APPROXIMATELY 8 MIN AFTER TAKEOFF THE ACFT WAS OBSERVED AT A VERY LOW ALTITUDE. IT STARTED A RIGHT TURN THAT GRADUALLY STEEPENED UNTIL THE WINGS WERE ALMOST VERTICAL. AFTER ALMOST TWO TURNS THE WINGS LEVELED FOR AN INSTANT, THEN THE RIGHT WING & NOSE DROPPED & THE ACFT DOVE INTO THE TREES. THE PLT HAD A HISTORY OF A CORONARY ARTERY DISEASE BEGINNING WITH A CORONARY COLLAPSE IN 1962. HE WAS HOSPITALIZED IN 1971 & THE LAST EKG TAKEN PRIOR TO DISCHARGE SHOWED AN UNEQUIVICAL ACUTE HIGH LATERAL INFARCTION. HE WAS ADVISED OF THE HAZARDS & DANGER TO HIS LIFE IF HE SHOULD FLY IN AN AIRPLANE AGAIN.DURING THE FLT PHYSICALS OF 1977, 1979 & 1981 THE PLT MARKED "NO" TO THE MEDICAL RECORD HISTORY QUESTION CONCERNING ANY PREVIOUS HEART TROUBLES. THERE IS NO EVIDENCE THAT THE PLT EVER DISCONTINUED HIS PILOTING ACTIVITIES FOR ANY EXTENDED PERIOD DURING THE PAST 20 YEARS.