Spanish investigators believe the driver of a vehicle lost situational awareness before heading along an active Madrid runway while an Airbus A330 was departing from the opposite direction.
The Air Europa A330-200, heading for Santa Cruz in Bolivia with 279 occupants, had been cleared for take-off on runway 36L.
Spanish investigation authority CIAIAC says the take-off commenced in darkness at around 01:33 local time on 17 October 2014.
The vehicle was supposed to be heading for the parallel runway 18L-36R, via a perimeter road, but its driver told the inquiry that he had been "distracted" and was "convinced" he was entering the correct runway.
It entered runway 36L approximately at its midpoint, and initially turned north, travelling 800m along the runway. It was still heading north – although its precise position could not be determined – as the A330 began to roll.
CIAIAC says the jet was some 55m into its roll when the vehicle, around 2,700m from the runway 36L threshold, turned around and began to head south, towards the aircraft.
Some 560m into its take-off roll the A330's crew "noticed the presence of a light different from those of the runway indicators", says the inquiry, and contacted the Madrid Barajas tower for clarification. The tower could not identify the anomaly.
The aircraft subsequently passed the vehicle 46s after commencing take-off. CIAIAC says the vehicle, at this point, had been parked at the side of the runway about 1,875m from the threshold.
CIAIAC says the aircraft became airborne without incident and the vehicle left the runway without reporting the event. The inquiry found the vehicle did not have a transponder and did not have its anti-collision light on.
It adds that the driver failed to pay enough attention and lost situational awareness, adding that the company responsible for the vehicle lacked adequate training and did not sufficiently promote a culture of safety.