Date: February 17, 1991
Type: Douglas DC-9-15
Registration: N565PC
Operator: Ryan International Airlines
Where: Cleveland-Hopkins International Airport, Cleveland, Ohio
Report No. NTSB/AAR-91/09
Report Date: November 16, 1991
Pages: 100

[This is the Executive Summary, not the Abstract.  New format.]

About 0019, Sunday, February, 1991, Ryan International Airlines flight
590 (Ryan 590), a DC-9 series 10 airplane, crashed while taking off
>From Cleveland-Hopkins International Airport.  The flightcrew consisted
of two pilots.  There were no other crewmembers or passengers on the
flight, which was contracted to carry mail for the U.S. Postal
Service.  Both pilots were fatally injured, and the airplane was
destroyed as a result of the accident.

The National Transportation Safety Board determines that the probable
cause of this accident was the failure of the flightcrew to detect and
remove ice contamination on the airplane's wings, which was largely a
result of a lack of appropriate response by the Federal Aviation
Administration, Douglas Aircraft Company, and Ryan International
Airlines to the known critical effect that a minute amount of
contamination has on the stall characteristics of the DC-9 series 10
airplane.  The ice contamination led to wing stall and loss of control
during the attempted takeoff.

The safety issues discussed in this report include the dissemination of
information regarding precautions to be taken when operating in
conditions conducive to airframe ice and the particular susceptibility
of DC-9 series 10 airplanes to control problems during take off with
a minute amount of ice is on the wing.