This is the in flight Lean of Peak mag test protocol recommended by Savvy. I have done it many times on the Continental 550 N/A in my SR22: In-Flight Lean Mag Check The in-flight lean mag check is a test of ignition system performance, and is used to help diagnose problems with magnetos, ignition harnesses, spark plugs, ignition timing, etc. Perform the in-flight lean mag check procedure by...