Accident Overview
On July 6, 2019, at approximately 2038 eastern daylight time, a Piper PA-18-150, registration N796AB, sustained substantial damage during an accident near Bay City, Michigan. The commercial pilot suffered serious injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 banner tow flight.
Flight Details
The pilot had completed a three-hour flight and was scheduled for a half-hour banner tow flight before ending operations for the day. After successfully dropping the banner and preparing to pick up another banner stationed on the ground near the runway, the airplane was observed remaining level to slightly nose up. The pilot did not add power. The airplane then pitched up and abruptly banked left. Witnesses reported hearing the pilot apply full power during the loss of control. The airplane impacted the ground in a direction 180° from the direction of flight. The airplane was not connected to a banner at the time of the accident. The banner, tow rope, and tow hook had been staged properly in the drop zone. The operator stated that the airplane "slowed to a[n] airspeed to slow to sustain controlled flight and a stall crash followed."
The pilot, due to his injuries, was unable to recall the events of the accident flight. The operator reported that the pilot conducted the banner drop without adding sufficient power to sustain controlled flight and that after releasing the banner, the pilot's attention was diverted for unknown reasons.
Aircraft and Equipment
The airplane sustained substantial damage to the fuselage, both wings, and the empennage. The operator reported no preimpact mechanical malfunctions or failures with the airframe, engine, banner, or tow equipment that would have precluded normal operation. The airplane was equipped with vortex generators mounted on the wings just aft of the leading edge and on the underside of the horizontal stabilizer via Micro AeroDynamics Supplemental Type Certificate SA00530SE. The airplane was not equipped with a stall warning system or an angle of attack indicator, nor was it required to be.
Operator and FAA Guidance
The operator, Air America Aerial Ads, LLC, is based in Genoa, Ohio, and operates under FAA-issued Certificate of Waiver J550 for banner towing operations. The FAA publication Information for Banner Towing Operations FS-I-8700-1 notes that stalls during banner pickup are a frequent cause of accidents and states that a stall occurs when an airfoil reaches a critical angle of attack, independent of airspeed. The document recommends for banner drop that the minimum airspeed be 1.2 times the stall speed, and for pickup, an approach speed of 1.6 times the stall speed. The operator's checklist specified a banner drop speed of 60–70 mph into the wind and a pickup approach speed of 80 mph into the wind.