Following a pilot’s incapacitation and subsequent death on Saturday night, an Envoy Air flight returned to Chicago shortly after takeoff, the airline said Tuesday.

The regional airline Envoy Air, which is owned by American Airlines, said in a statement that “our colleague passed away at the hospital despite heroic efforts by those on board and first responders on the ground.” We are extremely saddened and are currently doing everything we can to support his family and our coworkers.
The pilot was a captain-in-training, according to Capt. Ric Wilson, vice president of Envoy’s flight operations, in a note to staff.

Regarding what precipitated the medical emergency, Envoy made no comments. The union for Envoy’s pilots, the Air Line Pilots Association, declined to comment.

FlightRadar24 reports that American Airlines parent company Envoy Air Flight 3556, an Embraer E175 operating for American Airlines’ American Eagle, arrived back at Chicago O’Hare International Airport at 7:57 p.m. local time, 37 minutes after taking off for Columbus, Ohio.
According to ATCLive, which has an archive on its website, a recording of messages to air traffic controllers shows “captain is disabled.” The individual on the video, who appeared to be another pilot on the flight, added, “We’re going to require paramedics.” A minimum of two pilots are required to crew commercial jetliners.

Such incidents, according to a spokeswoman for the Federal Aviation Administration, are uncommon but that the agency is looking into it.