Event Summary
During a scheduled landing approach to Washington Dulles International Airport (IAD), the aircraft descended through a cloud layer. The crew reported that trace rime ice accumulated on the wing surfaces. Although pitot and stall avoidance system (SAS) heat were used, the captain elected not to activate engine inlet anti-ice.
Shortly after passing the outer marker, the left engine lost power, followed by the right engine. The captain managed to set the aircraft down in an open field. During the landing roll, the landing gear collapsed.
Post-Accident Inspection
Following the event, the engines were successfully run up at a Garrett facility. Ice was found beneath the right wing that matched the curvature of the wing's leading edge. Additionally, a round conical piece of ice was discovered along the wreckage path, matching the nose of the propeller spinner.
Flight Manual Guidance
The flight manual contained a warning and a note stating that engine heat and continuous ignition must be used after leaving icing conditions until the pilot is confident that any significant residual ice will not be ingested into the engines.
Probable Cause
The official probable cause findings identified: (1) loss of engine power (total) due to weather conditions (icing), the pilot in command's improper in-flight planning/decision and failure to use anti-ice/deice system, inadequate initial training by the check pilot, and inadequate certification/approval by the company/operator management; (2) gear collapsed due to terrain conditions (open field, downhill) and dark night lighting.