I-level technicians work on the individual printed circuit boards within an actual component such as a radio. They are the technicians that connect the component to a test bench to simulate an aircraft, and troubleshoot and repair the equipment. In some instances the technician will not repair specific circuit card assemblies (CCAs); these CCAs will either go to depot level or back to the original manufacturer for repair. I-level AT's are usually assigned to fleet readiness centers on shore or aircraft intermediate maintenance departments aboard ships. The most challenging and demanding specialty that AT's can have is to be a calibration technician. Without properly calibrated gear such as test sets, oscilloscopes, spectrum analyzers, frequency counters, meters, gauges, thermometers, torque wrenches, and transducers, the rest of the maintenance ratings, for aircraft and ships alike, would not be able to do their jobs effectively. I-level AT's are expected to have some electronics engineering knowledge, and are not generally expected to know much about aircraft-specific systems.