Piper PA-12 N4421M accident near North Myrtle Beach, South Carolina

Probable cause

The pilot's exceedance of the airplane's critical angle of attack, which resulted in a subsequent aerodynamic stall at an altitude that was too low for recovery.

NTSB analysis

The pilot of the banner tow airplane made a low approach to pick up a banner. Witnesses reported that after the tow rope was picked up, the airplane pitched up and maintained a steep angle of attack until it entered an aerodynamic stall and made a near vertical descent to impact. The airplane came to rest in a nose-down, near-vertical position about 300 ft from the banner pick up zone. A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Toxicology testing detected a low level of ethanol in the pilot’s liver tissue. Some or all of the small amount of detected ethanol may have been from postmortem production. It is unlikely that ethanol effects contributed to the accident. It is likely that after the banner pickup and during initial climb, while the airplane had a high-power setting, high pitch angle, and low airspeed, the pilot exceeded the airplane’s critical angle of attack, and the airplane entered an aerodynamic stall from which recovery was not possible due to the airplane's low altitude.

Text from the NTSB. Open the NTSB docket for ERA22FA243 for the full record.