Primary finding
Probable cause
An overstress fracture of the pilot’s seat, which resulted in the loss of control during takeoff and the pilot’s inadvertent movement of the fuel selector and subsequent partial loss of engine power.
Investigator assessment
Analysis narrative
The banner tow flight was in the initial climb after the pilot snagged the banner when the back of the pilot’s seat broke and the pilot inadvertently pulled back on the control yoke as he abruptly slid aft to a horizontal position. The airplane pitched up in a nose-high attitude, causing the pilot to further slide aft. The airplane was about 200 ft above ground level (agl) and at the onset of an aerodynamic stall. Using a crossbeam to pull himself forward, the pilot was able to push the flight control stick forward and recover the airplane. The airplane’s engine then began to “cough” and it sustained a partial loss of power. Unable to maintain altitude, the pilot made a forced landing to a nearby baseball field. The airplane impacted a fence along a concrete wash resulting in substantial damage. Postaccident examination of the pilot’s seat fracture surface revealed characteristics consistent with an overstress fracture. Examination of the engine revealed no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. The pilot reported that when he slid aft, the fuel selector lever may have inadvertently been moved out of the “both/on” position, resulting in the partial loss of engine power.
Source record
Factual narrative
On September 3, 2023, about 1420 Pacific daylight time, a Piper PA-18-135, N7199K, was substantially damaged when it was involved in an accident near Compton, California. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 banner tow flight. The pilot reported that shortly after takeoff, during a banner tow operation, the back of the pilot’s seat broke and he slid aft into a horizontal position. The abrupt rearward movement resulted in the pilot pulling back on the control yoke, which caused the airplane to pitch up to a nose-high attitude. Due to the high pitch attitude, the pilot slid further back in the seat. Unable to push the flight control stick forward, he let go of the flight controls and used the crossbeam to pull himself forward. About 200 ft agl, at the onset of an aerodynamic stall, he was able to push the flight control stick forward and recover the airplane. As he recovered from the imminent stall, the airplane’s engine began to “cough” and sustained a partial loss of power. Unable to maintain altitude, he elected to make a forced landing to a nearby baseball field. As the airplane descended toward a baseball field, it impacted a fence along a concrete wash and came to rest upright. The pilot believes that when he fell back or when he was pulling himself forward, his foot or knee may have moved the fuel selector lever out of the “both/on” position. Postaccident examination of the airplane revealed that both wings were substantially damaged. The pilot’s seat back frame was fracture separated on the left and right side near the back rest and seat junction. Examination of the engine revealed no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. The pilot’s seat was sent to National Transportation Safety Board Materials Laboratory, Washington, DC, for examination. The examination of the fracture surface revealed characteristics consistent with an overstress fracture. A review of the airplane’s maintenance records could not determine the age of the pilot’s seat, or if recent maintenance had been performed on it.