I spoke with Don at Airflow Performance this morning and questioned him about the need for the commonly advised practice of leaning while on the ground. According to Don, if your AFP fuel injection system is set up properly, there is no need for leaning on the ground. To test if you have it set up right, lean at idle and if you get more than a 0.2 inch decrease in manifold pressure, your idle mixture is set too rich. The exception to his "no ground leaning" rule is if you are away from your home base and the airport where you are located is at a significantly higher elevation than home.
I brought this up in another thread awhile back, but thought it was worthy of its own thread after confirming Don's position. His advice makes sense to me, but I am unsure if applies to all fuel injection systems or not. I also did not think to ask him about the reverse situation, where your home base airport is at a high elevation and you fly to a sea level airport; there would seem to be no way to enrichen other than to remove the cowling and adjust the idle mixture screw. Perhaps in that situation, one would want to have the idle mixture set slightly rich at your home base and lean manually as necessary
I am not sure why there is this apparent contradiction to what is commonly preached by Mike Busch and other knowledgable folks. Any thoughts?
erich
I brought this up in another thread awhile back, but thought it was worthy of its own thread after confirming Don's position. His advice makes sense to me, but I am unsure if applies to all fuel injection systems or not. I also did not think to ask him about the reverse situation, where your home base airport is at a high elevation and you fly to a sea level airport; there would seem to be no way to enrichen other than to remove the cowling and adjust the idle mixture screw. Perhaps in that situation, one would want to have the idle mixture set slightly rich at your home base and lean manually as necessary
I am not sure why there is this apparent contradiction to what is commonly preached by Mike Busch and other knowledgable folks. Any thoughts?
erich