SECTION II. TROUBLESHOOTING METHODS AND CHECKS

TM 1-1520-238-T-4 1–5 SECTION II. TROUBLESHOOTING METHODS AND CHECKS 1–5. TROUBLESHOOTING THE AH–64A HELICOPTER 1–5 Troubleshooting consists of: · Using the failure symptom index(es) find the failure symptom to determine the maintenance operational check (MOC) needed. · Performing a MOC and observing indications on equipment and instruments. · Performing a FD/LS check, when applicable. · Manually locating and isolating troubles using TM 1-1520-238-T-3 (when applicable) or FIPs. 1–6. FAILURE SYMPTOMS AND TROUBLESHOOTING 1–6 Troubleshooting begins with failure symptoms. Failure symptoms are organized by system in TM 1-1520-238-T-2. Use this volume to locate what system(s) the failure is in and perform the appropriate FIPs as directed. 1–7. MAINTENANCE OPERATIONAL CHECKS (MOCS) 1–7 A MOC is provided for each system. MOCs test the system by using operator panel switches, controls and indicators. When a desired result is not obtained, a reference is made to a FIP or to the multiplex read codes found in TM 1-1520-238-T-3, based on the failure symptom. 1–8. FAULT DETECTION/LOCATION SYSTEM (FD/LS) CHECK 1–8 FD/LS checks are located in TM 1-1520-238-T-1 along with a description of the FD/LS operating modes and power applications. 1–9. ROADMAP APPROACH 1–9 When doing MOCs and FIPs, use the troubleshooting data like a road map. a. You must start at the beginning and follow to the end. · Always start with the MOC. · Do not skip or miss a step. · In flow diagrams, always start with the upper left block. · After repair, always perform the MOC. b. As shown in the troubleshooting flow diagram (fig. 1–3), if the MOC result is normal, proceed to the next step. If the result is not normal, perform the FIP indicated.