Ah, I see. Yep, the chances to hit a plane with Infernos are rare, but should always be taken. ASFs have VERY unforgiving heat curves, so odds are after a strike or strafe a plane will be right at the edge of heat dissipation, or overheating badly. Given that heat penalties that merely inconvenience a 'mech can be lethal to a fighter, any heat you can pump into them is a good idea. Do note that flaming bombers is futile unless you hit the full 15 heat and the plane has only the absolute minimum of heat sinks(or is already hot), since a plane delivering bombs generates no heat with the attack.