On November 27, 2000, at 1730 eastern standard time, a Piper PA-28R-180, N4914J, had its engine cowling separate from the airplane during takeoff climb from Merritt Island Airport, Merritt Island, Florida. The airplane was operated by the commercial pilot under the provisions of Title 14 CFR Part 91 and visual flight rules. Visual meteorological conditions prevailed and no flight plan was filed for the local flight. The pilot was not injured and the airplane sustained substantial damage. The flight was originating from Merritt Island, Florida, at the time of the accident. According to the pilot, this was his second flight of the day. He taxied to runway 29 and departed to the west. He said he noted nothing out of the ordinary on takeoff or climb out until reaching about 500 feet when the engine cowling separated from the airplane. From where he sat he believed the front left side separated first, shook violently then rolled toward the right rear side. The cowling broke off a piece of the right windscreen, spun off and hit the baggage door and finally collided with the stabilator. The pilot stated that he made a gentle left turn to downwind and landed the airplane safely on runway 29. He recalled seeing nothing to indicate a loose cowling during his preflight inspection. Examination of the engine cowling found impact damage around the nose/intake area, and was also cracked just forward of the oil access door. The forward reinforced composite structure had separated from the cowling and was broken into four pieces. This structure contained the cowl alignment pins, and there was no abnormal wear observed between the cowl pins, or the pin receptacles located on the lower cowling. Examination of the upper cowling revealed that three of the four fastener assembly studs were missing. The remaining stud was located on the left, rear fastener assembly, and was held in place by a retainer ring. Closer examination of the left-rear cowl latch fastener assembly revealed during the operational test that the stud positively engaged the receptacle when turned 1/4 turn clockwise. Some looseness remained between the fastener and the associated receptacle. The tip of the stud had a polished appearance, but did not appear to be excessively worn. Review of the airplane maintenance logs revealed that the brake hydraulic system was serviced on November 17, 2000, about 7 flight hours before the mishap.