After departing the Baltimore-Washington Airport, the aircraft had climbed to FL 220. According to information on the cockpit voice recorder (CVR), the crew experienced gyro problems during the climb. They selected the #1 vertical gyro to drive both approach horizons (attitude indicators), since there was an indication of a malfunction in the #2 vertical gyro system. About 7 minutes after leveling at FL 220, the flight was cleared to the Dryer VOR. Shortly after that, there were indications of confusion in the cockpit which included the statements, "What's happening here," "You got it?" and "No." The aircraft entered a right descending spiral; the indicated airspeed increased from approximately 205 to 317 knots; then an in-flight breakup occurred. The wreckage was found scattered over an area approximately 2 miles long by 1 mile wide. An examination of the wreckage revealed that the in-flight structural failure had occurred due to overload, then a fire ignited in the right wing after it had failed. The aircraft was not equipped with an independent standby attitude indicator.