20120401003999A

Pilot and sky divers took off from the Winterset, Iowa, airport at approximately 1500L time. Aircraft was flying a predominately north heading and on the climb out, pilot noticed that the cylinder head temperature was starting to climb abnormally. Although the CHT did not exceed manufacturer's limits, it was climbing higher than it normally indicated. At approximately 2500 feet above ground level, there was a loud bang and sudden severe vibration. White smoke came from out of the engine cowling over the top of the aircraft. The pilot leveled off, then pitched the aircraft for best glide speed, and turned back toward the airport. He advised the sky divers to exit the aircraft,as they had sufficient altitude. Four jumpers were able to exit and two remained with the aircraft. He initially selected a north-south highway to land on, but determined it was not suitable. He then selected a field and set up an emergency landing for the field. Upon landing, the nose gear broke and separated from the aircraft. The aircraft continued for a short distance and came to rest nose down in the field. All occupants were able to exit the aircraft without injury. There was no post crash fire.