Two passengers taken to hospital with injuries on United flight after pilots responded to collision call

() – The Federal Aviation Administration has opened an investigation into a shakeup of a United Airlines flight that injured two passengers when pilots responded to a crash system warning mid-flight.

United Airlines says that as Flight 2428 from Newark, New Jersey, descended toward San Francisco International Airport last Thursday, it “slowed its descent to account for the presence of another aircraft at a lower altitude.” The two injured passengers were taken to the hospital, United said in a statement.

An FAA incident report says one passenger received serious injuries and another received minor injuries last Thursday when pilots responded to a traffic collision avoidance system, or “TCAS RA,” advisory.

Collision resolution warnings are treated as extreme warnings of a possible collision with another aircraft and pilots are required to act immediately.

Data from FlightRadar24 shows that the incident took place at 9,500 meters when the flight was near Lake Berryessa, about 70 kilometers north of San Francisco. FlightRadar24 says a Southwest Airlines flight was 900 meters below the United flight and a SkyWest flight was 300 meters below.

In a statement, the FAA – responsible for air traffic control – said that “there was no loss of safe separation.”

LiveATC.net audio captured the pilots declaring a medical emergency, telling air traffic controllers in Oakland that “someone might have broken an ankle and there are passengers who were injured when we had an AR.”

United Airlines told that the seat belt sign was on at the time of the incident 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 spokesperson told that the agency is gathering preliminary information.

Thursday’s in-flight incident is the latest related to a possible near-collision this month. On September 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 as both planes were taxiing, causing the tail of the regional jet to detach.