: 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 public aircraft accident report.
The commercial pilot departed on a fire detection flight for a state fire commission using a predetermined flight route. The pilot was receiving flight-following services from the dispatch center and was reporting his flight progress to a dispatcher. The pilot reported entering the eastern boundary of the forest district and then turning north toward the next checkpoint. Five minutes later, the pilot reported that he was turning back due to low cloud ceilings. About 14 minutes later, the airplane impacted trees on a ridgeline, which had an elevation of 1,473 ft, and the main wreckage was located 0.3 mile south of the ridgeline.
A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Examination of the propeller revealed damage consistent with a medium-to-high power setting at impact. Although the airplane was equipped and certificated for flight in instrument meteorological conditions, the instruments required for instrument flight were not maintained to those standards; therefore, the airplane was limited to flight in visual flight rules conditions only. Surface weather reports indicated low cloud ceilings of 700 to 1,100 ft above ground level along most of the route of flight. Wave clouds and associated turbulence also existed in the area about the time of the accident. A surface weather reporting station located 21 nautical miles west of the accident site and within the planned route of flight was reporting clouds overcast at 500 ft at the time of the accident. The fire commission’s aviation department did not use flight risk assessments. No record was found indicating that the pilot received a preflight weather briefing; however, it could not be determined if the pilot obtained weather information using other sources.Toxicological testing detected nortriptyline, which can be impairing, in the pilot’s liver; however, no evidence was found indicating that the nortriptyline impaired his decision-making or flying skills at or around the time of the accident.