NYC84FA073

An FBO mechanic reported that the plt had requested a jumpstart. The wx was cold (20 deg) & the initial attempted eng start was unsuccessful. After being preheated, both engs were started. Nothing abnormal was noted during taxi, run-up & the takeoff roll. However, during the initial climb, black smoke was observed trailing from the left eng. At aprx 600 ftagl, the smoke stopped & the acft entered a shallow left turn & started to loose alt. The plt declared an emergency & said he 'lost' his left eng. Sublsequently, the acft was observed to roll, enter an uncontrolled descent & crash. Witnesses heard the sound of eng power, but could not tell whether it was from 1 or 2 engs. No preimpact, mechanical failure was found. There was evidence that the gear was extended, the flaps were up & both props were at a low pitch (unfeathered) setting. The left prop blades had little rotational damage. A test of the plt's blood showed: cocaine 0.25 mg/l, benzoylecgonine 3.78 mg/l, morphine 0.32 mg/l, codeine 0.07 mg/l & CO2 9.2 to 18%. The plt was a hvy smoker.