Comair Flight 5191 (marketed as Delta Connection Flight 5191 under a codeshare agreement with Delta Connection), was a scheduled United States domestic passenger flight from Lexington, Kentucky, to Atlanta, Georgia. On the morning of August 27, 2006, at around 06:07 EDT (10:07 UTC),: 1  the Bombardier Canadair Regional Jet 100ER crashed while attempting to take off from Blue Grass Airport in Fayette County, Kentucky, 4 miles (6.4 km) west of the central business district of the city of Lexington.

The aircraft was assigned the airport's Runway 22 for the takeoff but used Runway 26 instead. Runway 26 was too short for a safe takeoff, causing the aircraft to overrun the end of the runway before it could become airborne. It crashed just past the end of the runway, killing all 47 passengers and two of the three crew. It was the second-deadliest accident involving the CRJ-100/-200; two years earlier, China Eastern Airlines Flight 5210 claimed 53 lives.The flight's first officer, James Polehinke, was the pilot flying at the time of the accident and was the sole survivor. In the National Transportation Safety Board's report on the crash, investigators concluded that the likely cause of the crash was pilot error.