NTSB: 21 Air 767 crossed Miami runway threshold at twice normal height

US investigators have released preliminary details of the 6 September accident at Miami in which a 21 Air Boeing 767-300 freighter overran the runway and struck a van on the perimeter road, fatally injuring people in the vehicle.

According to the National Transportation Safety Board, the aircraft passed over the threshold of runway 30 at roughly 105ft, about double the height normally expected at that point. It touched down 3,750ft beyond the threshold.

Runway 30 measures 9,360ft, but that figure includes a threshold displaced by 945ft, so the landing occurred near the midpoint of the available surface. The jet registered a groundspeed of 160kt at touchdown, 13 seconds after crossing the threshold.

The aircraft did not settle immediately. The weight-on-wheels sensor alternated between "air" and "ground" for about seven seconds, and by the time it gave a steady ground indication, 2,730ft of runway remained.

Flight-data recorder information showed the speedbrakes stayed stowed, with no movement of the speedbrake handle, and the thrust-reversers were not deployed. The inquiry has not yet determined how the alternating air-ground status affected the aircraft's systems.

Investigators say the wheel brakes were applied by hand at 146kt groundspeed but the pedals were let go eight seconds later, by which time the jet had slowed to 120kt. At that point the thrust levers were moved toward go-around power with 930ft of runway left.

Recorded data indicates the flaps, set to 30° about ten seconds before touchdown, began retracting toward 25°. Four seconds later, at 117kt, the thrust levers came back to idle and the brakes were applied again. Only 415ft of runway remained, and the aircraft left the surface at 113kt.

It struck the localiser and approach lighting at the far end, travelling 1,200ft past the paved surface, and hit a van during that distance.