On January 7, 1997, about 0603 eastern standard time, an Ayres S2RHG-T65, N3100U, registered to the United States Department of State, International Narcotics and Law Enforcement Affairs, operating as a public-use airplane was on a drug eradication mission when it collided with trees near San Jose del Guaviare, Columbia. Visual meteorological conditions prevailed at the time and a company flight plan was filed. The aircraft was destroyed, and the United States licensed commercial pilot was fatally injured. The mission was to involve two flights of two aircraft. For tactical purposes the accident airplane was designated T-4, and the other airplane in the flight was T-3. The flight took off at 0548, and proceeded to the assigned area of operation, located about 18 nautical miles northwest of the village of Calamar. According to the pilot of T-3, about 0635 he attempted to contact the pilot of T-4 on the VHF radio to no avail. After numerous attempts, at 0640, he asked the crew of the flight's escort helicopter to attempt to make radio contact. The helicopter crew was not successful, and at 0645, the helicopter's crew began to search for the missing airplane. About 0715, with no sign of the airplane, or any smoke or fire, the Operations Center at San Jose del Guaviare was notified of the missing airplane. At 0725, full-scale search and rescue activities were begun utilizing both Colombian and United States assets. According to the Operations Center's radio log, the wreckage was found by a search helicopter, at 1435. The navigation equipment data card aboard the airplane was removed and the information from the data card revealed that the airplane had descended and leveled off at 630 feet mean sea level (msl. The airplane had reached that altitude at 0603:15, and was at a speed of 202 miles per hour (mph). At 0603:16, the data revealed that the aerial application began. The application pattern continued, with the position data placing the flight over the two fields prior to the tree line where the accident occurred. At 0603:22, the airplane was at an altitude of 633 feet msl, and at a speed of 198 mph, when the data card indicated that the aerial application ceased. The next three data points (at a 2 second sampling rate) showed that the airplane had descended to 617 feet msl and was at a speed of 197 mph. The last plot from the airplane was recorded at 0603:28. According to the FAA inspector's report, the accident site revealed that "the initial known accident impact was with a tall, straight hardwood tree in excess of 100 feet in height and about 8 inches in diameter at the height where it was struck." Two sections of the tree, 32 feet and 5 feet in length, were broken off of the remaining trunk. The 32 foot section was found on the ground near the base of the tree, and the 5 foot section had been carried over into the main impact area. The impact area consisted of moderate to dense jungle, with no man made structures affected by the accident. The elevation at the crash was estimated to be about 400 to 500 feet msl. The tree line observation was about 600 feet msl. According to the FAA's report, "...during the on-scene examination of the aircraft wreckage, none of the investigative team members noted any evidence of the aircraft having been struck by any type of weapons fire." The engine was shipped to Pratt & Whitney's facilities at Longueull, Quebec, and torn down under the supervision of the Transport of Canada, Aircraft Certification Branch, on April 18, 1997. According to the Transport of Canada's report, "evidence suggest[s] that the engine was running at time of impact and likely producing considerable power." For details of the engine teardown see the Transport of Canada report enclosed with this report. The propeller was shipped to Hartzell Propeller's facilities at Piqua, Ohio, and torn down under the supervision of the FAA, on March 27, 1997. The four blades had separated from the hub, and all the blades displayed impact damage. No fatigue fractures were noted on any of the fracture surfaces, and no discrepancies were found.