An NTSB Advisory about the incident says:
Post-flight inspection of the airplane revealed an in-flight deployment of the aft emergency exit slide within the tail cone.Thank goodness the tail cone did not separate, but you have to admit, this was a very strange incident. I don't believe I've ever heard of an emergency slide spontaneously deploying inside a tail cone. If any readers know of a similar incident, please let me know.
Preliminary information indicate that the crew disconnected the autopilot during climbout from Chicago, while being vectored around thunderstorms, when they reportedly felt elevator control forces that were heavier than normal. They therefore elected to make a precautionary landing at St. Louis. After landing, it was learned that the aft emergency exit slide had deployed within the tail cone. The tail cone did not separate from the airplane.
For what it's worth, a source tells me that this particular aircraft (N804ME) is the oldest in the Midwest Airlines fleet, although this information has not been independently confirmed.
Here is an Associated Press video interview with Sen. Obama about the incident:
(If the video does not play or display properly above, click here to view it on YouTube.)