According to National Transportation Safety Board member Debbie Hersman, Comair Flight 5191 had been cleared to use a 2.1 kilometre runway suited for jets, known as runway 22, at Lexington's Blue Grass Airport.
Instead, the plane bound for Atlanta on Sunday morning, took runway 26, which is half as long as runway 22 and was unlit because its runway lights were out of service.
The jet then went down during takeoff and burst into flames about 1.6 kilometers west of the airport. Only the co-pilot survived the crash and fire.
Ms Hersman said the pilots and the air traffic controller never discussed runway 26, which is not intended for commercial flights as it is much too short for a takeoff by the 50-seat Bombardier jet.
She also said she did not know if the lights on were lit on the longer runway. The airport's director has said the longer runway had recently undergone refurbishing.
"One of the issues that we're certainly going to be looking at is the visibility and the ability for the crew to see," Ms Hersman said. "And also the issue of whether or not air traffic control could see."
The airport tower was staffed at the time of the accident by a lone Federal Aviation Administration air traffic controller, an FAA spokesman said.
Simulation planned
Ms Hersman also reported that preflight preparations were normal and the aircraft, a CRJ-100 made by Montreal-based Bombardier Inc, was deemed airworthy before takeoff.
"Finally, the takeoff roll began and the airplane continued to accelerate until the recording stops," she said.
Several teams are investigating different aspects of the crash, including visualising the situation from the pilot's vantage point, Mr Hersman said.
"There are often issues that present themselves, whether weather or darkness or other things that could have obscured the view," she said. "We will take all of those things into consideration and that's why we are going to attempt to simulate similar conditions at the same time of day."