What happened
At 06:34 MST, the pilot filed a VFR flight plan for a route from El Paso to Tucson. Prior to departure, the pilot was advised of two pilot reports (PIREPs) indicating severe turbulence in the Tucson area, as well as an AIRMET concerning turbulence below 12,000 feet.
The aircraft's takeoff and initial departure appeared normal; however, there was no further communication from the airplane following the departure phase. While en route, the aircraft underwent an in-flight breakup. There were no known witnesses to the event.
The investigation
Investigators located the right outboard wing panel approximately 2/10 mile from the main wreckage site. Examination of this component provided evidence that it had failed due to positive (upward) loading.
The outboard two-thirds of the left horizontal stabilizer had also separated from the aircraft, though this piece was not recovered. Evidence indicated that this component had failed due to downward loading.
Additionally, a park ranger reported observing a black, dome-shaped cloud over the mountains approximately 5 miles from the crash site, which was capped by another smaller cloud at a higher elevation. While information existed prior to the flight that could have been used to determine severe turbulence, the National Weather Service had not issued an advisory for such conditions.