15 years ago : same causes, same effects...
On October 31, 1994, Eagle flight 184 from Indianapolis to Chicago-O'Hare, an ATR 72 operated by Simmons Airlines, crashed-during a rapid descent in severe icing conditions after an uncommanded roll excursion. The airplane was destroyed by impact forces; the captain, first officer, 2 flight attendants and 64 passengers received fatal injuries.
The National Transportation Safety Board has determined that the probable cause of this accident was the loss of control, attributed to a sudden and unexpected aileron hinge moment reversal that occurred after a ridge of ice accreted beyond the deice boots because :
1) /…/
2) The French Directorate General for Civil Aviation's (DGAC's) inadequate oversight of the ATR 42 and 72, and its failure to take the necessary corrective action to ensure continued airworthiness in icing conditions;
3) The DGAC's failure to provide the Federal Aviation Administration (FAA) with timely airworthiness information developed from previous ATR incidents and accidents in icing conditions, as specified under the Bilateral Airworthiness Agreement and Annex 8 of the International Civil Aviation Organization.
The Safety Board concludes that no airplane should be authorized or certified for flight into icing conditions more severe than those to which the airplane was subjected in certification testing unless the manufacturer can otherwise demonstrate the safety of flight in such conditions.
As a result of its investigation of this accident, the National Transportation Safety Board recommends that the Federal Aviation Administration :
“Revise the icing certification testing regulation to ensure that airplanes are properly tested for all conditions in which they are authorized to operate, or are otherwise shown to be capable of safe flight into such conditions. If safe operations cannot be demonstrated by the manufacturer, operational limitations should be imposed to prohibit flight in such conditions and flightcrews should be provided with the means to positively determine when they are in icing conditions that exceed the limits for aircraft certification. (Class II, Priority Action) (A-96-56)”
After reading that NTSB safety recommendation, we can expect the French BEA also recommends in the AF 447 report : “Airplanes equipped with Pitot probes must not fly through ice crystal areas”