TM  1-1520-240-10 2-3-12            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 A2 DECU NR set soft fault. N/A N/A Continue Mission A3 DECU thrust hard fault. REV light Unable to start in Primary and Reversionary N/A Abort Mission A4 DECU NR soft fault. N/A N/A Continue Mission A5 DECU ECL soft fault. N/A N/A Abort Mission A6 DECU emergency bus soft fault. N/A Check REV CONT CB If CB in, Continue Mission If CB out and can’t reset, Abort Mission A7 DECU airframe bus soft fault. N/A Check PRI CONT CB Back-up power ON If CB in, Continue Mission If CB out and can’t reset, Abort Mission B2 DECU internal N1B hard fault. With REV light, Unable to start in Primary or Reversionary N/A Abort Mission B2 DECU N1B soft fault. Without REV light N/A Continue Mission B3 DECU N2B soft fault. Overspeed system compro- mised Make an entry on the DA Form 2408-13-1 even if fault code clears. Continue Mission B4 (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 B4 (All other DECU BIT checks) DECU PTIT soft fault. N/A N/A Continue Mission B5 DECU thrust soft fault. Without REV light N/A Continue Mission B5 DECU thrust hard fault. With REV light, Unable to start in Primary or Reversionary N/A Abort Mission