On August 7, 2016, at 1123 Atlantic standard time, a Diamond DA20-C1, N828BB, was destroyed during collision with terrain following a bounced landing and runway excursion at Henry E. Rohlson International Airport (STX), Christiansted, St. Croix, US Virgin Islands. The student pilot and flight instructor were seriously injured. Visual meteorological conditions prevailed, and no flight plan was filed for the local instructional flight, which originated at STX about 1030, and was conducted under the provisions of 14 Code of Federal Regulations Part 91.In a telephone interview, the student pilot stated she could not recall the details of the accident flight due to her injuries. In a written statement, the flight instructor stated that the student completed a "normal" traffic pattern, but "bounced" the landing. The flight instructor took the flight controls, initiated a go-around and retracted the wing flaps. He described a shallow turn back to runway heading and establishing a 60-knot climb before he, perceived a "severe decrease" in engine power and a loss of lift. He extended the wing flaps to the takeoff position, and the airplane impacted the ground. According to a statement from an STX air traffic controller, the airplane had completed one touch-and-go landing and was cleared for a second touch-and-go landing. Just prior to touchdown, the airplane "tilted" to its left, and the left wingtip appeared to strike the ground prior to the main landing gear. The airplane continued, and bounced four to five times before it banked "hard" to its left, departed the landing surface, and crashed into trees north of the runway. A witness near the airport heard the accident occur, but he did not see it. He said he heard the sound of an airplane engine at low rpm as it approached the airport. He said the sound was consistent with a small airplane on final approach. He said the engine then accelerated to a "high rpm condition" for 3 to 5 seconds before the sounds of impact were heard. According to Federal Aviation Administration (FAA) records, the flight instructor held a commercial pilot certificate with ratings for airplane single-engine land, multiengine land and instrument airplane. He held a flight instructor certificate for airplane single engine. He was issued an FAA second-class medical certificate on January 29, 2016. According to the operator, the pilot had accrued 506 total hours of flight experience. The student pilot was issued an FAA third-class medical certificate on June 10, 2014. According to the operator, the student pilot had accrued 34.6 total hours of flight experience. The airplane's most recent annual inspection was completed June 24, 2016, at 1,982.9 total aircraft hours. The airplane came to rest approximately 1,700 ft beyond the approach end of runway 10, and 410 ft left of the runway centerline. Examination of the airplane by FAA aviation safety inspectors revealed the tail section and the engine compartment separated from the cockpit and cabin structure. The engine remained attached by wires and cables. Control continuity was established from the cockpit to the flight control surfaces through cable breaks and cuts made by recovery personnel. Examination of photographs revealed angular cuts in tree branches where the airplane entered the trees adjacent to the runway and above the crash site. At 1053, the weather reported at STX included few clouds at 1,800 ft and wind from 120° at 10 knots. The temperature was 32° C, dew point was 26° C, and the altimeter setting was 30.05 inches of mercury. The engine was examined at the manufacturer's facility under the supervision of the NTSB. The engine was rotated by hand at the propeller flange, and continuity was confirmed from the powertrain through the valvetrain to the accessory section. The force required to rotate the crankshaft was greater than nominal, and the source of the resistance could not be immediately determined through external visual examination, and internal borescope examination. The engine was disassembled, and impact damage to the front of the engine resulted in the No. 4 engine bearing and oil "slinger" to impinge upon the crankshaft, preventing smooth rotation. Examination of the internal components and bearings revealed normal wear and lubrication signatures and no preimpact mechanical anomalies. Bench testing revealed the magnetos and the fuel injection system were fully functional and that there were no anomalies that would have prevented normal operation. According to FAA Advisory Circular AC-61-23C, Pilot's Handbook of Aeronautical Knowledge: "The effect of torque increases in direct proportion to engine power, airspeed, and airplane attitude. If the power setting is high, the airspeed slow, and the angle of attack high, the effect of torque is greater. During takeoffs and climbs, when the effect of torque is most pronounced, the pilot must apply sufficient right rudder pressure to counteract the left-turning tendency and maintain a straight takeoff path."