The single best option to fully test a military aircraft’s armament system would be to launch or drop munitions from the station in question, and wouldn’t this be fun for our service members involved! Unfortunately for all, this reality cannot exist for many reasons, so aircraft armament technicians are left with the task of functionally testing these interfaces. However, when the interfaces are tested, most often the process of expending the munitions is far from accurately simulated. In fact, the test sets armament maintainers utilize simply report the presence of continuity or stay voltage, omitting critical test data.
Now this situation might be sufficient if the armament system was still fully analog, but this hasn’t been the case for decades. Now firmly in the 21st century, we see most munitions and armament systems are either fully digital or hybrid analog/digital.
When a legacy munition (which operated solely off the aircraft’s analog systems) was to be employed, it simply required voltage to be applied to the arming devices and firing circuits. So, technicians could apply these voltages on the ground and use simple test sets to verify functionality. However, MIL-STD-1553 and -1760 munitions require many more parameters to launch, most of which are digital.
Modern munitions, like AMRAAM or JDAM, have numerous digital communication verification messages required to identify the munition, run BIT, establish status, and most importantly, LAUNCH. When complete, this same message traffic is used to inform the pilot of a successful or failed launch of the munitions.
As one can imagine, if digital communication is lacking from a modern test set, entire portions of the aircraft armament system would be left untested. This would result in what is referred to as a test gap. Worst of all, understanding if the armament system could, in fact, launch the desired munition would be left up to the pilot conducting the mission. This is not the time to leave a combat system untested, especially one dedicated to the survival of the pilot.
Modern aircraft, armed with modern digital munitions, require modern test equipment capable of simulating or emulating the full munition launch sequence. Simply establishing communication is not enough to ensure mission success. Enabling maintenance personnel to simulate munitions launch is critical to ensure that munitions will launch when the pilots need them to!