ERA24LA179

The airplane had not been used for 2 years following an engine overhaul. A mechanic completed an annual inspection of the airplane, and when he and the pilot performed a preflight inspection before beginning the multi-leg trip, they found that the fuel contained, “a lot of water.” They fully fueled the airplane, allowed it to settle overnight, and then “shook” the airplane’s wings before sampling fuel. They also ran the airplane’s engine for two hours on the ground before departing on the first leg of the trip. At the next fuel stop, they drained about “a tablespoon” of water from the fuel system, and during the second fuel stop, they only observed about “2 drops” of water. The accident flight was the third leg of the trip. After nearly 3 hours of flight, and while descending to the destination airport with the carburetor heat applied, the engine lost total power. The pilot established best glide speed and attempted to restore engine power; however, he was unsuccessful and performed a forced landing onto a city street, substantially damaging the fuselage, empennage, and both wings. Postaccident examination of the engine revealed that one of the cylinders exhibited excessive piston-to-cylinder clearance, circumferential markings of the cylinder walls that were not consistent with the typical cross-hatching pattern that would be expected in an engine shortly after overhaul, and its intake valve was stuck open. While anomalous, each of these findings could reasonably be associated with some partial loss of engine power, but not the complete loss of engine power that was described by the pilot during the descent phase of the accident flight. The examination of the airframe also revealed rust around the fuel filler ports, indicative of water entry into the airplane’s fuel tanks. While fuel recovered from the left wing fuel tank was free from contaminants, significant water and debris were observed in fuel recovered from the gascolator and carburetor bowls. Given this information, it is likely that the total loss of engine power was due to contamination of the fuel supply with water and particulate matter.

On April 14, 2024, about 2330 eastern daylight time, a Cessna R172E, N3FR, was substantially damaged when it was involved in an accident near Rocky Mount, North Carolina. The pilot was not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 positioning flight. The pilot fueled the accident airplane as well as the escort airplane for the positioning flight at Delaware Airpark (33N), Dover, Delaware. He completed a full preflight inspection of the accident airplane, including visually checking the fuel tanks, and then performed an engine runup with no anomalies noted. He departed 33N at 2030 for Rocky Mount/Wilson Regional Airport (RWI), Rocky Mount, North Carolina, with 46 gallons of fuel. The departure and enroute portions of the flight were uneventful. Nearly 3 hours into the flight, and a few minutes after the pilot reduced engine power and applied carburetor heat to begin the descent into RWI, the engine sustained a total loss of power. He confirmed that the fuel selector was set to BOTH, turned the auxiliary fuel pump on, enrichened the mixture, and attempted to restart the engine both with the carburetor heat on and with it off; however, the engine did not regain power. With no time for further remedial action, the pilot performed a forced landing to a lit road. The airplane impacted power lines before coming to rest near an intersection. Examination of the wreckage by a Federal Aviation Administration inspector revealed that the main wreckage came to rest canted at a 45° angle, with substantial damage to both wings, the fuselage, and the empennage. There was no evidence of fire. The pilot stated that he performed a fuel calculation for the flight before departure, with a planned cruise at full power for engine break-in, since the engine had recently been overhauled. He calculated a fuel burn of 30 gallons, with 16 gallons of fuel remaining upon landing. He kept the fuel selector set to “BOTH” for the entire flight. Examination of the engine revealed continuity of the crankshaft to the rear accessory gears and to the valvetrain. Suction and compression were achieved on three of the four cylinders. The interiors of the cylinders were observed using a lighted borescope. The intake valve was stuck open on cylinder No. 3 and circumferential markings were evident the entire length of the cylinder Nos. 1 and 3 walls. The piston rings were evident at the edge of the piston face and did not seem to be properly seated. The magnetos sparked on all leads when the input drives were rotated. Postaccident examination of the airframe revealed that the left fuel tank was breached. Fuel recovered from the left wing was free from contaminants. Rust was observed at both fuel filler ports. Debris and water contamination was observed in the fuel recovered from the gascolator and carburetor bowls (see figure 1). Figure 1 - Fuel from left wing fuel tank (left) and carburetor and gascolator bowls (combined, right). Review ofmaintenance records revealed that the engine was overhauled on January 7, 2022. A mechanic completed an annual inspection of the airplane the day of the accident and in the maintenance log entry showed that the inspection occurred at 1.0 hours since major overhaul. The mechanic who completed that inspection also was the pilot of the escort airplane for the accident flight. He stated that following the engine overhaul in 2022, the airplane had not been flown for 2 years. He stated that the airplane was previously at Beverly Regional Airport (BVY), Beverly, Massachusetts and that he and the accident pilot found that there was “a lot of water in the fuel.” They fully fueled the airplane, let it sit overnight, and “shook the wings well” before “sumping” the fuel to drain water. They also ran the airplane’s engine on the ground for 2 hours before departing on the multi-leg trip to Rocky Mount, North Carolina. At the first fuel stop of the trip, they drained about 1 tablespoon of water from the fuel system, and at the next fuel stop, they observed about “2 drops” of water from the left wing and no water in the fuel strainer. The next (third) flight was the accident flight to RWI. FAA Advisory Circular 20-125, “Water in Aviation Fuels,” stated that “an important part of the preflight inspection is to drain aircraft fuel tanks sumps, reservoirs, gascolators, filters and other fuel system drains to assure that the fuel supply is free of water.” The advisory circular also stated the following: “Aircraft fuel tanks are constructed with sumps to trap water. Since it is practically impossible to drain all water from the tanks through the fuel lines, the fuel tank sumps should be regularly drained in order to remove all water from the system. It may be necessary to gently rock the wings of some aircraft while draining the sumps in order to completely drain all the water.”