CEN24FA010 · Cessna 414 UNDESIGNAT

The airplane landed at the airport and the pilot taxied to the ramp, boarded the passenger without shutting down the airplanes’ engines, then taxied back out to the runway and the airplane departed. Video footage captured part of the accident sequence, showing the airplane descending in an extreme, nose-low attitude while rolling through inverted, consistent with uncontrolled flight, and impacting a field near the departure end of the runway. A witness, who was driving in her vehicle near an intersection just to the west of the airport, observed the airplane shortly after it departed from the runway. She observed the airplane was “tilted to the left,” turned on its side, and then entered a nosedive. She observed the airplane impact a field, explode, and both the wreckage and surrounding area caught fire. Examination of the airframe did not reveal any preimpact mechanical malfunctions or failures. During the examination, the elevator trim was found in a significant nose up position. The elevator trim was likely left at the setting from when the airplane landed at the airport just prior. While the pilot might have been distracted with getting the passenger settled in the airplane, and/or may have been in a rush, the investigation was unable to determine why the pilot did not set the elevator trim before takeoff. The takeoff checklist for the airplane included instructions to properly set the trim tabs before takeoff. The elevator trim position likely resulted in the airplane's nose-up attitude, which led to an exceedance of the airplane's critical angle of attack and an aerodynamic stall during the takeoff. While multiple valve springs from the right engine were found fractured from fatigue cracking, examination of the propellers showed the degree of damage was similar between left and right propellers, suggesting engine power symmetry at the time of impact. For example, chordwise/rotational scoring, leading edge gouging, and blade retention pocket damage indicated rotation at the time of impact. Internal impact marks indicated the propeller blade angle was in the low range of normal operation during the impact sequence. The damage signatures were consistent with forceful rotation toward low blade angle and at low to moderate power condition on both propellers at the time of impact. The pilot had a history of high blood pressure and diabetes. There is no evidence that these conditions were causing impairment at the time of the accident, although they do indicate somewhat elevated general cardiovascular risk, autopsy assessment of which was limited by injury. The pilot also had used the antidepressant medication sertraline, which was not among the medications reported at his last aviation medical examination. Whether he was experiencing any impairing effects of an underlying condition such as depression, or any adverse side effects of sertraline use, is unknown.

Verbatim NTSB analysis and probable cause from the NTSB dataset