That’s the conclusion of a preliminary report from the Spanish Civil Aviation Accidents and Incidents Investigation Commission.
According to the document, this “serious” incident took place on October 2, when a Boeing 737-800 plane traveling from Santiago to Palma de Mallorca, and another identical aircraft heading from Seville to Toulouse, came dangerously close to one another around 30 kilometers from Pamplona.
The planes were “on the frequency of the Madrid control center” when the anti-collision alert systems on both planes sounded.
According to the commission, the planes were around four kilometers apart horizontally, and just 122 meters apart vertically. Once the alarms had sounded, the flight crew corrected their courses and the flights continued without incident.