Flight Preparation
The pilot obtained three weather briefings prior to departure. These briefings indicated significant convective activity and a moving squall line along the planned route, with forecasts predicting substantial thunderstorm activity. Concerned about the weather, the pilot planned to use onboard weather radar to find "holes" to maneuver around the storms, and elected to fly a more southerly route to avoid severe weather.
Departure and Weather Avoidance
After departure, radar data showed the pilot flying a southerly course west of the severe weather. The pilot then requested a 150-degree heading from air traffic control, intending to steer toward a visible "hole" in the weather. A controller, who also reported seeing a hole, instructed the pilot to fly a 120-degree heading and proceed direct to a fix along the route of flight.
Final Encounter
The aircraft entered a line of very heavy to intense thunderstorms during cruise at 25,000 feet. It began to lose altitude and reverse course, then entered a rapid descent, broke up in flight, and impacted terrain. Review of precipitation data revealed substantial information available to the controller regarding moderate to extreme weather along the flight path. While the first controller stated he saw a clear area ahead, this was contradicted by recorded data and a second controller working the D-position. The first controller did not advise the pilot of the severe weather on the new heading. After entering the severe weather, the pilot lost altitude; when queried by the controller, the pilot reported encountering "pretty good turbulence." This was the last communication before the aircraft disappeared from radar. The controller did not provide advisories regarding the adverse weather's immediate safety hazard as required by Federal Aviation Administration Order 7110.65.
Wreckage Examination
Examination of recovered flight control surfaces revealed that all fractures were consistent with overstress failure. No evidence of preexisting cracking was found, and no preaccident anomalies were noted with the engines.