ERA22LA395 · Diamond Aircraft Industries DA 42 NG

The commercial pilot and his flight instructor were preparing to depart on a local flight when the accident occurred. They taxied to the runway and continued the pre-takeoff and engine runup tasks. While at the holding pad, the weather deteriorated significantly to include thunderstorms, heavy rain, and high wind gusts to 54 knots. The pilots elected to hold their position to wait until the weather conditions improved. The instructor applied down elevator control and moved the left aileron into the wind. Review of available weather data indicated that a microburst caused the left wing to raise and the airplane rolled over, coming to rest inverted. The flight instructor in the left seat was seriously injured, and the commercial pilot in the right seat was fatally injured. The airplane was substantially damaged. The surviving flight instructor reported that they received a weather briefing before the flight and that there was a small area of precipitation about 7 miles to the south, slowly moving north; they expected the area of precipitation would be in the vicinity after their departure. He stated that the cell did not appear to be developing significantly when observed on their radar. An examination of meteorological data revealed that the pilots requested and received a weather briefing from a commercial flight planning service about 1 hour and 18 minutes before the accident. The briefing included convective SIGMETs for the area. The surface observations received included wind gusts to 36 knots and thunderstorms in progress to the south. If the pilots had checked the current weather at the airport 7 miles to their south before taxiing, they would have noticed that the weather there was deteriorating rapidly. The examination of the weather products revealed that the pilots were provided and reviewed the weather information that they encountered. The wreckage was examined to determine the survivability aspects of the accident. The cockpit canopy was crushed and the overroll bar was fractured. About 4.4 inches of vertical space between the middle floor tunnel cover and the overroll bar was lost. The cockpit seats and restraints were undamaged. The amount of force applied to the airframe during the upset event could not be determined. The rolling motion of the airplane likely moved the pilots out of position before impact. This change in position, in conjunction with the decrease in occupiable space from the overhead structure deformation and stretch of the seat belts, caused the injuries sustained by the occupants.

Verbatim NTSB analysis and probable cause from the NTSB dataset