Accident Overview
On June 19, 2016, at about 1440 central daylight time, a North American AT-6D, registration N150U, sustained substantial damage when it struck trees while maneuvering at low altitude near Henley, Missouri. The pilot and passenger on board received serious injuries. The airplane was registered to Ozark Management Inc. and operated by the pilot under 14 CFR Part 91 as a personal flight. Visual meteorological conditions prevailed, and no flight plan was filed. The airplane had departed from Jefferson City Memorial Airport (JEF) in Jefferson City, Missouri, at an unknown time for a local flight.
Witness Observations
A deputy with the Cole County Sheriff's Department reported that at about 1410, he observed an aircraft flying about 1,500 ft above ground level. He stated that the airplane performed a loop maneuver. The airplane then departed his view to the north behind his car. The deputy noted that the engine sounded like an "old P-51 Mustang." He was later notified of an accident at about 1445 and arrived at the scene about 1453, where he recognized the aircraft as the same type and markings he had seen earlier.
Another witness observed the airplane flying at low level over farm fields near her property. She stated that the airplane was so low it startled her horses as it flew overhead, and the engine was operating. She then observed the airplane fly inverted, but was unsure how long it remained inverted. Shortly after it went inverted, the engine became silent. The airplane lost altitude while inverted, and she heard a crashing sound as it impacted trees.
Aircraft Examination
FAA inspectors examined the wreckage at the accident site. The airplane had crashed into a wooded area, with the initial point of impact being a tree about 325 ft south of the main wreckage. The debris field extended about 300 ft south of the aircraft's final resting place, which was found inverted in a clearing. A strong odor of fuel and oil was noted. The left wing was separated from the fuselage and lying adjacent to it; the right wing had separated and was about 50 ft south. The main landing gear remained attached to the underwing structures and were retracted. The forward cockpit sustained significant impact damage; the pilot seat was intact but broken from its mount, with seatbelts intact. The instrument panel was broken, with most gauge glass broken, switches crushed, and all circuit breakers pushed in. The fuel selector was set to the 20-gallon reserve setting. The flap handle was up, the throttle full open, the mixture full rich, and the RPM setting mid-position. The rear cockpit had minor structural damage; the seat and seatbelts were intact. All cockpit glass was broken. The engine cowling was severely damaged. Propeller blades were bent aft with minimal scratching or nicks. The engine fuel filter had minor debris. The electric fuel pump operated properly when manually rotated.
Flight Manual Information
The North American AT-6D Flight Operating Instructions listed prohibited maneuvers, including outside loops, inverted flight exceeding 10 seconds, snap rolls above 130 mph, slow rolls above 190 mph, and spins/stalls when normal gross weight is exceeded. It also stated: "Inverted flying must be limited to 10 seconds because of engine difficulties resulting from prolonged inverted flight."
Post-Accident Interviews
FAA inspectors interviewed the pilot and passenger. Neither remembered what occurred during the accident, but both stated that no aerobatic maneuvers were flown during the flight. In a written statement, the pilot said, "Sightseeing trip, about 30 minutes into the flight the engine made a pop and the prop stopped. I was low from taking pictures of a friend's farm. We forced landed into a powerline cut. That's the last I remember." The pilot also suggested that corrosion of supercharger bearings could have caused the engine's loss of power, leading to oil starvation.
Weather Conditions
At 1353, the surface weather observation at JEF reported wind from 200 degrees at 10 knots, 10 miles visibility, few clouds at 5,500 ft, scattered clouds at 7,000 ft, temperature 32°C, dew point 19°C, and altimeter 30.17 inches of mercury.