Corning, IA, USA
N802LL
AIR TRACTOR INC AT-802A
The flight was established in an extended climb on a west-northwest course toward the intended destination as it approached a line of thunderstorms. Radar data depicted the airplane passing through 12,000 feet mean sea level (msl) and continuing to 16,000 feet msl over a 9-minute period. After reaching 16,000 feet, the flight altered course several times, apparently in an attempt to clear the line of thunderstorms. The maximum altitude return was 17,700 feet msl during the flight. About 1-1/2 minutes before the accident, the flight reversed to an easterly course and descended from 17,400 feet msl to 15,200 feet msl. The airplane momentarily climbed to 16,300 feet msl during that time. About 50 seconds prior to the accident, the airplane entered a descent from 13,400 feet msl on a steady southeast course. The descent continued until impact. The airplane impacted an open field. It was fragmented during the impact sequence. Sections of all flight control surfaces were observed at the accident site. No malfunctions consistent with a preimpact failure were observed during the postaccident examination. The radar data indicated that the pilot operated the unpressurized airplane above 12,000 feet msl for approximately 24 minutes, and above 15,000 feet msl for at least 14 minutes of that time. Federal Aviation Administration publications note that at cabin altitudes between 12,000 and 15,000 feet "judgment, memory, alertness, coordination and ability to make calculations are impaired." They also stated that "pilot performance can seriously deteriorate within 15 minutes at 15,000 feet."
HISTORY OF FLIGHT On August 15, 2009, at 1116 central daylight time, an Air Tractor AT-802A, N802LL, piloted by a commercial pilot, was destroyed during an in-flight collision with terrain near Corning, Iowa. The cross-country flight was being conducted under 14 Code of Federal Regulations (CFR) Part 91 without a flight plan. Visual meteorological conditions prevailed in the vicinity of the accident site. The pilot sustained fatal injuries. The flight reportedly departed Rantoul National Aviation Center Airport (TIP), Rantoul, Illinois, about 0930. The intended destination was O’Neill Municipal Airport (ONL), O'Neill, Nebraska. The flight’s ultimate destination was Napoleon, North Dakota, with an intermediate stop at ONL to refuel. The airplane was reported overdue by the operator about 2030 the day of the accident after the airplane and pilot could not be located. Initial attempts to locate the flight were unsuccessful. An Alert Notice (ALNOT) was issued at 2136. Local authorities were notified of a possible downed aircraft at 0001 on August 16th. Sheriff’s Department and State Patrol efforts to find the airplane during the night were unsuccessful. The airplane was located at 0726 the following morning after a daylight aerial search. Radar data indicated that the flight was established on a west-northwest course and in a gradual climb as it proceeded across south-central Iowa. About 1044, the flight was at 11,200 feet mean sea level (msl), approximately 8 miles south of Chariton, Iowa. At 1053, the flight was located about 5 miles south of Osceola, Iowa; climbing through 12,500 feet msl. The airplane continued the extended climb, reaching 16,000 feet msl about 1105. It was located approximately 3 miles south of Creston, Iowa, at that time. Shortly thereafter, the airplane turned to a northwest course until 1108 when it turned left about 90 degrees to become established on a southwest course. About 1111, the airplane turned right to become established on a westerly course. According to the altitude data, the flight was passing through 17,000 feet msl about that time. About 1114, the flight reversed course; ultimately becoming established on a southeasterly course prior to impact. About that time, the airplane began to descend. Altitude data indicated that at 1114 the airplane was at 17,400 feet msl and beginning the turn to reverse course. About 1115, the flight had completed a 180-degree turn and had descended to about 15,200 feet msl. Over the next 14 seconds, the airplane gained about 1,000 feet before beginning a final descent. Altitude data indicated that at 1115:23 (HHMM:SS) the airplane was about 16,300 feet msl. At 1115:46, the airplane’s altitude was about 13,400 feet msl. And at 1116:00, the altitude was about 11,500 feet msl. The final radar data point was recorded at 1116:27, with an associated altitude of 3,800 feet msl. The final data point was located approximately 0.16 miles northwest of the accident site. The airplane impacted an open field about 8 miles east of Corning. The debris path was oriented on an easterly course and was approximately 585 feet long. The airplane was fragmented during the impact sequence. The elevation of the accident site was approximately 1,265 feet as provided by a handheld global positioning system (GPS) receiver. PERSONNEL INFORMATION The pilot, age 60, held a commercial pilot certificate with single and multi-engine land airplane ratings, and a helicopter rating. He was issued a second class airman medical certificate without limitations on April 20, 2009. On the application for that medical certificate, the pilot reported a total flight time of 29,200 hours, with 600 hours flown within the past 6 months. The pilot’s logbook was recovered from the wreckage. The most recent entry was dated April 1, 2009, and noted a flight of 1.0 hour in duration. The notation “BFR” was included with that entry. The logbook also contained an endorsement for the successful completion of a flight review on that date. The logbook noted a total flight time of 32,112.5 hours. Prior entries were made as block entries. Between June 1, 2008, and March 1, 2009, the pilot had logged 1,190 hours flight time, all in agricultural operations. The operator reported that the pilot had acquired 1,220 hours total time in AT-802 airplanes and “400+” flight hours within the previous 90 days, all in AT-802 airplanes. AIRCRAFT INFORMATION The accident airplane was a 1995 Air Tractor AT-802A, serial number 802A-0023. It was a single place, tail wheel equipped airplane used in agricultural application operations. The airplane was powered by a Pratt & Whitney PT6A-65R turbo propeller engine, serial number PCE-97172, rated at 1,295 shaft horsepower. According to maintenance records provided by the operator, an annual inspection was completed on March 19, 2009. The airframe and engine had accumulated 3,117 hours total time at the time of the annual inspection. METEOROLOGICAL INFORMATION The closest weather reporting facility to the accident site was located about 10 miles east-northeast at the Creston Municipal Airport (CSQ). The CSQ Automated Weather Observation System (AWOS), at 1115, recorded conditions as: Wind from 140 degrees at 8 knots, visibility 10 miles, scattered clouds at 3,200 feet above ground level (agl), scattered clouds at 5,000 feet agl, temperature 23 degrees Celsius (C), 20 degrees C, and altimeter 29.94 inches of mercury. The Schenck Field Airport (ICL) AWOS, located 26 miles southwest of the accident site, recorded weather conditions at 1115 as: Wind from 160 degrees at 5 knots, visibility 10 miles, scattered clouds at 5,000 feet agl, temperature 24 degrees C, dew point 20 degrees C, and altimeter 29.91 inches of mercury. The Red Oak Municipal Airport (RDK) AWOS, located 31 miles west of the accident site, recorded weather conditions at 1115 as: Wind from 090 degrees at 10 knots, visibility 7 miles, scattered clouds at 2,100 feet agl, temperature 22 degrees C, dew point 21 degrees C, and altimeter 29.89 inches of mercury. Weather surveillance radar (NEXRAD) images depicted a line of thunderstorms in the vicinity of the accident site. The Des Moines, Iowa, radar image, recorded at 1055, depicted a north-south oriented line of return echoes about 8 miles wide extending from central Adams County, southward through Taylor County in Iowa and into extreme northern Missouri. The northern end of this line was in the vicinity of Corning, Iowa, at the time. Additional echoes of equal or greater intensity were depicted extending north of the northern boundary of Adams County. The Des Moines NEXRAD image recorded at 1159 depicted the area of return echoes at the eastern boundaries of Adams and Taylor counties. The width of the line was approximately 10 miles at that time. The intensity of the echoes in the vicinity of the accident site (Adams County) remained approximately the same. The echoes depicted in southern Taylor County had diminished in intensity by that observation. WRECKAGE AND IMPACT INFORMATION The airplane impacted open rolling terrain on an easterly course. The elevation of the accident site was approximately 1,265 feet. The debris path was about 585 feet long by 230 feet wide. The initial impact ground scar was approximately 40 feet long. The airframe was fragmented. The right wing, fragmented sections of the left wing, the empennage and the flight control surfaces were recovered from the debris path. No evidence of an in-flight separation of any airframe component was observed. The engine separated from the airframe and was located at the east end of the impact ground scar. The propeller blades separated from the hub at the roots. The propeller hub remained attached to the engine. No anomalies consistent with a pre-impact failure were observed. MEDICAL AND PATHOLOGICAL INFORMATION An autopsy of the pilot was performed by the Iowa State Medical Examiner’s Office in Ankeny, Iowa, on August 17, 2009. The cause of death was attributed to multiple blunt force injuries sustained in the accident. The FAA forensic toxicology test report indicated the presence of ethanol in tissue samples. Testing of tissue samples was negative for all drugs in the screening profile. No blood sample was available for testing. ADDITIONAL INFORMATION The FAA Aeronautical Information Manual (AIM) notes that hypoxia is a "state of oxygen deficiency in the body sufficient to impair functions of the brain," and "the effects of hypoxia are usually quite difficult to recognize, especially when they occur gradually." The Pilot’s Handbook of Aeronautical Knowledge (FAA-H-8083-25A) adds that "one noteworthy attribute of the onset of hypoxia is that the first symptoms are euphoria and a carefree feeling." The AIM also states that between 12,000 and 15,000 feet "judgment, memory, alertness, coordination and ability to make calculations are impaired, and headache, drowsiness, dizziness and either a sense of well-being (euphoria) or belligerence occur. . . . Pilot performance can seriously deteriorate within 15 minutes at 15,000 feet. . . . At cabin pressure altitudes above 15,000 feet, the periphery of the visual field grays out to a point where only central vision remains (tunnel vision). The ability to take corrective and protective action is lost in 20 to 30 minutes at 18,000 feet and 5 to 12 minutes at 20,000 feet, followed soon thereafter by unconsciousness." FAA regulations (14 CFR 91.211) require a pilot to use supplemental oxygen when operating above 12,500 feet msl in excess of 30 minutes and during the entire flight time when operating above 14,000 feet msl. A representative of the operator stated that the accident airplane was not equipped with a supplemental oxygen system. He also reported that the pilot did not have portable oxygen equipment on-board with him on the accident flight.
The in-flight loss of control due to the pilot's impairment as a result of hypoxia. Contributing to the accident was the pilot's decision to operate the unpressurized airplane at an altitude requiring supplemental oxygen without having any oxygen available.
Source: NTSB Aviation Accident Database
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