Cessna 172 N734SY accident near Lynchburg, Virginia

Probable cause

A total loss of engine power for undetermined reasons.

NTSB analysis

About three weeks before the accident, overhauled cylinder assemblies were installed in the airplane’s engine, which was then returned to the owner for installation; no engine test run was performed. Six days before the accident, the engine was overhauled as a result of “no oil pressure.” The purpose of the accident flight was to break in the engine after the overhaul. According to the pilot, the preflight inspection was normal, oil and fuel levels were at capacity, and the engine runup was normal.

The pilot added power for takeoff, the airspeed started to increase, and the tachometer read about 2,200 rpm with all systems normal. During the climb, about 1,300 ft above mean sea level, the engine lost all power and the propeller stopped rotating. The pilot then turned left (the direction of the departure airport) and made a distress calls on the common traffic advisory frequency for the departure airport. As he approached an open area for a forced landing, the left wing hit a tree, which yawed the airplane 90 degrees. The airplane then impacted the ground, bounced, hit the ground again, and slid to a stop. The airplane sustained substantial damage to the left wing and the engine mount.

Postaccident examination of the airframe and engine revealed that the fuel strainer contained a fine, sandy material in the bottom of the bowl that had a red-colored tint. Fuel remained in the fuel strainer, and when that fuel was tested with water-finding paste, no water was present. Minor debris was found in the bottom of the carburetor bowl, but the main jet was unobstructed. While some debris contamination was found within the fuel system, it was not present in sufficient quantity to reasonably result in the total loss of engine power described by the pilot. The oil filter contained a large quantity of oil consistent with engine assembly oil. Minor amounts of ferrous/non-ferrous metal were found in the filter; the metal was likely the result of the recent engine overhaul and was typical for an engine with newly installed cylinders. While, the suction screen was not present within the oil sump. No blockages or obstructions were observed in the engine’s oil passages. No evidence of any preaccident mechanical malfunctions or failures with the airframe or engine that would have precluded normal operation were found during the examination, and the reason for the loss of engine power could not be determined.

Text from the NTSB. Open the NTSB docket for ERA24LA361 for the full record.