In the Alpha Strike Manual, under alternate ammunition, the following paragraph exists for Air to Ground Arrow IV.
"If the attack is made while the airborne unit is over the ground map, this attack is resolved using the on-board artillery rules. If the attack is made from the Central Zone or Inner Ring without the airborne unit on the ground map, the attack is resolved as off-board artillery." --Alpha Strike pg. 78
When would an Aerospace fighter be able to be in the Central Zone making an attack, but not on the ground map?