Two investigators from the National Transportation Safety Board were already at work Friday to look into the fire that appeared after American Airlines flight 1006 arrived in Denver the evening before.

A diverted American Airlines plane caught fire on the tarmac after making an emergency landing at Denver International Airport with engine issues Thursday evening, forcing passengers to evacuate the burning aircraft, authorities said.

An American Airlines plane engine caught fire at Denver International Airport after the aircraft was diverted there Thursday evening, officials said, forcing passengers to deplane onto the aircraft’s wing as smoke enveloped the plane.