The private pilot reported that, after a preflight inspection and engine run-up revealed no anomalies, he and a passenger departed, circled a nearby mountain, then descended to an altitude about 750′ above ground level.
Shortly thereafter, the Piper PA-22’s engine experienced a partial loss of power. The pilot attempted to restore engine power, but was unsuccessful, and he elected to land the airplane on a dry wash near Fountain Hills, Arizona.
As the airplane touched down, the right main landing gear sank into the dirt, and the airplane made a sharp turn to the right. It hit a tree and came to rest nose down.
The atmospheric conditions at the time of the accident were not conducive to the formation of carburetor icing.
A post-accident engine examination and test run revealed no anomalies that would have precluded normal operation. Therefore, the reason for the loss of partial engine power could not be determined.
Probable cause: A partial loss of engine power for reasons that could not be determined.
NTSB Identification: WPR16LA079
This March 2016 accident report is provided by the National Transportation Safety Board. Published as an educational tool, it is intended to help pilots learn from the misfortunes of others.
The pilot might have advanced the throttle too fast causing the engine to stumble. If I remember correctly, from idle to full throttle minimum 3 seconds. Not sure what it would do from a partial power situation.