(CNN) -- A Delta commuter flight carrying 50 people crashed Sunday morning near Blue Grass Airport in Lexington, Kentucky, airport and airline officials said. One person is known to have survived.
That person is being treated at the University of Kentucky Hospital, according to the hospital spokeswoman.
"He is in critical condition," Gail Hairston said, without adding any other details.
There were 46 passengers, three crew members and one off-duty crew member on Delta Flight 5191 -- operated by Delta's commuter carrier, Comair, according to Michael Gobb, director of the Blue Grass Airport.
Gobb said it is still unclear how many people perished in the crash because "search operations are still going on."
Initial reports from first responders indicated all 50 people on board died in the crash, Federal Aviation Administration spokeswoman Laura Brown told CNN.
The commuter flight was en route from Blue Grass Airport to Atlanta's Hartsfield-Jackson International Airport, Federal Aviation Administration spokeswoman Laura Brown told CNN.
The plane crashed a mile from the airport shortly after take-off, the FAA said.
The aircraft was a Bombardier Canadian Regional Jet (CRJ)-100, which has a good track record, according to its history on the National Transportation Safety Board's Web site.
Flight 5191 was cleared for takeoff at 6:05 a.m. ET, which was the last communication between the pilot and air traffic controllers, FAA officials said.
The plane crashed at 6:19 a.m. ET, about a mile west of the airport, FAA officials said.
The plane was scheduled to land in Atlanta at 7:18 a.m. ET.
It is unclear what caused the crash. There were no reports of bad weather in the Lexington area.
"It was dark at the time of the accident, but it was clear," Brown said.
A team of National Transportation Safety Board investigators is heading to the crash site to begin an investigation.