This was discovered on an aircraft during a condition inspection. It really was a poor installation. Nonetheless, the aircraft had been operating on unfiltered air for quite some time. It’s not the first time I have seen this. It is quite easy to check during a preflight by using a flashlight and peering up into the lower cowling from the exhaust exit.
In Case You Missed it
Counterbores
Bob Hadley - 0
Counterbore sets (front left, and back) typically cover a basic range of sizes...
Replacing Fuel and Oil Lines
Dave Prizio - 0
It is a good idea to cap off the old lines and fittings...