Narrative:

After reaching cruising altitude; about thirty minutes into the flight; I noticed that the captain's behavior had changed. He became incoherent and unresponsive to questions. I then noticed that he began to make fists with both hands; shake; and bite his tongue. I continued to ask him if was okay. After I received no response I alerted the flight attendant to a possible seizure with the captain and asked her if she would help with assessing the situation while I flew the plane. I then declared an emergency with center and requested to land at the nearest airport. We landed 2;000lbs overweight due to the emergency and the unscheduled landing. The captain remained non-responsive and in the same condition throughout the decent and landing. Once on the ground; I brought the aircraft to a stop on the runway and shut down the engines. Emergency crews met the aircraft and removed the captain to an awaiting ambulance. At this time the only conclusion I can come to is that the captain has continued issues with diabetes. This was not known by the rest of the flight crew. From updates received while waiting for a replacement captain; we were informed he had suffered from issues related to his disease. A stronger review of medical issues that an individual has must be addressed in this type of event. We cannot allow a person who has continued medical problems to fly until they are proven to be healthy and fit for flight.

Google
 

Original NASA ASRS Text

Title: An Air Carrier First Officer noticed that the Captain was incoherent and unresponsive. He declared an emergency and landed at the nearest airport. Diabetes-related loss of consciousness is suspected to be the cause.

Narrative: After reaching cruising altitude; about thirty minutes into the flight; I noticed that the Captain's behavior had changed. He became incoherent and unresponsive to questions. I then noticed that he began to make fists with both hands; shake; and bite his tongue. I continued to ask him if was okay. After I received no response I alerted the Flight Attendant to a possible seizure with the Captain and asked her if she would help with assessing the situation while I flew the plane. I then declared an emergency with Center and requested to land at the nearest airport. We landed 2;000lbs overweight due to the emergency and the unscheduled landing. The Captain remained non-responsive and in the same condition throughout the decent and landing. Once on the ground; I brought the aircraft to a stop on the runway and shut down the engines. Emergency crews met the aircraft and removed the Captain to an awaiting ambulance. At this time the only conclusion I can come to is that the Captain has continued issues with diabetes. This was not known by the rest of the flight crew. From updates received while waiting for a replacement Captain; we were informed he had suffered from issues related to his disease. A stronger review of medical issues that an individual has must be addressed in this type of event. We cannot allow a person who has continued medical problems to fly until they are proven to be healthy and fit for flight.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.