What happened
On the day of the accident, American Eagle Flight 4184 was scheduled to depart Indianapolis at 14:10, but experienced a delay due to weather-related traffic changes at Chicago-O'Hare. The turboprop aircraft departed the gate at 14:14 and was held on the ground for 42 minutes before receiving takeoff clearance at 14:55. During the flight, the aircraft climbed to 16,300 feet and later began a descent to 10,000 feet at 15:13. During this descent, the Level III airframe de-icing system was activated twice.
At 15:18, the crew was instructed to enter a holding pattern near the LUCIT intersection. Following a descent instruction to 8,000 feet at 15:56, the aircraft's engine power was reduced to flight idle. At 15:57:21, while descending at 186 KIAS with a 15-degree right-wing-down attitude, a flap overspeed warning was recorded. As the crew retracted the flaps to zero degrees, the aircraft experienced a sudden increase in angle of attack and aileron deflection.
The aircraft entered a violent series of rolls. The autopilot disconnected as the plane rolled rapidly to the right, eventually reaching a 77-degree right-wing-down attitude before rolling back toward wings-level. The aircraft then performed a full roll, passing through an inverted position of 180 degrees, with the crew applying significant nose-up control column force. During the subsequent recovery attempt, the airspeed increased to 300 KIAS and the altitude dropped through 4,900 feet. The final recorded data from the flight data recorder showed the aircraft descending at 375 KIAS with a 38-degree nose-down pitch and high vertical acceleration. The aircraft subsequently impacted a wet soybean field in a nose-down, left-wing-low, and partially inverted attitude.
Findings
- The aircraft experienced repeated activation of the Level III airframe de-icing system during descent.
- The flight ended with a high-speed impact following extreme roll and pitch excursions.