German investigators have disclosed that the Lufthansa Cargo Boeing MD-11 freighter which crashed and burned on landing in Riyadh made three heavy contacts with the runway.
It hit runway 33L with a vertical impact of about 2g, says the German investigation agency BFU, before lifting off again.
This was followed by a second contact of 3g and another at 4.3g before the tail structure behind the main landing-gear failed.
The MD-11F veered off the left side of the runway about 2,400m (7,900ft) after the initial touchdown and careered for a further 375m in the sand before coming to a halt.
Two pilots were the only occupants of the tri-jet. One of them was seriously injured, the other only lightly.
Lufthansa Cargo's flight LH8460 had been arriving after a flight from Frankfurt, with 80t of cargo on board, when the accident occurred on 27 July.