(CNN) – The Federal Aviation Administration has opened an investigation into a United Airlines plane turbulence that injured two passengers when pilots responded to a mid-flight collision system warning.
United Airlines says that when Flight 2428 landed from Newark, New Jersey, to San Francisco International Airport last Thursday, it “slowed its descent to accommodate another aircraft at a lower altitude.” The two injured passengers were taken to the hospital, United said in a statement.
One passenger was seriously injured and another suffered minor injuries last Thursday when pilots responded to a traffic collision avoidance system, or TCAS RA, advisory, the FAA incident report says.
Collision Resolution Warnings are treated as severe warnings of a potential collision with another aircraft and pilots must act immediately.
FlightRadar24 data shows the crash occurred at 30,000 feet (9,500 meters) as the flight near Lake Berryessa, about 43 miles (70 kilometers) north of San Francisco. FlightRadar24 says a Southwest Airlines flight was 3,000 feet (900 meters) below the United flight and a SkyWest flight was 1,000 feet (300 meters) below.
“There was no loss of safe separation,” the Federal Aviation Administration, which is responsible for air traffic control, said in a statement.
LiveATC.net captured the pilots announcing a medical emergency, telling air traffic controllers in Oakland: “Someone may have broken their ankle, there were passengers who were injured when we had the AR.”
United Airlines told CNN that a seatbelt sign was in place at the time of the crash, and that one of the injured passengers was out of his seat.
The National Transportation Safety Board has not yet opened an investigation, but a spokesman told CNN the agency is gathering preliminary information.
Thursday’s incident on the plane is the latest involving a potential collision this month. On Sept. 12, an Alaska Airlines flight had to abort takeoff in Nashville because a Southwest flight was crossing the same runway. Two days earlier, the wingtip of a Delta Air Lines Airbus A350 collided with a smaller regional jet while the two aircraft were in motion, causing the regional jet’s tail to separate.
