What happened
On the evening of October 31, 1994, American Eagle Flight 4184, operating under the Simmons Airlines brand, departed Indianapolis International Airport bound for Chicago-O'Hare International Airport. The aircraft involved was an ATR 72 turboprop. Shortly after takeoff, while climbing through approximately 10,000 feet, the flight encountered severe icing conditions that were not adequately addressed by the crew or the aircraft's de-icing systems.
The accumulation of ice on the wings disrupted airflow, causing a sudden loss of lift and control. The aircraft entered an unrecoverable spin and crashed into a cornfield near Roselawn, Indiana. The impact was catastrophic, resulting in the immediate death of all 68 people aboard, including passengers and crew members.
Investigation
The National Transportation Safety Board (NTSB) conducted a thorough investigation into the accident. Key findings highlighted that the aircraft's ice protection system was insufficient for the severity of the icing conditions encountered. Additionally, the crew failed to recognize the onset of icing in time to take effective corrective action. The investigation also noted issues with air traffic control communication and weather reporting protocols at the time.
Findings
The primary contributing factor to the accident was the failure of the aircraft's ice protection system to prevent ice accumulation on critical surfaces. This led to a loss of control that could not be recovered from. The NSB concluded that better crew training for icing conditions and improved ice detection technology were necessary to prevent similar incidents in the future.