Cessna 175 N6649E accident near Pine Bluff, Arkansas

Probable cause

A loss of engine power during cruise flight for reasons that could not be determined because a test run of the engine did not reveal any mechanical malfunctions or anomalies that would have precluded normal operation. Contributing to the accident were the tree stumps at the forced landing site.

NTSB analysis

The passenger reported that, about 15 minutes after takeoff on the cross-country flight, the engine began "stalling in and out." Although the pilot attempted to troubleshoot the issue, he could not remedy it, and selected a dirt road as a forced landing site. The passenger stated that the airplane was too fast and too high to land, and the pilot circled the airplane for a second approach. About 150 feet above the ground, the engine experienced a total loss of power. The airplane touched down in an area of tree stumps and immediately nosed over.

Toxicology testing of the pilot revealed the presence of diphenhydramine; however, the level detected was too low to quantify and was unlikely to be impairing. No shoulder harnesses were installed, and their installation was not required. Advisory Circular 91-65, in part, stated, "The [National Transportation Safety Board] concluded that shoulder harness use is the most effective way of reducing fatalities and serious injuries in general aviation accidents."

Although the spark plugs displayed significant wear, a test run of the engine revealed no anomalies that would have precluded normal operation. A carburetor icing probability chart showed the airplane was operating in conditions conducive to serious icing at glide power; however, the airplane should not have been susceptible to carburetor icing at the cruise power setting at which it was operating. The investigation could not determine a reason for the loss of engine power.

Text from the NTSB. Open the NTSB docket for CEN16FA210 for the full record.