Champion 8GCBC N424A accident near Foley, Alabama

Probable cause

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

NTSB analysis

The commercial pilot was conducting a banner-tow flight with a pilot-rated passenger. A witness (a ground crewmember) stated that, after takeoff, the approach and pickup of the banner appeared normal and that the engine sounded strong. According to the ground crewmember, the pilot successfully hooked the banner with the airplane tow cable and initiated a steep climbout with the banner in tow. The trailing edge of the banner had just come off the ground when the airplane reached an altitude of about 300 ft above ground level. At that point, the right wing dropped. The pilot attempted to maintain directional control by releasing the banner and applying left rudder; however, the airplane entered a right descending spin to the ground. Postaccident examination revealed no malfunctions that would have precluded normal operation of the airplane or engine.

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 airplane exceeded the critical angle of attack and entered an aerodynamic stall and spin from which recovery was not possible due to the airplane's altitude at the time. Even though the weight and balance were within limits for the accident flight, it is possible the presence of the back seat passenger reduced the airplane's performance, and that the pilot did not account for the effect of the back seat passenger on the performance of the airplane during the pickup maneuver.

Text from the NTSB. Open the NTSB docket for ERA18FA208 for the full record.