Piper PA-28-140 N32396 accident near Orange, Virginia

Probable cause

The student pilot's failure to maintain adequate airspeed after takeoff, which resulted in the airplane exceeding its critical angle-of-attack and experiencing an aerodynamic stall.

NTSB analysis

The student pilot was departing on a solo cross-country flight. Witnesses reported that they observed the airplane taking off and that it appeared to be "abnormally slow" and did not seem to be gaining altitude. They also reported observing a trail of "smoke" or "exhaust" emanating from the engine. When the airplane was about 150 ft above ground level, its nose pitched up abruptly, the left wing dropped, and the airplane impacted terrain about 1,300 ft from the departure end of the runway. Ground scars and damage to the airplane were consistent with a near-vertical impact.

Postaccident examination of the airframe revealed no anomalies, and there was no evidence of fuel contamination. Engine powertrain and valve train continuity was established, and borescope examination of the cylinders revealed no anomalies. The spark plugs were removed, and all of them exhibited significant carbon-fouling. During testing, three of the eight plugs displayed weak and intermittent spark. Flow testing revealed that, throughout all power settings, the carburetor produced a fuel flow that was richer than the maximum acceptable limits prescribed by the manufacturer. Review of the airplane's maintenance logbooks indicated that the carburetor was last serviced about 2 years (300 flight hours) before the accident. The condition of the spark plugs, as well as the witness accounts of smoke/exhaust, was consistent with the engine operating in an overly rich fuel/air mixture condition; however, the investigation could not determine how long the engine had been experiencing this condition.

None of the witnesses reported rough engine operation or a loss of power before the accident, and each of the witness observations was consistent with an aerodynamic stall/spin. Although the effect of the fouled spark plugs and overly rich fuel/air mixture on the engine operation could not be determined, it is possible that the engine's performance was degraded during the takeoff, which would likely have been a source of distraction for the student pilot and may have contributed to the loss of control.

Text from the NTSB. Open the NTSB docket for ERA15FA170 for the full record.