francisco after hitting a seawall and the crash landing. new information released shows that the pilots had warnings the plane was descending too fast moments before the crash. >> reporter: this newly released security camera video shows asiana 214 crashing last july in san francisco. now we know more about what was happening inside that cockpit. it's clear the plane was descending too quickly, and today, we learned one of the pilots realized it. the cockpit voice recorder show 52 seconds before the crash, a relief pilot in the backseat of the cockpit called out sink rate, warning the plane was dropping too fast. yes, sir, the pilot flying responded and that warning was repeated two more times, once in english and finally in korean. the pilot at the control lee kang cook was a trainee on the 777 but had substantial experience in other aircraft.