWY AND IMPACTED THE GROUND. THE CAPT SAID HE REALIZED THE ACFT WAS DRIFTING LEFT OF COURSE BUT DID NOT CORRECT IT. HE SAID HE TOLD THE COPILOT TO ADD POWER TWICE DURING THE APCH. THE COPILOT'S TRAINING HISTORY INDICATED DIFFICULTY IN CONTROL, SCAN OF INSTRUMENTS, AND WITH INSTRUMENT PROCEDURES. COMPANY MANAGEMENT DESCRIBED THE CAPT AS PASSIVE AND THE COPILOT AS AGGRESSIVE. SUPERVISION OF TNG AND OPERATIONS BY MANAGEMENT AND SURVEILLANCE OF THE COMPANY BY THE FAA WAS CONSIDERED INADEQUATE BY NTSB.