NTSB Identification: CEN09FA340
14 CFR Part 91: General Aviation
Accident occurred Sunday, June 07, 2009 in Humbird, WI
Probable Cause Approval Date: 07/18/2011
Aircraft: Gulfstream American Corp AA-5B, registration: N448DM
Injuries: 2 Fatal.
NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
The non-instrument-rated private pilot obtained two weather briefings before departing on the visual flight rules (VFR) cross-country flight. During the weather briefings he was advised that VFR flight was not recommended because of an active weather advisory for widespread instrument meteorological conditions that encompassed his planned route. The weather advisory was for occasional cloud ceilings below 1,000 feet above ground level (agl) and surface visibilities less than 3 miles with light precipitation/mist. The forecast weather was for ceilings 1,500 to 2,500 feet agl with widely scattered light rain showers and isolated thunderstorms. Approximately 1 hour after departure, several witnesses located near the accident site reported hearing an airplane overfly their position. These witnesses noted that because of a low cloud ceiling, fog, and light precipitation they could not see the airplane. The witnesses reported hearing the sound of an airplane engine operating at a high speed. Several witnesses noted that the loudness of the airplane's engine increased and decreased several times, as if the airplane was turning, before they heard a ground impact. The distribution of the wreckage was consistent with an airplane that experienced a loss of control and an in-flight breakup at low altitude and high airspeed. The challenging visibility conditions were conducive to the onset of pilot spatial disorientation and the airplane's rapid, near-vertical descent is consistent with the pilot's loss of control of the airplane because of spatial disorientation. The postaccident investigation revealed no preexisting mechanical malfunctions or anomalies that would have prevented the normal operation of the airplane or its systems.
The National Transportation Safety Board determines the probable cause(s) of this accident to be: The pilot's decision to attempt a visual flight rules flight into an area of known instrument meteorological conditions, which resulted in a loss of control due to spatial disorientation. Full narrative available
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