Aux Fuel Pump Flow Oddities
Posted: Fri Jun 24, 2022 6:45 pm
I've been enjoying this excellent aircraft. As I understand it, a lot of the leaning is done to the specific fuel flows described in the manual, which I've been trying to master. I recently ran into an interesting oddity regarding fuel flows and the aux pumps.
At sea level, putting the pumps on low increases fuel flow, which makes sense. While climbing with one on and one off, starting about 4000 feet, the fuel flows start to converge. By about 6000 feet, setting the pumps to low does not change fuel flow (putting them on high does change fuel flow). However, when I descend in the same configuration, the fuel flows stay constant with one pump on and one off. And when starting at a 5000 foot airport (KPRC, FWIW), I see no difference in fuel flows.
Initially, I thought it was an altitude effect, but it seems a little erratic for that. It's possible there is a nuance to how these systems work that I'm not aware of, but I suspect a bug. Thanks!
At sea level, putting the pumps on low increases fuel flow, which makes sense. While climbing with one on and one off, starting about 4000 feet, the fuel flows start to converge. By about 6000 feet, setting the pumps to low does not change fuel flow (putting them on high does change fuel flow). However, when I descend in the same configuration, the fuel flows stay constant with one pump on and one off. And when starting at a 5000 foot airport (KPRC, FWIW), I see no difference in fuel flows.
Initially, I thought it was an altitude effect, but it seems a little erratic for that. It's possible there is a nuance to how these systems work that I'm not aware of, but I suspect a bug. Thanks!