ERA18FA167 · Raytheon Aircraft Company 58 UNDESIGNAT

The private pilot, who was not instrument current, and a passenger departed on an instrument flight rules flight into instrument meteorological conditions. After takeoff, the pilot did not climb to the clearance altitude of 2,000 ft mean sea level (msl), instead leveled off about 500 ft msl. The pilot then began a second climb to a maximum altitude of 1,400 ft, then leveled off, followed by a steep right descending turn to about the base of the clouds about 400 ft. The airplane then began a climb to 1,700 ft msl while the airspeed decreased. While flying in a right bank near the published wings-level, 1-g stall speed, the airplane likely exceeded its critical angle of attack, stalled, and entered a descent. A witness reported hearing a loud engine sound from the low-flying airplane, and last observed the airplane in a slight left bank, although the airplane impacted the ground in a nose and right-wing low attitude.

Examination of the flight controls, engines, engine systems, and propellers revealed no evidence of preimpact failure or malfunction. While postaccident acceptance testing of autopilot components revealed minor out-of-tolerance conditions, the conditions noted would not have adversely affected proper operation. Although the presence of moisture in the static system could not be ruled out because the static system was destroyed, it is unlikely that was an issue because the ADS-B data for pressure altitude and geometric altitude calculated by the GPS revealed no gross difference.

The restricted visibility, maneuvering during the transition from takeoff to cruise flight, and the pilot's lack of instrument proficiency provided conditions conducive to the development of spatial disorientation. The airplane's altitude and track variations were inconsistent with its takeoff and departure clearance and the high velocity impact are consistent with the known effects of spatial disorientation. Therefore, it is likely that the pilot became spatially disoriented while flying in instrument meteorological conditions and lost control of the airplane. Contributing to the loss of control was the pilot's lack of recent instrument experience.

Verbatim NTSB analysis and probable cause from the NTSB dataset