Page 18 - Volume 15 Number 5

2 and 3 quarts down. (To be clear, that’s between the 2nd and 3rd hashmarks below “Max Cold” on the stick on a cold engine.) Some engines stake their claim at 3 or even 3.5 quarts low.
Many times there will be a disparity between your engines – the left side is happy at 2-down, but the right side prefers 2.5-down. There is nothing wrong with this. I know it’s painful for those who want both of their engines to be perfectly matched along every parameter, but they are not identical twins. As long as each engine makes book figures, you are good to go.
If your King Air is new to you, you need to fly the airplane for a bit to see where your engines want to be oil-wise. If you just had an engine overhauled, you need to fly it for a while to see if the preferred level has shifted. If it goes from 1-down
to 2-down fairly rapidly, don’t worry right away. Maybe it will go to 2.5- down and stay there. Your engine will tell you its preferred level. Once that level is ascertained, don’t add oil until the engine has gone down a quart below that level.
Finding the preferred oil level for each of your engines is crucial to monitoring engine oil consumption. All oil added in excess of that level is just blown out the breather, making a mess and wasting money.
When to check
Pratt & Whitney recommends the oil level on a PT6 be checked within 20 minutes after shutdown. I know this flies in the face of everything drilled into your pilot psyche from when you first learned to fly. Checking the oil is a vital part of the all-important preflight routine. So
why would the engine manufacturer recommend doing it after a flight?
Here’s what happens in a PT6: After running, the oil has collected in the oil tank located above the oil filter housing; however, if the oil is able to get around the housing and travel down to the accessory gear box and the bearing areas below, it will go there. It’s called oil migration, and it’s common in PT6s. Therefore, Pratt says to get an accurate read on the amount of oil in the engine, you need to check it before the oil starts to migrate, and that is within 20 minutes after shutting down.
Checking cool or checking hot?
In reality, the engines are still pretty hot after 20 minutes. You must exercise caution to check the oil without burning yourself. ›
16 • KING AIR MAGAZINE
JUNE 2021