Accident Summary
On February 17, 2021, about 945 eastern standard time, a Cessna 150, registration N8428J, was substantially damaged when it was involved in an accident near Maryland Airport (2W5), Indian Head, Maryland. The flight instructor and pilot receiving instruction were uninjured. The airplane was operated as a 14 CFR Part 91 instructional flight.
Pilot Report
According to the pilot receiving instruction, he was flying with his flight instructor from Potomac Airfield (VKX), Friendly, Maryland, to prepare for his initial flight instructor check ride. He added 10 gallons of fuel, conducted a preflight inspection, and rocked the wings to release trapped water before draining the fuel tank sumps. No water appeared from wing sump samples, but water was present in the fuel strainer drain. After draining about half a tube of water from the airplane’s belly, no further water was noted.
About 90 minutes into the lesson, while performing a left chandelle maneuver, the engine "hiccupped" momentarily. The flight instructor and pilot decided to climb to 4,000 ft and proceed about 10 miles northwest to 2W5 for a precautionary landing. While over 2W5, the pilot descended in a circle. Abeam the runway numbers on a right downwind leg to runway 20, the airplane was several hundred feet above traffic pattern altitude. The flight instructor took the controls and initiated an aggressive right-wing-low sideslip to lose altitude while maintaining 1,400 rpm to prevent engine power loss. Flaps were not extended because airspeed was above the white arc.
At the runway midpoint at 100 knots indicated airspeed, the instructor executed a go-around. After climbing about 300 to 400 ft, the engine stopped producing power, and the propeller windmilled momentarily before stopping. With inadequate time for remedial actions, the instructor performed a forced landing into trees. The airplane impacted trees and descended nose down to the ground, substantially damaging the empennage and both wings.
Postaccident Examination
Postaccident examination of the airframe revealed corrosion around the exterior of the fuel filler necks. White sediment was found in fuel samples from both left and right fuel tanks. Water was recovered from the left-wing fuel tank sample and the fuel strainer assembly. The fuel strainer assembly bowl exhibited white chalky corrosion, and the strainer standpipe and sump spring tube were covered in white deposits. The fuel strainer screen exterior was obscured by white chalky deposits inside the screen. The carburetor fuel inlet screen threads in the carburetor body exhibited white chalky corrosion. The sediment was analyzed with x-ray fluorescence and found consistent with soil.
Examination of the engine revealed no anomalies; the engine was started and operated as expected during the run-up.
Regulatory Guidance
Federal Aviation Administration Advisory Circular 20-125, "Water in Aviation Fuels," states that an important part of preflight inspection is to drain aircraft fuel tank sumps, reservoirs, gascolators, filters, and other fuel system drains to assure fuel is free of water. It also notes that aircraft fuel tanks are constructed with sumps to trap water, and it may be necessary to gently rock wings while draining sumps to remove all water.