Minimum Oil Level

Sure, and Lycoming also says that an engine can burn up to around 1 quart of oil every 4 hours, and still be airworthy (0.006 lbs. / HP / Hr). Of course you would never want to get anywhere near that. These are maximum/minimum limits - not recommendations.
 
I knew my O-320-D3G minimum oil quantity was 2 qts, but it wasn't listed in the Limitations section of the POH. I KNEW it was in there somewhere. Searched on "minimum" and found it in Section 8.19 - AIRPLANE HANDLING, SERVICING AND MAINTENANCE/OIL REQUIREMENTS
"The oil capacity of engine is 8 quarts, and the minimum safe quantity is 2 quarts."

Frankly 2 quarts doesn't sound "safe" to me.
 
If you combine both limitations, you could fly with only 2 qts in the sump while the engine burns 1 qt every 4 hours, which means as soon as you take off, the engine won't have enough oil.
 
MRC01 said:
Sure, and Lycoming also says that an engine can burn up to around 1 quart of oil every 4 hours, and still be airworthy (0.006 lbs. / HP / Hr). Of course you would never want to get anywhere near that. These are maximum/minimum limits - not recommendations.
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Thinking is expected of the pilot.

Or, at least it was when these things were written. Now we have a couple of generations of pilots spoiled by modern cars that require one to push the button to start it, then you point it where you want to go and press Go or Stop. Very little maintenance required, almost no oil consumption at all, so it gets driven until it finally quits and the driver gets to wait for help. This sort of thing never did work in aviation, and still doesn't.
 
Domenick said:
Frankly 2 quarts doesn't sound "safe" to me.
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Here we have a thinking pilot. I wouldn't consider it safe either, especially if the engine was tired and used lots of oil, or if the oil cooler hoses were old and could start leaking at any time, or if the engine tended to run hot at that level.
 
I don’t think anyone is suggesting you fly around with 2 quarts of oil, but when you land and discover you only have 2 quarts left, is that you don’t have to worry if your engine was damaged…….
 
MRC01 said:
If you combine both limitations, you could fly with only 2 qts in the sump while the engine burns 1 qt every 4 hours, which means as soon as you take off, the engine won't have enough oil.
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Yup.

But any Lyc/Cont opposed engine that burns that much oil needs an overhaul. That's over 12 quarts in 50 hours.
 
Dan Thomas said:
But any Lyc/Cont opposed engine that burns that much oil needs an overhaul. That's over 12 quarts in 50 hours.
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Not necessarily. That much oil consumption can be caused by a stuck oil ring, which can often be cleared by a solvent flush.

The O-290 in my Hatz was burning more that that... but compressions were good and the plugs were clean. It was annoying, but not a safety of flight issue, and O-290s are known to consume oil even when not overfilled. I planned to do a solvent flush this spring, but sold the plane (with full disclosure) before I got around to it.
 
Dan Thomas said:
But any Lyc/Cont opposed engine that burns that much oil (0.25 qt / hour) needs an overhaul. That's over 12 quarts in 50 hours.
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Dana said:
Not necessarily. That much oil consumption can be caused by a stuck oil ring, which can often be cleared by a solvent flush.
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True. The point is there is something wrong with the engine that needs attention - whether or not it is an overhaul.
 
Garee said:
I don’t think anyone is suggesting you fly around with 2 quarts of oil, but when you land and discover you only have 2 quarts left, is that you don’t have to worry if your engine was damaged…….
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Agreed, that is how I interpret the Lycoming guidance.
 
Keep in mind that some of that oil lost may not be being burned or spit out the breather tube. It could be coming from a bad crankshaft seal.
 
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