Misfueling Leads To Disaster in Kokomo, Indiana

On Oct. 5, 2019, at about 10 a.m., the pilot landed the Piper Aerostar he was flying at the Kokomo Municipal Airport (KOKK). It's a non-towered general aviation airport with two paved runways, one 6,000 feet and one 4,000 feet long. The Piper Aerostar 602P is a sleek-looking, pressurized mid-wing five-seat piston propeller plane. The pilot, who was not the owner, was using the plane to get him from Tampa, Florida, to Kokomo for a day of training with another client in a different airplane. He parked the twin at the fixed-base operator (FBO), where it was refueled.

The accident pilot spent the day conducting recurrent training and a Flight Review to the Part 91 contract pilot in a Piper PA-42 Cheyenne, a twin-turboprop airplane. She said he was cheerful, enthusiastic about flying, and they spent the day doing systems ground school, a detailed preflight and a busy hour of flight training maneuvers. With that successfully over, at about 4 p.m., the pilot planned to fly the Aerostar home to Tampa, Florida.

The student said he was "very chipper." She dropped him off at the plane and saw him visually inspecting the fuel tanks. She drove away when he gave her a "thumbs-up" signal. She later heard the engines start, remembering they "sounded normal." An FBO employee inside also heard the engines start and said they sounded "typical." The weather was benign, with clear skies, light winds and the temperature 72 degrees Fahrenheit. He used Runway 14 to takeoff to the south.

A witness, driving a car along a road next to the airport, saw the plane flying low. It made a sharp left turn, dipped the left wing, and then disappeared from sight. Landing gear in the up position, just 3 miles from the airport, it had crashed into a flat soybean field. The mangled, inverted debris spread along a line over 300 feet long. There was no fire, but the plane was destroyed. The pilot died in the crash.

Months after the accident, the Safety Board determined that the "wreckage and wreckage path displayed features consistent with an accelerated stall." The pilot may have been turning back to the airport. Low, slow!stalled it in. But long before that detailed analysis was available, the wreckage investigators had immediately discovered the defining cause.

Fuel samples taken from the fuel tanks were completely clear. So was the liquid taken from the fuel line to the right engine fuel manifold valve. And the liquid in the line to the left engine fuel manifold valve. Investigators noted all the fuel recovered had the color, viscosity, oiliness and odor of Jet A kerosene. It certainly wasn't the blue color that signifies the 100LL gasoline required for reciprocating piston engines. 

The FAA Airplane Flying Handbook says, "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."

The Aerostar had, indeed, been fueled with Jet A kerosene. It was, investigators determined, an intentional action. It was, in fact, what the line service technician thought the pilot wanted. The college senior, majoring in communications, asked the pilot on the radio if he needed parking and jet fuel. The pilot said yes. After the Aerostar was parked, the fueler drove up in the large, clearly marked Jet A truck. He thought the slick mid-wing twin was a jet, which is why he asked about jet fuel. The fueler told the NTSB that he asked the pilot again if he was wanted jet fuel, and the pilot said "yes." Two mistakes then happened: The fueler put Jet A into the tanks, and the pilot never noticed.  

This was the fueler's first job in aviation. He was trained by the FBO and said that training did include the fact that Jet A fuel would destroy a reciprocating engine. But maybe he didn't receive enough training on the sometimes-subtle visual differences between piston and turboprop engines. He told the NTSB that he asked the pilot if he needed jet fuel, and the pilot said yes. Still, it shouldn't have been possible to fill an Aerostar with jet fuel. Because in addition to color-coded labels and signs on trucks and fueling ports, there is an engineering fix to prevent this exact event.

Back in the 1970s, you could easily fuel a piston airplane using a jet fuel nozzle. Following a famous misfuelling accident with R. A. "Bob" Hoover, a robust mechanical fix was adopted industrywide. The fueling ports on piston-engine aircraft were made smaller, less than 2.36 inches in diameter. And the spouts of jet fuel dispensers were flattened and widened to be at least 2.66 inches long. It is physically impossible to put a jet fuel nozzle into most non-turbine engine aircraft fuel tanks. So what happened in Kokomo?

The fueler told the NTSB he was able to fuel the Aerostar by "orienting the Jet A fuel truck's fuel hose nozzle about 90 degrees to the wing fuel filler ports and about 45 degrees to the fuselage fuel filler ports." He said that initially, he spilled about 1 gallon of Jet A during the fueling, but by adjusting his technique, subsequent fuel spillage was minimal. The nozzle didn't go in the filler port, but the fuel was carefully poured into the tank. The fueler diligently worked around the engineering fix. But why didn't the pilot catch the error?

It wasn't inexperience or lack of training. He started flying as a teenager, soloing at 16 and getting a private pilot license at 17. The 59-year-old held an Airline Transport Pilot certificate, with a Citation Jet type rating. He was also rated to fly the L-39, a Czechoslovakian high-performance military jet trainer. He used to own one. He built his first plane in college, a Pitts S-1C, which he sold to buy his wife her engagement ring. Later, there would be others, including a Seneca, a Baron and an Extra 330LX. He had 7,500 total flight hours, was an active flight instructor, and had been an FAA-designated pilot examiner.

It wasn't a lack of intelligence or education, either. After getting his undergraduate degree at Princeton, he went to medical school at Yale and then medical specialty training at Harvard, becoming a successful plastic surgeon. He was active in private practice, specializing in cosmetic, hand and microvascular surgery. After the accident, fellow surgeon and pilot Dr. Dick Karl told the Tampa Bay Times newspaper, "He was a consummate airman, he was a guy who loved aviation in all forms. He pursued jets, he pursued aerobatics---he was a guy who loved to fly as much as he loved to breathe."

His flying history wasn't flawless. In 2008, in his Extra 300, on a visual approach to land at the Peter O Knight Airport (KTPF) close to Tampa, he got so low that the wing clipped the mast of a sailboat in the water. He made it to the airport, suffering a broken hand. His passenger broke a leg in the impact, and the aircraft was substantially damaged. In 2016, the FAA ended the pilot's designation as a pilot examiner "due to sub-standard performance while conducting examinations." In an aviation magazine profile, he is credited with 10,000 flight hours that same year. However, on his 2018 FAA medical form, he reported having 7,500 hours. His widow did not release his logbooks to the NTSB for review despite two requests.

Did he request jet fuel? We'll never know for sure. And there's no record, or witnesses, for us to know if the pilot drained the fuel system to check for water or jet fuel during his preflight checks. We'll never know if he saw the blue color of 100LL or the clear color of jet fuel or skipped this step entirely.

There are other ways to catch a fueling error. Pilots are advised to supervise fueling operations. He could have checked the fuel receipt. Pilots of cabin-class twins and other airplanes that look like they could have turboprop engines should be especially aware of the danger of this kind of misfuelling. Whatever he did or didn't do, he taxied out and took off.

The NTSB determined the probable cause of the crash to be "the pilot's exceedance of the airplane's critical angle of attack following a dual engine power loss caused by the line service technician fueling the airplane with the wrong fuel." They also found contributing to the accident "was the pilot's inadequate supervision of the fuel servicing." Last year, the airport and FBO paid the pilot's estate $700,000, the maximum amount allowable under Indiana tort law, to end a wrongful death negligence lawsuit. 

Do you want to read more After the Accident columns? Check out "Three Plane Crashes Into Power Lines And Why They Happened" here.