N3036M

On July 31, 2023, at 1130 eastern daylight time, a Piper PA-12 airplane, N3036M, was substantially damage when it was involved in an accident near Myrtle Beach, South Carolina. The commercial pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 banner tow flight.

The pilot stated that he was towing a banner about 500 ft above ground level parallel to the coastline when the airplane’s engine stopped producing power. He restarted the engine once, but it lost power moments later; the pilot made a forced landing in the ocean. The airplane landed just offshore of the beach, which resulted in substantial damage to the fuselage.

According to the mechanic who recovered the airplane from the ocean, there was no visual evidence of fuel sheen in the water and no odor of fuel around the airplane. He visually inspected both wing tanks by removing the fuel caps and using a flashlight to inspect inside each tank. Both fuel tanks were intact and completely empty of fuel. The airplane was dragged to shore where the mechanic removed both wings – again, no fuel was drained from the tanks and no breaks in the fuel lines were observed. The mechanic said the fuel selector was in the “both position,” and both fuel “sight” gauges were empty.

The pilot said he refueled the airplane the day before the accident and performed a preflight inspection on the morning of the accident before his first flight of the day (the accident was the second flight). During the preflight inspection, the pilot said he visually inspected both fuel tanks for fuel, and then took fuel samples from the sump drains and found no water/debris. He reported departing with 33 usable gallons of fuel.

The airplane was recovered and initially taken to the operator’s facility, where a mechanic removed the carburetor drain plug. The mechanic said the carburetor was full of seawater, and there was no fuel in the firewall fuel strainer (gascolator). He also said the engine’s crankshaft rotated freely when manually rotated. The airplane was moved to a salvage facility where it was later examined by the National Transportation Safety Board (NTSB).

Examination of the airplane revealed continuity of the fuel system from both wings to the engine. Both fuel selectors were in the “on” position and the fuel strainer was undamaged and still attached to the firewall. The strainer bowl was removed and half-full of 100LL fuel along with a small amount of water. The screen was absent of debris. The line between the fuel strainer and carburetor was removed and a small amount of fuel was observed. Shop air was blown through the fuel lines at the wing root, and fuel spray was observed coming from the fuel strainer. The carburetor remained secure to the engine and was removed. The drain plug was corroded and was easily pulled out by hand. There was no fuel in the drain, and the finger screen was absent of debris. The carburetor was disassembled, and a small amount of rust colored fluid was observed in the injector chamber along with some corrosion.

The engine’s crankshaft was manually rotated via the propeller flange. The crankshaft rotated about 180 degrees and locked up before valvetrain continuity or thumb compression could be fully established.

Each cylinder was visually examined with a borescope, and some debris was noted in the No. 3 cylinder. However, no evidence of any preimpact mechanical malfunctions or failures were observed that would have precluded normal operation.