Piper PA 24-250 N7428P accident near Garberville, California

Probable cause

A loss of engine power for reasons that could not be determined due to extensive damage sustained during the collision and postaccident water immersion.

NTSB analysis

The private pilot was conducting a routine cross-country flight to the destination airport. The pilot had conducted this same flight once a month for the previous 5 years to serve as a community rural doctor. Numerous witnesses reported observing the airplane maneuvering toward the airport at a very low altitude just below the cloud layer. Several witnesses near the accident site stated that they did not hear any engine noise. The airplane impacted a tree about 2,260 ft short of the approach end of the runway and came to rest in a river, partially resting on a gravel/sand embankment. Following the accident, the water level quickly rose, nearly submerging the entire airframe.

Although a postaccident examination revealed no evidence of preimpact mechanical malfunctions or failures, the extent of the damage sustained during the collision and the water immersion precluded a detailed determination of the engine and fuel system preimpact condition, settings, and functionality. One of the three propeller blades was bent aft about 80 degrees near the blade root, but the other two blades were undamaged. Based on this minimal damage and the witnesses' accounts of not hearing engine noise, it is likely that the engine experienced a loss of power while the pilot was on approach to the airport.

Fuel was found in the fuel lines forward of the firewall; therefore, it is unlikely that fuel exhaustion or starvation occurred. The fuel mixture cable was found disconnected from the mixture arm on the carburetor. Given the minimal damage to the mixture arm and that it was not spring-loaded to any position, it is possible that the cable became disconnected in flight and adversely affected the engine operation. However, there was insufficient evidence to determine when the cable became disconnected or whether or when it affected the engine operation.

Text from the NTSB. Open the NTSB docket for WPR15FA045 for the full record.