Investigators say the plane's wing flaps were wrongly deployed
A Spanish passenger jet crashed in August because the wing flaps were in the wrong position, investigators say.
A warning system failed to alert the pilots and the Spanair flight 5022 crashed on take-off at Madrid's airport, killing 154 people on board.
The MD-82 plane reached an altitude of just 12m (40ft) before crashing to the ground and bursting into flames.
The investigators' preliminary report does not apportion blame, saying that the pilots carried out routine checks.
Eighteen people survived the crash, Western Europe's worst air disaster in two decades.
The investigators, who studied voice and flight data recorders, found no evidence of prior engine problems and concluded that the plane had caught fire only after hitting the ground.
It is unclear why the wing flaps failed to deploy, but the error was compounded by the failure of the cockpit alert system, which should have sounded a warning to the pilots.
A judge will now decide whether anyone can be held criminally responsible.