A South Korean government official says the control tower at San Francisco International Airport did not warn the captain of Asiana Airlines Flight 214 how slow it was flying before it crashed.

Choi Jeong-ho, a senior official at the Ministry of Land, Infrastructure and Transport, said at a news conference Thursday that the analysis of communications between the pilot and the control tower shows the air traffic controller gave no warning of the jet's airspeed or altitude as it made its approach. 

Choi said that air traffic controllers sometimes provide necessary information to pilots, adding that it will be possible to determine whether there were problems with air traffic control when the roles and duties of controllers that day are clearly fleshed out.

Choi dismissed U.S. National Transportation Safety Board’s comment that it is customary that supervisory training pilots sit on the left in the cockpit.

He said it is an international norm that trainee pilots sit on the left, while the supervisory pilot sits on the right during training flights.