Piper PA 28 N8223W accident near Sacramento, California

Probable cause

A partial loss of engine power during initial climb for reasons that could not be determined because postaccident examination revealed no evidence of preimpact mechanical malfunction or failure that would have precluded normal operation.

NTSB analysis

The pilot was receiving a checkout in the airplane from a flight instructor. This was their second flight together in the airplane, and the pilot's second flight in that airplane make and model. According to the pilot and the instructor, the preflight inspection detected no anomalies, and the airplane had sufficient fuel for the flight. Engine start, taxi, and engine run-up were all normal. According to the pilot, during the climbout, when the airplane was about 500 feet above the ground, the engine "sputtered," recovered briefly, and then "lost thrust." The flight instructor reported that the engine was running "roughly." The pilots briefly attempted to restore power. Their efforts, which included changing the position of the fuel selector handle, were unsuccessful; they then attempted to land in a clearing on a golf course adjacent to the airport. The airplane struck trees and came to rest inverted on the golf course. Postaccident examination of the airframe and engine confirmed that the engine was developing little or no power at impact but did not reveal any preimpact conditions or failures that would have precluded continued engine operation.

Before the takeoff, the engine was idled on the ground for at least 8 minutes. Although the carburetor heat was off (the recovered checklist did not reference carburetor heat) and the ambient conditions were conducive to "serious icing" at glide power, both pilots reported that the taxi, engine run-up, and takeoff roll were normal. Thus, it is unlikely that carburetor ice was present at the time the engine began to lose power.

The airplane's original fuel selector handle and placard design were ambiguous with regard to the selection indication, particularly to a person unfamiliar with the airplane; the selector could inadvertently and unknowingly be set to the "OFF" position for flight. The manufacturer issued two service letters (in 1971 and 1972), which recommended modification of the fuel selector, and subsequently issued a mandatory service bulletin (in 1986) that called for the replacement of the handle and placard to reduce the possibility of pilots inadvertently selecting the "OFF" position for flight. Although the service bulletin was applicable to the accident airplane, the handle and placard had not been replaced.

Because the pilot manipulated the fuel selector following the power loss and a first responder manipulated it after the accident, neither the takeoff nor the preimpact setting of the fuel selector valve could be determined. The investigation was unable to determine if the fuel selector valve was inadvertently set to the "OFF" position at some point before the takeoff, allowing some limited high-power engine operation using residual fuel. The investigation also considered the possibility that the fuel selector valve was improperly set so that the selector valve ports were partially, instead of fully, aligned, allowing sufficient fuel for low-power operation and limited-time high-power operation. However, because power was not restored after the pilot repositioned the fuel selector after the first indication of an engine problem, it is unlikely that a mis-set fuel selector valve caused the power loss.

Text from the NTSB. Open the NTSB docket for WPR13LA384 for the full record.