N8768UCessna 172F · 1965

On December 21, 2022, about 1447 eastern standard time, a Cessna 172F, N8768U, received substantial damage when it was involved in an accident near Auburn, Michigan. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.

The pilot stated that the accident flight was a proficiency flight, and he was planning to perform steep turns, stalls, and two landings. Before the flight, he added Marvel Mystery Oil to the 7 quarts of engine oil that was in the engine to “thin the engine oil.” He said that the airplane hangar was close to the departure runway and that during the engine runup and takeoff roll, the engine oil temperature gauge indication was “not registering.” He did not remember whether the oil pressure gauge indication was in the normal operating range. He stated that during the departure climb to cruise altitude, the engine “coughed, shuddered, and started to run rough.” The engine speed decreased to 1,700 rpm, and the pilot then diverted the flight to the departure airport. His attempts to regain engine power were unsuccessful, and he performed an approach for an off-airport landing, during which the engine seized when he reduced engine power to idle. He said the airplane was high and fast on the approach, and it clipped trees along a road that he intended to land the airplane on. The airplane sustained substantial damage to both wings, horizontal and vertical stabilizers, fuselage, and engine mounts.

Postaccident examination of the airplane by a Federal Aviation Administration (FAA) aviation safety inspector revealed that the underside of the airplane was covered in engine oil. The No. 4 cylinder connecting rod was separated, and there were holes through the engine crankcase above the No. 4 cylinder. The externally mounted engine oil cooler exhibited fresh oil leakage that exited from the bottom engine cowl. The airplane was not equipped with a Cessna winterization kit for cold weather operations below 20o F, nor was it required to be.

The FAA inspector stated there was a trail of oil leading from the airplane’s hangar down the taxiway to the runway. The pilot did not preheat the engine before start and did not warm the engine to operating temperatures before takeoff in accordance with the procedures for cold weather operations in the Airplane Owner’s Manual.

In 2013, an Aviation Development Corporation remote oil filter and an externally mounted oil cooler were installed onto the engine under an FAA field approval. The engine oil was last changed by the pilot using Aeroshell 100 (SAE 50) engine oil when the airplane was based in Las Vegas, Nevada, about 3 months before the accident. Aeroshell 100 has an operating temperature range of 60o to 80o F. The Airplane Owner’s Manual states that SAE 20 oil is to be used at temperatures below 40oF. The temperature at the time of the accident was 28°F. According to Textron Aviation, Cessna and Continental Motors do not recommend the use of any additive to the oil during cold weather operations.

Teledyne Continental Motors Service Information Letter (SIL) 03-1, Cold Weather Operation – Engine Preheating, issued on January 28, 2003, stated, in part:

Failure to properly preheat a cold-soaked engine may result in oil congealing within the engine, oil hoses, and oil cooler with subsequent loss of oil flow, possible internal damage to the engine, and subsequent engine failure.

Superficial application of preheat to a cold soaked engine can cause damage to the engine. An inadequate application of preheat may warm the engine enough to permit starting but will not de-congeal oil in the sump, lines, cooler, filter, etc. Congealed oil in these areas will require considerable preheat. The engine may start and appear to run satisfactorily but can be damaged from lack of lubrication due to the congealed oil blocking proper oil flow through the engine. The amount of damage will vary and may not become evident for many hours. However, the engine may be severely damaged and may fail shortly following application of high power.

The SIL further stated that “operation of the engine above 1700 RPM before reaching minimum oil temperature may result in engine malfunction, engine failure, injury or death.”