Southwest Airlines is working with the FAA to investigate the close call|Acroterion|CC BY-SA 4.0

A Southwest Airlines flight dropped 475 feet when flying midair to avoid colliding with a Hawker Hunter aircraft on Friday. Two flight attendants are being treated for injuries from the incident.

The Southwest plane took off from Burbank to Las Vegas and was 14,100 feet in the air when it did the free fall. It landed safely at the destination.

Passengers say the pilot announced the maneuver was necessary to “avoid a midair collision.”

At their closest point, the two aircraft were 4.86 miles apart. The Hawker Hunter fighter jet was flying from Texas to California.

Southwest is now working with the FAA to investigate the close call.