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| Maintenance OH WOW! |
Some Interesting Things are Discovered during routine Maintenance.
We would like to share with you some of the things we find during routine maintenance. Hopefully they will help you keep your aircraft in tip top shape.
If you have a little oil leak maybe you should look for the source. Here is one reason you can't just ignore these!
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A small problem which had been ignored. This could have led to BIG problems for the pilot.
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Here is a view from inside this cylinder.
Moral.
Don't ignore oil leaks!
Watch oil consumption!
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Oil: Fill Her Up, or Not
Common ramp wisdom says that if you fill your Lycoming, Continental, or Franklin opposed piston engine to the top of the mark on the oil dipstick, you will make a mess in the first hour of flight. A quart or two will deposit itself on the belly of the aircraft; even if you have an oil breather-separator you will notice the oil has gone someplace. This is true for factory new engines, the field rebuilt, or an engine on it last few hours before overhaul. The kind of flying makes little difference; local traffic patterns, cross country, or even aerobatics will dump the top quart or two.
Many pilots put this off to old technology and primitive systems. The truth is a little more complex.
FAR 33.39(a), certification of aircraft piston engines, says the engine must function at normal temperatures and pressures in all expected flight regimes, and do this with only one half of the oil supply in the engine. This "one half" is determined by the quantity marked on the dip stick. Most (but not all) four cylinder engines are marked for eight quarts; most six cylinder engines are marked for 12 quarts.
To meet the requirements of FAR 33.39(a), the engineers had to mark the dip stick to a higher level than needed under normal circumstances. This higher level in the sump leads to higher crank case pressures and / or foaming, both of which will cause the oil to depart through the breather or ascend into the combustion chamber. When the quantity in the sump is down one or two quarts, the pressure drops and consumption is back to normal for that engine.
So, now you know. As long as the pressure and temperatures are in the normal range, you may safely operate the engine one or two quarts low. Follow the manufacturer's recommendations for type of oil, change interval, and minimum safe operating quantity.
If you are flying a heavy load on a hot day, consider topping the oil supply and sacrificing the first quart or two - after all, this is the condition the FAA was considering when they wrote FAR 33.
Any A & P will tell you oil is the least expensive consumable for your engine. Check the oil level before each flight, change it as recommended, and your engine will "pay you back".
Created on 12/14/2005 03:32 PM by cliffm
Updated on 07/19/2011 10:14 AM by Cindy
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