I'm going to start off with a reminder: You've checked that you put on the AN-818 B-nut and 819 sleeve before starting the flare, right? Right! You've been warned! Firewall-aft (FWA), rigid fuel lines ...

Before braided stainless there was rubber hose. Rubberhose, although perfectly adequate for most automotive plumbing requirements (fuel, water, vacuum, tranny fluid, and other low-pressure substances) ...