The National Transportation Safety Board said the plane's speed at landing should be 137 knots, but fell below that before the crash.

82 seconds before impact: Plane's altitude is about 1,600 feet (488 metres). Autopilot is disengaged. Speed not given. The plane is configured for approach and proceeds normally with "no discussion of any aircraft anomalies or concerns," NTSB Chairman Deborah Hersman later says.

73 seconds: Air speed slows to 170 knots. Altitude is about 1,400 feet.

54 seconds: Speed falls to 149 knots, altitude down to 1,000 feet.

34 seconds: Speed falls to 134 knots, below safe landing target of 137 knots. Altitude is 500 feet. Instructor pilot realises plane is too low.

16 seconds: Speed falls to 118 knots, altitude now 200 feet. Pilots notice plane not centred to runway and try to correct. Indicator lights near runway show plane is pointed too low.

8 seconds: Speed falls to 112 knots, altitude 125 feet. Plane's throttles start moving forward.

7 seconds: Crew member is heard on cockpit voice recorder calling for more speed.

4 seconds: Sound of "stick shaker" is heard warning of a stall.

3 seconds: Flight reaches lowest speed of 103 knots. Engines at half power and power increasing. Engine response to command to increase power appears to be normal.

1.5 seconds: Call is made to abort landing and "go-around."

Impact: Speed is 106 knots. Plane's tail section hits sea wall at edge of runway reaching into San Francisco Bay and breaks off. Debris is strewn along runway as plane comes halt.