TM  1-1520-240-10 2-3-14            Table  2-3-1. T55-GA-714A DECU BIT Fault Code List/Matrix (Continued) DECU Fault Code(s) Fault Operational Effect Pilot Action Mission Impact D4 DECU internal power sup- ply hard fault. FADEC light Unable to start in Primary N/A Abort Mission D5 DECU internal power sup- ply hard fault. DECU inter- nal hard fault. FADEC light Unable to start in Primary N/A Abort Mission D6 DECU internal hard fault. REV light Overspeed system compro- mised Unable to start in Primary and Reversionary N/A Abort Mission D6 DECU internal soft fault. Without REV light N/A Continue Mission D7 DECU internal power sup- ply hard fault. FADEC light Unable to start in Primary N/A Abort Mission D8 DECU internal soft fault N/A Make an entry on the DA Form 2408-13-1 even if fault code clears. Continue Mission D9 DECU internal soft fault. N/A N/A Continue Mission DA DECU internal power sup- ply hard/soft fault. With or without REV light May be unable to start in Pri- mary and Reversionary N/A Abort Mission DB DECU Reversionary sys- tem hard/soft fault. With or without REV light May be unable to start in Pri- mary and Reversionary N/A Abort Mission DC DECU internal PTIT soft fault. N/A Make an entry on the DA Form 2408-13-1 even if fault code clears. Continue Mission DD DECU overspeed system soft fault. N/A N/A Continue Mission DE DECU 400 HZ hard/soft fault. With or without REV light May be unable to start in Pri- mary and Reversionary N/A Abort Mission DF DECU internal hard fault. FADEC light Unable to start in Primary N/A Abort Mission E1 (DECU Pre- start BIT check) DECU PTIT soft fault. N/A Perform REV mode selected start. Switch to PRI when ground idle is achieved. Make an entry on the DA Form 2408-13-1 even if fault code clears. Continue Mission E1 (All other DECU BIT checks) DECU PTIT soft fault. N/A Make an entry on the DA Form 2408-13-1 even if fault code clears. Continue Mission