Accident Overview
On December 21, 2022, at approximately 1447 eastern standard time, a Cessna 172F (registration N8768U) was involved in an accident near Auburn, Michigan. The airplane sustained substantial damage, and the pilot received minor injuries. The flight was conducted under Title 14 Code of Federal Regulations Part 91 as a personal proficiency flight.
Pilot Account
The pilot reported that the flight was intended for practice of steep turns, stalls, and two landings. Prior to departure, he added Marvel Mystery Oil to the 7 quarts of Aeroshell 100 (SAE 50) oil already in the engine, with the intention of thinning the oil. He noted that during engine runup and takeoff, the oil temperature gauge was not registering, and he could not recall if the oil pressure indication was within normal range. During the climb to cruise altitude, the engine began to cough, shudder, and run rough, with engine speed dropping to 1,700 rpm. The pilot diverted back to the departure airport but was unable to restore power. On approach for an off-airport landing, the engine seized when he reduced power to idle. The airplane was high and fast, clipped trees along the intended landing road, and sustained damage to both wings, the horizontal and vertical stabilizers, the fuselage, and the engine mounts.
Postaccident Examination
A Federal Aviation Administration (FAA) aviation safety inspector examined the airplane and found the underside covered in engine oil. The No. 4 cylinder connecting rod had separated, and holes were present in the crankcase above that cylinder. The externally mounted oil cooler showed fresh oil leakage exiting from the bottom cowl. Investigators observed an oil trail leading from the hangar to the runway. The airplane was not equipped with a Cessna winterization kit for cold weather operations below 20°F, nor was such equipment required.
Cold Weather Considerations
The pilot did not preheat the engine before start and did not warm it to operating temperatures before takeoff as specified in the Airplane Owner's Manual for cold weather operations. The manual recommends SAE 20 oil at temperatures below 40°F; at the time of the accident, the temperature was 28°F. The oil in use, Aeroshell 100, has an operating range of 60° to 80°F and had been filled approximately 3 months earlier while the airplane was based in Las Vegas, Nevada. Textron Aviation states that Cessna and Continental Motors do not recommend adding any oil additives during cold weather. Teledyne Continental Motors Service Information Letter 03-1 warns that failure to properly preheat a cold-soaked engine may result in congealed oil blocking flow, leading to engine damage and failure.