AN investigation has been launched after a shocking near-miss that saw two passenger planes descend for the same runway just meters apart.

The incident was recorded by a man who was out for a walk with his family in Phoenix on the morning of January 11.

A United Airlines flight and a Delta flight appeared to almost collide as they prepared to land at Pheonix Sky Harbor International Airport.

Delta Flight 1070 was coming in from Detroit with 245 passengers on board and was given clearance to land on runway 8.

Just as the pilot confirmed having a clear view of the runway, an alert went off in the cockpit around 11 am saying “Descend descend.”

At the same time, United Flight 1724 arriving from San Franciso with 123 passengers and six crew members also received a collision alert.

Justin Gibbons who was on the ground at the time, told AZ Family about the moment he knew something was wrong.

He said: “I was just watching it make its turn and then all of a sudden I see another plane coming off to the left looking like they’re in an intersecting path.”

The amateur pilot detailed how he went into “immediate panic mode” while filming the terrifying moment.

“It was very very close,” he said.

“It just makes you think oh man they really avoided a major disaster.”

At one point, the two passenger planes were just 425 feet apart, with one above the other, according to data from FlightRadar24.

After both pilots received the collision warning and altered their altitudes, they changed direction and became 1,200 feet apart next to each other.

A former chairman of the National Transport Safety Board told the outlet that these planes should always be at least five miles apart horizontally.

But, as a result of their quick thinking, both planes landed safely.

The Federal Aviation Administration is investigating the incident.

The agency said: “Both flight crews received onboard alerts that the other aircraft was nearby.

“Air traffic control issued corrective instructions to both flight crews.”

CBS News retrieved audio from air traffic control where a controller cleared the United flight for runway 7 and told the Delta flight to line up to land on runway 8.

Both airlines are said to be cooperating with the FAA’s investigation.

Delta said its crews are “extensively trained to handle uncommon scenarios such as this.”

United confirmed its pilots “acted immediately” after receiving the cockpit alert and managed to land safely.