THE COPLT BGN TAKEOFF (TKOF) WITH 2700 RPM & 52 TO 53.5' OF MANIFOLD PRESSURE (MP). WTR INJECTION WAS NOT USED ALTHO 12 GAL WAS AVAILABLE. AT 150 TO 250 FT AGL, THE L ENG LOST PWR & THE L PROP AUTOFEATHERED. THE CAPT TOOK CONTROL (CTL) & TOOK ACTION TO VERIFY L ENG FEATHERING. NEITHER PLT MOVED ANY OF THE OTHER ENG CTLS. A TURN WAS INITIATED TO RETURN TO THE ARPT, BUT THE ACFT BGN LOSING SPEED & ALT. SUBSEQUENTLY, IT CRASH LNDD IN A PARTLY WOODED AREA SHORT OF AN OPEN FLD & BURNED UNTIL FIRE FIGHTING PSNL ARRIVED. THE IMPELLER WAS DEMOLISHED BY FIRE, BUT EVIDENCE OF DEBRIS FROM THE IMPELLERWAS FND IN THE L ENG INTAKE & ON TOP OF ITS #3 & # 11 PISTON. THE COMPANY'S STATED POLICY WAS TO USE WTR (WET TKOF), EXCEPT WHEN PRECLUDED BY MECHANICAL MALFUNCTION OR LACK OF ADI FLUID; HOWEVER, 4 DISSIMILAR POWER CHARTS WERE FND IN THEACFT. TKOFF WT WAS 38,670 LBS. PERF MANUAL SHOWED ACFT CAPABLE OF 420 FPM CLB WITH 12 DEG OF FLAPS, 1 PROP FEATHERED, LNDG GEAR UP, DRY PWR (NO WTR). MAX PWR SETTING WAS 2700 RPM & 56' MP FOR DRY TKOF; 2800 RPM & 59.5' MP FOR WET TKOF.