Synopsis
American Eagle flight 4184 was a flight flying from Indianapolis, Indiana to Chicago on October 31, 1994. The aircraft was an ATR 72 with 64 passengers and 4 crew.
Bad weather in Chicago caused delays, prompting air traffic control to hold Flight 4184 over an intersection at 10,000 ft. After holding for about 35 minutes, the pilots were cleared to descend down to 8,000 ft and enter another hold. While descending, the pilots heard a flap-over speed warning. The pilots responded by retracting flaps, which caused a momentary increase in angle of attack,followed by the disengagement of auto-pilot and an uncontrollable steep descending roll excursion. Less than two minutes after this event, the plane crashed into a field in Roselawn, Indiana.
Causes of the crash
Icing has been attributed to be the main cause of the crash. The flight's holding pattern took it through various layers of cloud, which exposed the plane to icing conditions. The plane was operating its icing envelope and the ATR's de-icing boot could not remove all the ice effectively, especially runback ice.
The flight crew took the necessary actions to deal with ice build-up on the plane. However, as they retracted their flaps, the autopilot increased pitch attitude to maintain preset vertical speed of descent. As the nose pitched up, the icing on the plane led to a wing-drop stall. The force of the turbulence on the plane's wings caused the plane to roll to the right and the pilots were unable to recover.
**The following videos give a detailed explanation of the accident. **
(Source- Air crash investigation TV series season 6 episode 8)
Part 1 of 5
Video embedded from YouTube on 24 September 2009
Part 2 of 5
Video embedded from YouTube on 24 September 2009
Part 3 of 5
Video embedded from YouTube on 24 September 2009
Part 4 of 5
Video embedded from YouTube on 24 September 2009
Part 5 of 5
Video embedded from YouTube on 24 September 2009