Benton, LA, USA
N202AT
Air Tractor AT-802A
The agricultural airplane was returning from its first spray load of the day when it impacted trees and a swampy canal while on final approach to land. The pilot radioed to the ground crew that he was inbound for landing and was not heard from again. The airplane impacted trees located on the east side of the canal and the wreckage was found on the west side of the canal. The flap actuator was found in the 10-degree extension setting. Post-accident examination of the wreckage did not reveal any anomalies with the airframe, engine, or propeller that would have affected the aircraft's performance. Toxicology tests detected 0.037 ug/ml of diphenhydramine in the pilot's blood and an unquantified amount of diphenhydramine in his urine. Diphenhydramine (commonly known by the trade name Benadryl) is an over-the-counter antihistamine used in symptomatic management of allergic symptoms and also for its sedative, antitussive and antispasmodic effects. The American College of Physicians-American Society of Internal Medicine conducted a study (Effects of Fexofenadine, Diphenhydramine, and Alcohol on Driving Performance) on the effects of diphenhydramine on driving performance. The results of that study indicated that "Participants had significantly better coherence after taking alcohol or fexofenadine (Allegra) than after taking diphenhydramine...After participants took diphenhydramine, driving performance was poorest, indicating that diphenhydramine had a greater impact on driving than alcohol did."
HISTORY OF FLIGHT On November 14, 2001, at 0930 central standard time, an Air Tractor AT-802A agricultural airplane, N202AT, was destroyed when it impacted trees while on final approach to land near Benton, Louisiana. The airplane was registered to and operated by Aeronautical Technologies Inc., of Clovis, New Mexico. The commercial pilot, sole occupant of the airplane, sustained fatal injuries. Visual meteorological conditions prevailed and a flight plan was not filed for the 14 Code of Federal Regulations Part 137 aerial application flight. The local flight originated from the LJ Earnest Airport, Benton, Louisiana, at 0910. According to another pilot who was spraying the same fields as the accident airplane, they waited for fog to lift in the morning and began their spraying. He stated that they dispersed their initial load and were returning to the airstrip to reload. The pilot added that when he was on short final he heard the pilot of N202AT report that he was eight miles out and inbound for landing. The pilot reloaded and flew back to the spraying area and after a little while, noticed that N202AT had not returned to the spray area. He inquired to the ground crew if they had seen N202AT. The ground crew reported that they had not seen nor heard from N202AT since his last radio call inbound. The other pilot began to search for N202AT and found the aircraft in a swampy area 300 yards from the approach end of the airstrip. PERSONNEL INFORMATION The non-instrument rated commercial pilot held an airplane single-engine land rating with the following limitation, "Carrying passengers in airplanes for hire is prohibited at night and on cross-country flights of more than 50 nautical miles." The pilot was issued a second class medical certificate on February 28, 2001, with a limitation dictating that he "must have available glasses for near vision." According to the last FAA medical application, the pilot reported having accumulated 11,332 hours of total flight time. According to acquaintances of the pilot, approximately half of his flight hours were accumulated in turbo propeller aircraft. AIRCRAFT INFORMATION The 1996-model agricultural airplane was painted yellow with blue and black stripes along its sides. The airplane was outfitted with an 800-gallon hopper tank. The airplane was equipped with a Pratt & Whitney PT6A-67AG turbo propeller engine and a 5-bladed constant speed, reversing, and feathering Hartzell propeller. Review of the aircraft's maintenance records revealed that the records were "lost when returning from a job in Pennsylvania." The airplane had been owned by Aeronautical Technologies Inc., since new, and the company attempted to duplicate the records from work orders. A Satloc Global Positioning System (GPS) was installed in October 1996. On August 20, 1999, at an engine total time of 1,802.2 hours and 577 total cycles since new, the engine was removed "due to FOD (foreign object damage)." The engine was sent to an overhaul facility for repair and a hot section inspection, and was reinstalled on the accident airplane on October 6, 1999. A maintenance entry dated December 28, 2000, indicated that the propeller was removed for overhaul and was reinstalled. On May 2, 2001, the propeller was dynamically balanced. On July 19, 2001, during a "100-hour inspection" at an aircraft total time of 3,666.0 hours, the elevator, rudder, and horizontal stabilizer were removed and replaced, and the elevator trim cables and the rudder trim push-pull rod ends were replaced. On July 28, 2001, the aircraft underwent its last annual inspection at an aircraft total time of 3,666.0 hours. On the same day as the annual inspection, the engine underwent a 100-hour inspection at an engine total time of 3,038.1 hours and 1,149 total cycles since new. METEOROLOGICAL INFORMATION At 0856, the weather observation facility at the Shreveport Regional Airport (located approximately 16 miles southwest of the accident site) reported the wind from 120 degrees at 8 knots, visibility 4 statute miles in mist, broken clouds at 25,000 feet, temperature 16 degrees Celsius, dew point 14 degrees Celsius, and an altimeter setting of 30.20 inches of mercury. WRECKAGE AND IMPACT INFORMATION According to FAA inspectors, who responded to the accident site, the airplane impacted trees and water approximately 300 yards east of the airstrip. Review of photographs taken at the accident site revealed that the main wreckage came to rest on the west side of a swampy canal. There was a swath of freshly broken trees approximately 50 feet wide that descended approximately 10 degrees toward the water on the eastern side of the canal. On the eastern side of the canal, the right main landing gear wheel was found in the water. The aircraft was fractured into multiple sections. The cockpit remained intact; however, its instrument panel was separated. The area in front of the cockpit, which included the hopper and engine, was separated from the airframe; however, the hopper and engine remained attached to each other. The propeller was separated from the engine; the aft section of the reduction gear box remained with the engine, and the forward section of the reduction gear box remained attached to the propeller. The wing structure was separated into three main sections; a fragmented right outboard, the left outboard, and the center section. The empennage was separated from the fuselage just aft of the cockpit. The vertical and horizontal stabilizers were separated from the empennage. Photographs of the wreckage at the accident site revealed that the power, propeller, and condition lever console was partially separated from its mount and all of the controls were found in the mid-range position. Photographs of the flap actuator at the accident site revealed that 6 threads were visible, which correlates to a 10-degree flap extension setting. According to the FAA inspectors who responded to the accident site, a rainbow sheen (similar to that caused by petroleum products) was noted over the surface of the water. They reported that fuel could be smelled throughout the swamp. The FAA inspectors removed the high pressure fuel filter and noted fuel in the bowl. The aircraft wreckage was transported to Air Salvage of Dallas, Lancaster, Texas, for further examination. MEDICAL AND PATHOLOGICAL INFORMATION The medical examiner reported that he found the seat belt and shoulder harnesses unbuckled and undamaged when he arrived on scene. Photographs taken from the accident site show the seatbelt and shoulder harnesses unsecured. The medical examiner asked the first responders if anyone had undone the seatbelts and they responded in the negative. A white helmet was found hanging from a tree branch by its communication cord. It is not known whether the pilot was wearing the helmet at the time of the accident. An autopsy conducted by Forensic Pathologists, Inc., of Bossier City, Louisiana, determined that the cause of death was traumatic injury. Toxicological testing was conducted on the pilot by the Civil Aeromedical Institute, Oklahoma City, Oklahoma. The toxicology results revealed that 0.037 ug/ml of diphenhydramine was detected in the pilot's blood, and an unquantified amount of diphenhydramine was detected in his urine. Diphenhydramine (commonly known by the trade name Benadryl) is an over-the-counter antihistamine used in symptomatic management of allergic symptoms and also for its sedative, antitussive and antispasmodic effects. The American College of Physicians-American Society of Internal Medicine conducted a study (Effects of Fexofenadine, Diphenhydramine, and Alcohol on Driving Performance) on the effects of diphenhydramine on driving performance. The results of that study indicated that "Participants had significantly better coherence after taking alcohol or fexofenadine (Allegra) than after taking diphenhydramine...After participants took diphenhydramine, driving performance was poorest, indicating that diphenhydramine had a greater impact on driving than alcohol did." TESTS AND RESEARCH According to the operator, they had the GPS card removed and examined to see if any non-volatile memory concerning the flight could be downloaded. The operator reported that the spray runs were present, but the return flight to the airstrip was not. On January 24, 2002, the NTSB investigator-in-charge along with representatives from the airframe, engine, and propeller manufacturers, examined the wreckage. The airframe wreckage was laid out so that the flight controls and their trim systems could be examined. The establishment of flight control continuity was not possible due to the extent of the damage; however, all control and trim separation points were examined and all displayed fracture surfaces consistent with overload failure. The engine remained attached to the forward fuselage and was intact. The two exhaust stacks displayed impact damage and the propeller reduction gear box was separated at its attaching flange. The exhaust manifold was removed and the compressor drive turbine was visible and displayed no anomalies. The compressor turbine was rotated manually and it, the compressor, and accessory section gears rotated freely and smoothly. None of the turbine or compressor blades displayed rotational damage nor was there any evidence of rotational scoring on the casing. The power turbine was examined and displayed no damage. The power turbine would not rotate; however, its output shaft was rusted to the reduction gear box's second stage ring gear. The gears were rusted; however, they did not display any unusual wear marks. The fuel control unit (FCU) was examined along with the engine accessory section. The power lever was found in the 65% power area and the P3 override was in the off position. The FCU was removed from the engine for further examination. The propeller remained attached to the forward end of the reduction gear box (first stage) and all five blades remained attached to the propeller hub. The governor remained attached to the forward section of the reduction gear box; however, its pilot valve was torn from the governor. The beta valve was in place and remained attached to its beta block assembly; however, the block assembly was separated from its collar. The propeller blades were labeled 1 through 5 for identification purposes. Blade #1 displayed no rotational scarring, little to no bending, was found in a reverse pitch setting, and its pitch change link remained attached at the blade butt clamp and the propeller piston. Blade #2 was bent aft and rotated 180 degrees and its leading edge was facing the opposite direction of rotation. Its pitch change link remained attached to the blade butt clamp; however, it was fractured from the propeller piston. Blade #3 was bent almost 90 degrees opposite the direction of rotation and twisted toward a low pitch setting, and its pitch change link remained attached to both the blade butt clamp and the piston, even though it was bent. Blade #4 displayed leading edge gouging at its tip and was twisted toward a low pitch setting and bent in the opposite direction of rotation. Its pitch change link remained attached to the blade butt clamp; however, its piston connecting bolt was sheared. Blade #5 was found with its butt rotated to the feather position and the tip of the blade twisted toward low pitch. Its pitch change link remained attached at the butt clamp and piston ends. The propeller spinner sustained impact damage and was punctured from the inside out near some of the blade counter weight areas. Disassembly of the propeller revealed that the piston was found approximately 2 inches below the feather stop. The propeller's four feather stop screws were in place and secured to the spring retainer cup. The propeller blades were removed and their bases were examined. Two of the blades left witness marks on the blade hub supports that equated to -13.8 and -16.8 degree angles. The maximum reverse pitch angle is -10 degrees +0.5 degrees. As mentioned previously, some of the blades were twisted toward the low or reverse pitch setting, and it is unknown as to what the exact blade angle was at the time the airplane impacted the trees. Examination of the instrument console revealed that the beta caution light was destroyed and its filament was missing. The Woodward 8063-037 FCU (serial number 11520838) was sent to an FAA inspector for testing at the manufacturer's facility on February 13, 2002. According to the FAA inspector, the FCU was bench tested and no anomalies were noted. ADDITIONAL INFORMATION The wreckage was released to the owner's representative on February 19, 2002.
in-flight collision with trees while on final approach to land for an undetermined reason.
Source: NTSB Aviation Accident Database
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