Accident Overview
On June 14, 2021, at 0852 eastern daylight time, a Cessna 180K, registration N13159, was substantially damaged during a forced landing near Columbus, Ohio. The pilot, who was the sole occupant, sustained minor injuries. The airplane was being operated as a personal flight under Title 14 Code of Federal Regulations Part 91.
Pilot Report
The pilot reported an uneventful takeoff and a climbing right turn, leveling off at 1,000 feet above ground level. Shortly after, the engine sputtered briefly. The pilot contacted air traffic control and initiated a 180° turn toward the airport when the engine lost all power. Unable to reach the airport, the pilot turned left toward an open field. She also noted that the airplane's radios lost power. The airplane struck trees in a heavily wooded area short of the field before impacting the ground. The wings and empennage sustained substantial damage.
Examination Findings
Fuel System
Examination of the right wing revealed the fuel tank intact with no anomalies. The fuel cap was missing, but no fuel staining was evident. In the left wing fuel tank, investigators found loose fragments of off-white sealant, up to about 1 inch in size, consistent with Chem Seal 3204. The sealant, applied to vertical and lower skin structures, showed cracking and flaking. Middle and outboard wing drains had a grey sealant over the off-white sealant, and about 12 pieces of grey sealant were loose in the tank. The left fuel cap was in place. Finger screens in both tanks were clear of debris.
The fuel strainer contained fuel with no water. A minor dark substance was observed in the strainer screen, but the screen was otherwise clear. Air blown through fuel lines at both wing roots expelled fuel through the strainer. The fuel selector valve functioned normally.
Engine
No visual signs of catastrophic failure were found. Examination of fuel components identified a minor blockage in the No. 2 nozzle and a white powder on the surface of the fuel distributor spring on its larger side. The fuel control unit displayed minor leaking at the fuel metering unit. The electrical system was not tested.
Maintenance History
Review of maintenance logbooks showed that on June 10, 2021, four days before the accident, the left fuel tank was drained and resealed with Chem Seal CS3204B2. The entry noted that the tank was refilled with 100LL and leak checked. The mechanic was not interviewed. According to Chem Seal documentation, the surface for application must be free of contaminants, and the sealant has a specific mixing and cure schedule.
Laboratory Analysis
The NTSB Materials Laboratory examined residue from the fuel distribution spring and sealant fragments using Fourier Transform Infrared spectrometry. The residue was not consistent with the sealant sample, and its source could not be determined.