In our Essentials of Troubleshooting course we talk about using the tools we have to aid in troubleshooting. One of those tools is the aircraft itself. We call it White Glove Troubleshooting.
When we operate a system on the aircraft there are usually some indications in the cockpit. Those indications tell us if the system is working or not. For example, when we push a button and it lights up. Is it the action of pushing the button that causes the light to come on? Usually it isn't. It is usually an indication that something else in the system worked. It could be a relay or contactor that was energized causing the light to come on. So therefore if the button does not light up when you push it (ruling out light bulbs) we can figure out what did not work.
Many times we may be troubleshooting a system that there is a duplicate system on the aircraft. Think Windshield Heat, Generators, Boost Pumps as well as many others. As we are troubleshooting the faulty system we can use a like "good" system to help us with voltages, resistances, amperage etc. For example if a windshield heat system has failed and we suspect that the heating element in the windshield is bad. We wouldn't want to change the windshield just to see if that fixes it. Chances are there is a good windshield on the other side that we can use as an example for proper resistance.
Unfortunately the aircraft maintenance manual does not always give us specific voltages or resistances for every component on the aircraft. Let's say we suspect a relay is faulty. We could order a new one, wait for it to arrive and hope that it fixes the problem. But chances are there is another relay, or dozens of them, that we can use as an example to check resistance values to verify if it is the relay that is indeed bad.
Don't forget to use all the tools you have available to you. The biggest one is the aircraft itself. Another tool is training. Call us today to set up an Essentials of Troubleshooting class.
*This information is provided as a reference only. Please see your Aircraft Maintenance Manual for proper procedures.