GULFSTREAM AMERICAN CORP AA-5A — Lakeview, OR

What happened

The pilot dropped off two passengers at an airport where overcast clouds and occasional snow showers were present and then departed for the return flight to the original departure airport. GPS data indicated that during the return flight the airplane crossed mountainous/hilly terrain. When the pilot reached the western edge of the last mountain ridge, he turned and flew in a northerly direction along its steep western slope. The pilot then performed a 180-degree turn, during which the airplane’s groundspeed increased significantly in a short period of time. Just after the pilot rolled out of the turn, the airplane’s groundspeed suddenly decreased below that required to maintain flight, and, almost immediately, the airplane descended into the terrain. A review of weather information indicated that the base of the overcast cloud layer was below the tops of some of the terrain in this area. Snow showers, strong wind, and patches of fog were present beneath the overcast. It is likely that the pilot flew into the adverse weather or was maneuvering around it when the loss of airplane control occurred. Postaccident examination of the airframe and engine revealed no evidence of a mechanical malfunction or failure that would have precluded normal operation.

An editorial "what led to it / how to avoid it" analysis for this accident is generated separately and will appear here.