HARM? Could be being fired in Pre-Briefed mode. Just reach the programmed launch point and pull the trigger.
“The HARM has four basic operating modes. The Pre-Brief, Pre-Emptive or Position-Known (PB/PE/POS) mode is a Lock On After Launch (LOAL) mode, and is used for standoff maximum range attacks on emitters of a known type and location, within several degrees of the missile boresight. This is the basic mode used by dedicated defence suppression (SEAD) aircraft such as the F-4G and Tornado ECR, or F-16CJ/HTS.
In PB/PE/POS mode, as used by the Tornado ECR or F-4G, the aircraft's Emitter Locating System (ELS) determines the identity and position of the target, which are downloaded to the missile. The launch aircraft will then toss the missile to impart the best possible range. The missile flies on inertial guidance until it acquires the target, and then homes to impact. The PB/PE/POS mode is essentially offensive and most commonly used when taking down an IADS.”