What happened
While cruising at FL370, the aircraft encountered clear air turbulence linked to a nearby level 6 thunderstorm. This encounter triggered an upset that led the aircraft into a convective cell characterized by lightning, severe icing, and extreme turbulence. During this period of uncontrolled descent through the storm, both engines experienced flameouts. The crew attempted recovery maneuvers, but the intense environmental conditions prevented success.
As the aircraft emerged from the bottom of the thunderstorm at 4,000 feet, the flight crew subjected the airframe to excessive stress. This resulted in the separation of the left main landing gear door, which struck the left horizontal stabilizer and caused the component to fail due to overload. The aircraft ultimately impacted the ground with a nose-down pitch of 82 degrees. There were seven fatalities among the occupants.
Findings
Investigations identified several contributing factors related to both weather and operational procedures. The aircraft encountered severe meteorological conditions, including heavy gusts, downdrafts, and thunderstorm activity during night operations. Additionally, the crew was operating with a known deficiency in equipment, as they had previously reported a malfunction regarding the onboard weather radar.
Operational failures were also noted regarding flight service station (FSS) communications. The crew received an inadequate briefing that failed to include critical SIGMET and AIRMET information. Furthermore, the investigation highlighted that the pilot in command faced excessive workload during the emergency, and the FSS provided unclear information and failed to issue necessary hazardous weather advisories.