WPR23FA172 · Cessna 172S

The non-instrument-rated private pilot rented the airplane from a flight school, where he had just completed a flight review two days before the accident. The flight was for pleasure, with the pilot planning to have lunch in the area and return later in the day. Marine layer weather conditions consisting of low visibilities and low ceiling had been forecast and were being reported at his destination and in the area of the accident around the time the airplane took off from the departure airport for the return flight. Phone records indicate that the pilot checked the weather about the time of departure and would have been aware that his destination airport was already reporting instrument meteorological conditions, and that he would not have been able to land there. Nevertheless, he continued with the departure, taking off about 50 minutes before sunset. All inland airports along the pilot’s route of flight were reporting VFR weather conditions.

For the first segment of the flight the airplane flew along a reciprocal route to the outbound journey. The pilot then began a gradual descent, likely in preparation for landing. About an hour after takeoff, the flight reached the congested airspace at the southeastern edge of the Burbank Airport (BUR) Class C airspace and the border of the LAX Class B airspace. By now the sun had set, and the area to the pilot’s left (south) was completely enveloped in clouds. Clouds were likely also intermittently obscuring the surrounding terrain, lighting, and ground features as the marine layer progressed. However, Van Nuys Airport, just 10 miles northwest, was reporting clear skies and unlimited visibility.

After descending to about 1,000 ft agl over the Hollywood Hills, the pilot initiated contact with the Van Nuys control tower. He was provided a transponder code and began a series of communications with the tower controller, who gave him instructions to turn toward a highway interchange reference point just south of the airport. He did not appear to understand the reference, so the controller provided him with a northwest heading and the airplane began to turn northwest, toward the airport, while descending.

The airplane continued to descend with no further communication from the pilot; a short time later it struck the top of a hilly peak, about 8 miles short of the landing runway. The debris field direction, length, and pattern indicated the airplane was flying straight and level, at a high speed; the airplane impacted in a manner consistent with controlled flight into terrain.

During the final segment of the flight the airplane descended so low that it is likely the pilot could no longer distinguish between the lights of the hillside residences and the lights in the valley beyond and ahead where the airport was located. Compounding the visual illusion would have been the rising terrain beyond the airport, the low clouds that were forming in the area, the decreasing light levels, and the fact that the area the airplane struck was unlit and probably not visible to him. He was therefore likely experiencing a visual illusion as he flew toward the airport and lost situational awareness. The weather then deteriorated so rapidly that it hampered the search efforts, even though it was in a densely populated area.

The pilot had relatively low time, and did not hold an instrument rating. He learned to fly in another city, and although he had flown in the Los Angeles area about half a dozen times before, those journeys were during daylight hours and avoided most of the congested airspace close to the accident area. It is therefore likely that he was task saturated as he approached the airport through unfamiliar and busy terrain and airspace, and his communication with the control tower appeared to indicate he was slightly confused.

Examination of the airframe and engine did not reveal any anomalies that would have precluded normal operation, and damage signatures indicated the engine was producing power at impact.

The pilot had Type I diabetes mellitus and was using insulin. However, his diabetes was well managed with medication and was therefore not a factor in the accident.

Verbatim NTSB analysis and probable cause from the NTSB dataset