WPR24LA082 · Piper PA-18A 150

The pilot and passenger departed on a scenic flight in northern Oregon. At an undetermined point in the 3-hr-and-36-minute flight they landed at the passenger’s airstrip. It is unknown how much time they spent on the ground, as the occupants could not recall any details from the accident flight. The passenger reported that they were returning from his property when they impacted the ground. The airplane crashed in mountainous terrain about 40 nautical miles (nm) north of the departure airport. Postaccident examination of the airplane revealed no preimpact mechanical anomalies that could have precluded normal operation. The propeller signatures indicated that the engine was under low power or may have been windmilling at the time of impact. It is unknown if the propeller signatures were due to a loss of power or if the pilot manipulated the throttle control before impact. About 2 gallons of fuel were drained from the right fuel tank and about 7 gallons were drained from the left tank after the accident. It is unknown which tank was selected at the time of the accident, as the fuel selector was in the OFF position at the accident site. The fuel tanks were not breached nor did the fuel system show any evidence of an obstruction. Further evidence suggests that the airplane was also operating in conditions conducive to potentially serious carburetor ice at cruise power; however, it is unknown if the pilot used carburetor heat during the flight. The investigation was unable to determine why the airplane impacted the terrain.

Verbatim NTSB analysis and probable cause from the NTSB dataset