What happened
Before departing Nashville, the pilot obtained weather information through a commercial weather service at flight operations; however, the specific details of this briefing are unavailable. At 1839, the pilot contacted the Nashville Automated Flight Service Station (AFSS) for a weather update.
The flight departed Nashville for Knoxville at 2000. At 2205, the aircraft departed Knoxville to begin the return trip to Nashville. There is no documentation of any weather briefings occurring after the 1839 update.
At 2238, the pilot reported encountering light ice. For approximately 10 minutes following this report, the pilot continued to request lower altitudes. During this period, the aircraft was lost from radar.
Former pilots of the operator indicated a pattern of operational pressure, stating that crews were routinely threatened with punitive action if they refused to fly in questionable weather or in aircraft with questionable airworthiness.