Source: Simon Hradecky | www.avherald.com

An Envoy Embraer ERJ-145, registration N664MS performing flight AA-4474 from Little Rock,AR to Chicago O’Hare,IL (USA) with 50 passengers and 3 crew, was enroute at FL250 about 80nm southsouthwest of St. Louis,MO (USA) when the crew donned their oxygen masks, reported a fire indication and decided to divert to St. Louis requesting runway 12R. During the approach the crew advised they had used their fire bottles, however, the indication didn’t stop. The aircraft positioned for an approach to runway 06 and landed safely on runway 06 about 18 minutes after leaving FL250. The crew queried tower whether any smoke was visible from their tail, the tower reported seeing no smoke from their tail whatsoever.

St. Louis Tower told emergency services initially they had used their fire bottles and subsequently followed up the captain had just indicated there was an actual fire in the cabin and relocated the emergency services to the end of runway 06 advising the aircraft was coming in as fast as they could.

A replacement ERJ-145 registration N696AE reached Chicago with a delay of about 4 hours.

The occurrence aircraft is still on the ground in St. Louis about 24 hours after landing.

Later The Aviation Herald received information the #2 Air Cycle Machine had seized causing smoke in the cabin.