Have you ever wondered what is going on, or went on, when the test set you are using only provides you with a green or red light result? <Read More>I for one, admittedly for years, did not give it a second thought, and mostly was hoping for a green light (pass) so I could finish my tasks. It wasn’t until I had to develop justifications for why a functional test may have passed, but the mission the aircraft was assigned to failed, that I became concerned with the test results.
The truth is that most simple lamp test sets do nothing more than check for continuity and stray voltage. So when the test set shows a pass, most likely it’s only telling you the wire is present. This type of testing, even in a traditional analog system, leaves huge portions of the aircraft system untested. For a young maintainer this might not seem like a problem, but for the pilot having to fly into harm’s way for a mission, system failure is NOT an option.
In aircraft electrical test, the test results are only as good as the level of test fidelity the test set is designed for. Simply put, you will only know if a wire is present vs. knowing if the system will function in its intended manner. With the advent of Smart munitions, which now communicate with the aircraft digitally, old legacy lamp test sets have become obsolete, lacking the ability to communicate with the aircraft digitally to provide a full systems test.
Due to this, the results provided to the maintainer, although they provide a pass or fail, are nothing more than “wire present or broken” results. It isn’t until the munition is loaded onto the aircraft, the pilot inputs the munition into the computer, and in some cases after the aircraft has launched, that the true status of the system is understood, which could result in a failed mission.
30 years ago armament systems were simpler, Smart munitions were nonexistent, manpower was more abundant, and operational needs were different. Today, due to budget and manning cuts, aircraft systems becoming more advanced and munitions becoming more complex, it is paramount that the test sets which maintainers use keep up with the changing times, providing the highest-fidelity test results possible.