HISTORY OF FLIGHTOn October 5, 2019, about 1637 eastern daylight time, a Piper Aerostar 602P, N326CW, was destroyed when it was involved in an accident near Kokomo, Indiana. The airline transport pilot was fatally injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 business flight. According to the airport employee who fueled the airplane, during the pilot’s approach to the Kokomo Municipal Airport (OKK), Kokomo, Indiana, he asked if the pilot wanted jet fuel, and the pilot said "yes." He said that the airplane looked like a jet airplane. When the airplane arrived, the employee parked the Jet A fuel truck in front of the airplane while the pilot was still inside the airplane. The employee said that he asked the pilot again if he was wanted jet fuel, and the pilot said "yes." The employee fueled the airplane with about 163 gallons of Jet A from the fuel truck. The employee said that he was able to orient the different-shaped nozzle (relative to the 100 low lead fuel truck nozzle) from the Jet A fuel truck by positioning it 90° over the wing fuel tank filler necks and about 45° over the fuselage filler necks. He said that he initially spilled about 1 gallon of fuel during refueling and adjusted his technique so subsequent fuel spillage was minimal. The student pilot, who received recurrent training from the accident pilot, said that when she arrived in her vehicle to meet the accident pilot, he was walking between the fuel truck that was parked by the airplane and her vehicle. She said that the accident pilot began training right away about 1045. They completed training, and after 1630, the student pilot drove the accident pilot to the airplane. The student pilot said the accident pilot visually checked the fuel tanks of the airplane to ensure they were fueled up and gave a "thumbs-up" to the student pilot. The student pilot did not stay for the rest of the accident pilot's preflight inspection and drove off. The student pilot heard the engines start and "they sounded normal." The student pilot did not see the takeoff. The student pilot said the winds favored runway 14, which was in use on the day of the accident. A witness, on a nearby road, stated that she saw a "low flying" airplane flying from north to south. The airplane made a "sharp left turn" to the east. The left wing "dipped low" and she then lost sight of the airplane, but when she approached the intersection near the accident site, she saw the airplane on the ground. The airport employee said that he was inside the fixed base operator building about 1620 when he heard the engines start. After the engines started, the engines sounded "typical." He said that he did not hear any radio transmissions from the pilot during his departure and did not hear an engine runup. PERSONNEL INFORMATIONThere were no pilot records provided to the National Transportation Safety Board (NTSB) Investigator-in-Charge (IIC) indicating the pilot's flight experience and a recent flight review as required under Part 61.56 received from the accident pilot's wife after two requests were made to her. On November 28, 2008, the pilot was involved in an aviation accident that was investigated under NTSB accident identification number: ERA09CA073. On December 2, 2016, the Federal Aviation Administration terminated the pilot's designation as a pilot examiner due to sub-standard performance while conducting examinations. On November 9, 2018, the pilot reported his flight experience that included 7,500 total hours and 200 hours in last six months as of his last airman medical exam. AIRCRAFT INFORMATIONThe owner of the accident airplane stated he was supposed to receive initial training in the airplane from In Flight Review, Inc., but it never happened for "various reasons." He stated that he never gave permission for the accident pilot to fly the airplane. The owner declined to provide more information as who he gave the airplane keys to. AIRPORT INFORMATIONThe owner of the accident airplane stated he was supposed to receive initial training in the airplane from In Flight Review, Inc., but it never happened for "various reasons." He stated that he never gave permission for the accident pilot to fly the airplane. The owner declined to provide more information as who he gave the airplane keys to. WRECKAGE AND IMPACT INFORMATIONOn-scene examination of the airplane revealed the airplane wreckage path was about 328 ft in length along an approximate heading of 046° on a dry and hard surfaced fallow bean field. The wreckage and the wreckage path displayed features consistent with an accelerated stall. On-scene examination revealed the presence of a clear liquid consistent in color, viscosity, oiliness, and odor with that of Jet A jet fuel in a fuselage tank and in the fuel lines leading to the fuel manifolds of both engines. Several of the engine spark plugs exhibited damage consistent with detonation. Flight control continuity was confirmed. The landing gear was in the retracted position. ADDITIONAL INFORMATIONThe Airplane Flying Handbook (FAA-H-8083-38), Chapter 2, Ground Operations, stated in part: "Jet fuel has disastrous consequences when introduced into AVGAS burning reciprocating airplane engines. A reciprocating engine operating on jet fuel may start, run, and power the airplane for a time long enough for the airplane to become airborne only to have the engine fail catastrophically after takeoff. Jet fuel refueling trucks and dispensing equipment are marked with JET-A placards in white characters on a black background. Because of the dire consequences associated with misfueling, fuel nozzles are specific to the type of fuel. AVGAS fuel filler nozzles are straight with a constant diameter. However, jet fuel filler nozzles are flared at the end to prevent insertion into AVGAS fuel tanks. Using the proper, approved grade of fuel is critical for safe, reliable engine operation. Without the proper fuel quantity, grade, and quality, the engine(s) will likely cease to operate. Therefore, it is imperative that the pilot visually verify that the airplane has the correct quantity for the intended flight plus adequate and legal reserves, as well as inspect that the fuel is of the proper grade and that the quality of the fuel is acceptable. The pilot should always ensure that the fuel caps have been securely replaced following each fueling." "During refueling operations, it is advisable that the pilot remove all passengers from aircraft during fueling operations and witness the refueling to ensure that the correct fuel and quantity is dispensed into the airplane and that any caps and cowls are properly secured after refueling." On-scene inspection of the fuel truck used to refuel the airplane revealed that the truck had markings "JET A.".