At 500 feet there was an audible automated altitude alert. The airspeed was about 134 knots. At this point that pilots realized they weren't properly lined up with the runway, Hersman said.
"Between 500 and 200 feet, they had a lateral deviation and they were low. They were trying to correct at that point," she said.
At 200 feet and another automated altitude call out, the airspeed had slowed to 118 knots — well below the target level.
At this point, U.S. pilots would typically call for an aborted landing because the plane was more than 5 knots below its target speed, Collins said. But at no point in between 500 and 100 feet does the voice recorder show the pilots making any comment related to airspeed, Hersman said at a briefing Thursday.
Hersman said at earlier briefings that it was not until 200 feet — 16 seconds before impact — that Lee Jeong-Min, the instructor pilot "recognized the auto-throttles were not maintaining speed."
At 125 feet and 112 knots, both throttles started moving forward, indicating more fuel was being sent to the engines to increase power and speed. That was eight seconds before impact. Even if the autothrottles weren't fully turned on, either of the pilots in the two front seats could reach down and manually push the throttle levers forward to increase power.
It was about this time that the cockpit voice recorder indicated the first officer — the third pilot seating behind the front two pilots — realized the plane was traveling too slowly and called for an increase in speed.
A second later, Lee Gang-kuk's yoke can be heard rattling violently on the voice recorder. This is the sound of a stick shaker going off, a piece of safety equipment that tells a pilot the plane is about to stall because it has slowed to a dangerous speed and lost lift.