Introduction
A cross-country flight of a light business jet carrying an airline transport pilot and a passenger ended in an inflight breakup after the pilot reported problems with the flight instruments. The flight took place in instrument meteorological conditions and lasted approximately 10 minutes according to radar data.
Flight Sequence
About one minute after departure, air traffic control instructed the pilot to climb and maintain 14,000 feet mean sea level. Three minutes later, the pilot communicated that the flight management system had failed. Shortly after, he requested a climb, stating he was "trying to get to clear skies." The controller provided headings and altitudes to vector the airplane into visual meteorological conditions. During subsequent transmissions, the pilot reported that he was "losing instruments," was hand-flying the airplane (likely with an inoperative autopilot), and wanted to "get clear of the weather."
Radar data indicated a series of climbs and descents with large variations in airspeed. About two minutes before radar contact was lost, the airplane entered a climbing right turn, reaching a peak altitude of approximately 21,000 feet, before beginning a rapidly descending and tightening turn.
Loss of Control
Performance data showed that during the descending turn, the airplane became partially inverted, exceeded its design maneuvering speed, and reached a peak descent rate of about 36,000 feet per minute. Radar contact was lost at approximately 16,000 feet mean sea level. The airplane subsequently experienced an inflight breakup. The wreckage was distributed over a debris path about three-quarters of a mile long and one-third of a mile wide.
Postaccident Examination
Examination and testing of the flight instruments did not identify what may have caused the anomalies the pilot reported. All airframe structural fractures were consistent with ductile overload, and no preexisting conditions were found in the airframe or either engine. The airplane was equipped with three separate attitude information sources, each powered by different sources. Investigators considered it unlikely that all three would fail simultaneously. In the event of a dual failure of attitude instrumentation on both pilot and copilot sides, airplane control could have been maintained by reference to the standby attitude indicator, and heading information was available from the standby compass. The pilot did not specify the exact nature of the difficulties to the controller, but clearly perceived the situation as requiring an urgent ascent to visual conditions. As a single pilot operating without assistance in a high-workload, high-stress environment, he would have been particularly susceptible to distraction and ultimately loss of control due to spatial disorientation.