Two passenger planes came too close to colliding in the air near George Bush Intercontinental Airport in Houston, an investigation shows.

The two planes were both taking off when the incident occurred earlier this month. Both planes were United Airbus A-320's which can hold up tp 150 people each. The two planes were heading down separate runways on May 9 when they came just within 400 feet of each other, KHOU reports.

United Flight 601, heading for Vancouver, Canada and United Flight 437, heading for Mexico City, came close to having a disaster upon takeoff and no one on either flight knew about it besides the pilots.

KHOU released an air traffic control recording which documented the incident and how Flight 601 was accidentally sent into the direction of the other flight just after takeoff.

The air traffic controller said, "Flight 601 turn right parallel traffic." However the controller meant turn left. The mistake led Flight 601 right into the path of Flight 437, and just 400 feet below it. The two planes were less than a mile apart and were seconds away from colliding with each other while using high takeoff

Luckily the controller quickly realized the mistake and redirected the planes so they wouldn't hit each other. The pilots were aware that something went wrong.
"Hey, you know what happened there?" one pilot is heard asking another.
"You all basically crossed directly over the top of each other," a second pilot replies.

"That's what it looked like from my perspective. I have no idea what was going on over there in the tower. But, you know, it was pretty gnarly looking," said the first pilot.

The pilot of Flight 601 realized that the air traffic controller had meant turn left instead.

Some sources that the air traffic controller responsible may have been in training. The incident is being investigated.