From The Birmingham News:
Cockpit voice recordings show the pilots were cleared to land on Runway 18/36 two minutes before the end of the recording, Sumwalt said. Sixteen seconds before the end of the recording, the pilots received the first of two "sink rate" warnings, a mechanism which kicks in if the plane's descent does not match its programmed path, he added. Thirteen seconds to the end, one crew member reported the runway was in sight. Nine seconds prior to the end, there are "sounds that are consistent with impact," Sumwalt said.