O-level technicians troubleshoot various discrepancies with the use of multimeters and avionics test equipment to locate faults within the aircraft. An O-level AT will determine if the discrepancy that the aircrew reported is an aircraft-wiring problem or a system problem. If the problem is aircraft wiring, the AT will repair the wiring problem on the aircraft. If the problem is determined to be an assembled component of a system, the assembly will be removed and turned in to AIMD for repair. The assembly can be replaced with parts that the squadron may keep as spares in order to keep the aircraft operational. Keeping spare parts at the squadron-level is usually not standard operating procedure, but these rules are frequently relaxed during intense operations due to the need for expedient turn-around. In addition to their separate duties as electronics technicians, O-level AT's are sometimes combined with aviation electrician's mates and aviation ordnancemen into a work center called IWT (integrated weapons team). As electronics have migrated into other aircraft systems (such as flight control and weapons control), the IWT team is given the duties of maintaining specifically the armament and weapons systems, whereas a separate AT workcenter is responsible for non-weapons based electronics such as communications and navigation. This is usually done at the organizational level, and is not Navy-wide. O-level AT's are assigned to squadrons and perform most of their work on the flight deck or in hangar bays of carriers, and on the flight line or in the aircraft hangars on land. These ATs are expected to have a detailed understanding of how the systems interface with the aircraft.