Gillespie Field Airport
Aircraft Accident/Incident Report

Warner Springs, California 90224
Monday, October 17, 2005 10:38 PDT

The single engine airplane collided with mountainous terrain at the 6,111-foot level while maneuvering below an overcast cloud layer. Meteorological conditions over the area consisted of overcast cloud bases between 6,000 and 7,000 feet mean sea level (msl), and a patchy broken cloud layer with bases around 2,000 to 3,000 feet msl. Cloud tops were between 7,000 and 10,000 feet msl, and the freezing level was at 10,000 feet msl. Light to moderate rime or mixed icing was likely in clouds above the freezing level. Terrain ridgelines above 6,000 feet were occasionally obscured in the vicinity of the accident location, and occasional moderate turbulence was present. The airplane was not certified for flight into known icing. The airplane was equipped with a global positioning system (GPS) that was tied into a moving map cockpit display, which included terrain features and obstacles. The onboard avionics had received via a real time data downlink the latest weather radar images, station meteorological reports, and flight route data. The airplane's onboard GPS track data history and the Federal Aviation Administration (FAA) recorded radar data tracked the airplane from its departure, following a northeasterly track and cruising at altitudes between 5,000 and 6,500 feet msl for about 40 miles. The airplane then made a gradual descent from 6,500 feet to about 6,000 feet msl, and entered a shallow turn to the east where the track ends at the accident site on the south slope of a 6,150-foot mountain. The easterly turn was consistent with a turn towards the first en route waypoint that was delivered by the datalink. The initial point of impact on the mountain slope was the left wing tip at the 6,111-foot level causing the airplane to tumble and breakup over a distance of 501 feet along the mountain ridgeline. Analysis of the impact ground scars and the track history data disclosed the airplane was in level controlled flight when the terrain collision occurred. The airplane's owner, a non instrument rated private pilot, was in the left seat. The right seat occupant held airline transport pilot and certified flight instructor certificates.

The flight crew's failure to maintain adequate terrain clearance and their decision to continue flight into known adverse weather conditions. Contributing to the accident was overcast conditions, and terrain obscuration. A finding of the investigation is that the flight crew may have improperly used the navigation equipment, which had a graphical moving map display capability, to guide the airplane between clouds and mountainous terrain while in obscured visibility conditions.