Flight History
On June 10, 2019, at about 1020 central daylight time, a Cessna 425, registration N622MM, was destroyed in an accident near Butler, Missouri. The private pilot, who sustained fatal injuries, was conducting a cross-country flight under Part 91. The flight had departed Vero Beach, Florida, at 0554 eastern daylight time, with a planned destination of New Century Airport in Olathe, Kansas. After an uneventful 970-mile flight, the pilot began a descent and was in communication with air traffic control.
Around 1004 central daylight time, the pilot reported a "major problem" and stated he could not retard the right engine throttle. The controller observed the airplane climbing and descending. At 1008:32, the controller acknowledged the engine trouble, and the pilot said he would need to shut down the right engine while it was at full power. The pilot then indicated the airplane could make the airport, but might need to shut down the engine on final approach.
At 1011:54, the pilot reported operating on one engine. He requested the nearest airport, and the controller advised Butler Airport (BUM) was about 8 miles away. The pilot stated he would land on runway 18 at BUM and later reported the airport in sight. At 1017:45, the pilot said he was trying to regain control. The controller cleared the airplane for a visual approach. Between 1018:53 and 1019:08, the pilot advised that the airplane was "gonna go down" on the highway. No further transmissions were received.
Radar data showed the airplane made a 360° right turn at about 2,500 ft mean sea level, with the last data point at 1,300 ft.
Witness and Impact
A witness driving on the highway observed the airplane low and slow, with both propellers spinning and no smoke. She saw it flying northeast to southwest before it suddenly descended nose-first into the ground. The airplane impacted a gravel road adjacent to a 100-ft-tall grain silo, about 1 mile from the highway and 3.3 miles from Butler Airport.
The initial impact was with the right wing tip in a nose-down, right-wing-low attitude. The right engine/nacelle struck the ground between the road and the silo. The left wing struck a steel staircase on the silo's exterior, and both main landing gear contacted the silo, leaving tire marks 20 to 30 ft up. A fragment of aluminum was found 30 ft up, and a left propeller blade left paint smears 15 ft up. The nose struck an air cycle machine at the silo's base before the airplane cartwheeled onto the left engine and came to rest inverted about 30 ft from the initial impact.
Wreckage Examination
The landing gear were found extended, and the flaps were positioned about 10° nose down. Flight control continuity was established. The fuel selector handles were in cross-feed positions (left selector in right main, right selector in left main). The right engine power control lever was full forward, the propeller condition lever about 0.25 inch from minimum, and the fuel lever in cutoff. The left engine power lever was full forward, propeller condition lever about 0.50 inch back from maximum, and fuel lever in run. Control linkages were impact damaged but no rigging anomalies were found.
Teardown examinations of both engines revealed no mechanical anomalies that could have prevented normal operation. The fuel control units (FCUs) showed no pre-existing mechanical anomalies, though some contaminants were found in the Py air sections, but no restrictions or blockages in the Py bleeds. Fuel pumps, propeller governors, and overspeed governors also had no anomalies.
According to the Cessna 425 single-engine performance chart, the airplane could maintain level flight with one engine inoperative if the landing gear and flaps were retracted and the inoperative engine's propeller was feathered. The right engine propeller condition lever was not found in the feather detent position.
Medical Information
An autopsy determined the pilot's cause of death as multiple blunt force trauma. Toxicology testing detected dextromethorphan, its metabolite dextrorphan, rosuvastatin, and metoprolol in blood and urine. Ramipril, acetaminophen, salicylate, and ibuprofen were found only in urine. All medications are considered non-impairing. No ethanol was detected.