Over the Atlantic, west of the Canary Islands, two passenger planes ended up on a head-on course at the same altitude, Bild reports. The incident occurred on July 10, but it has only now become known: an Iberia Airbus A321 was flying from Recife, Brazil, to Madrid, while an Air Europa Boeing 787 was flying from Madrid to São Paulo. Both were at an altitude of about 11,000 meters.

At one point, the TCAS collision avoidance system was activated in the cockpits. It instructed the Iberia crew to descend and the Air Europa pilots to climb. The Airbus descended by about 150 meters, and the Boeing climbed by about 120 meters, after which the danger of a collision passed. Both planes continued their flights and landed normally in Madrid and São Paulo.

Spain’s CIAIAC commission has launched an investigation. It will have to determine how the two airliners could have ended up on the same airway, at the same altitude, and on head-on courses at the same time.