It has been said that oil is the blood of an engine. If the oil is old and tired, contains foreign materials or flows at the wrong pressure, the engine’s optimum life span can be threatened. All pilots should know enough to check oil quality, as well as quantity, during preflight inspection. A quick peek at oil quantity marks on the dipstick isn’t enough. During preflight, you need to determine whether the oil seems suspiciously gritty, displays an unusual color or sheen, seems too thin or too thick for the ambient temperature, or has a “burnt” aroma. Inspect inside the cowling and on the ground under the engine for signs of oil leaks. And, for security, check whatever parts of the oil system may be visible, including hoses, the oil cooler and the filler pipe. To avoid having your lengthy preflight become a waste of time that creates, rather than prevents, a hazardous condition, you also need to make sure that you’ve secured whatever you opened for inspection. Take, for example, the following accidents.
• A Cessna 150M with a student pilot on board was substantially damaged during a forced landing attempt. The flight originated at Grand Ledge, Mich., and was en route to Mount Pleasant, Mich., in day/VFR conditions.
