On December 2, 2001, at 1121 Pacific standard time, a Bellanca 8KCAB, N50554, was destroyed during an uncontrolled descent into the Pacific Ocean near Long Beach, California. The certified flight instructor (CFI) received serious injuries and the commercial pilot under instruction (PUI) received minor injuries. Hart Air was operating the airplane, registered to a private individual, under the provisions of 14 CFR Part 91. Visual meteorological conditions prevailed for the instructional flight and a company flight plan had been filed. The local flight originated from Long Beach about 1035. According to the CFI who was in the rear seat, he was observing the commercial pilot in the front seat as part of a 30-day recurrency checkout. At 4,500 feet msl, the flight instructor demonstrated a 4-point roll and then asked the PUI to conduct one. The CFI transferred control to the PUI and shortly thereafter, the nose dropped 20-30 degrees below the horizon. The PUI asked the CFI if he was doing that intentionally, to which the CFI replied no. The CFI then pulled the control stick aft to no avail. He told the PUI to try the trim, but it would not budge. The CFI then told the PUI to bail out twice. The PUI jettisoned the door and bailed out. The CFI struggled over the seat before reaching the door. He pulled himself out and pulled his parachute ripcord just prior to impacting the water. The CFI estimated that the time between the loss of airplane control and impact with the water was 30-45 seconds. An eyewitness, located approximately 3 miles from the accident site, reported seeing several single engine airplanes conducting flight maneuvers offshore. All of the airplanes were flying above what the witness estimated to be 4,000 feet above ground level (agl). His attention was drawn to one of the airplanes, which had descended to approximately 2,000 feet agl. According to the witness, the airplane was making steep turns, climbs, and descents, and he believed the airplane was "too low for those types of maneuvers." The witness observed a parachute open in the sky adjacent to the airplane, while the airplane continued to fly in the aforementioned manner. Once the airplane reached approximately 500 feet, the airplane dove "nearly straight down towards the ocean." The witness then observed the airplane pull up within 6 feet of the ocean surface. The airplane "climbed nearly vertical to approximately 300 feet, rolled over into a dive and impacted the water at a high rate of speed." The airplane accumulated a total of 1,786 hours, and underwent its last annual inspection 40 hours prior to the accident. The airplane was not recovered.