American Eagle Flight 4184Monday October 31, 1994
The aircraft was in a holding pattern and was descending to a newly assigned altitude of 8,000 feet when it experienced an uncommanded roll and excursion and crashed during a rapid descent. Icing. The design of the rubber de-icing boot was insufficient to deal with icing on the wings. Sudden and unexpected aileron hinge movement reversal, that occurred after a ridge of ice accreted beyond the deice boots while the airplane was in a holding pattern during which it intermittently encountered supercooled cloud and drizzle/rain drops, the size and water content of which exceeded those described in the icing certificication envelope. The airplane was susceptible to this loss of control and the crew was unable to recover. Contributing factor was the French Directorate General for Civil Aviation's inadequate oversight of the ATR42 and ATR 72, and its failure to take the necessary corrective action to ensure continued airworthiness in icing conditions and failure to provide the FAA with timely airworthiness information developed from previous ATR incidents and accidents in icing conditions.