CFM56-7B Electronic Engine Control System Performance During Ground Run-Up Test

The performance of the Electronic Engine Control (EEC) system is essential for ensuring safe aircraft operation following engine maintenance. This study evaluates the EEC performance of a CFM56-7B turbofan engine during an on-aircraft Engine Ground Run-Up (EGR) test conducted after engine replacement on a Boeing 737-800 Next Generation aircraft. The test was performed under controlled ground conditions in accordance with the Aircraft Maintenance Manual, and key EEC-controlled parameters—including fan speed (N1), compressor speed (N2), exhaust gas temperature (EGT), fuel flow, lubrication parameters, and engine vibration—were recorded using the aircraft’s built-in sensor system. The results indicate that all monitored parameters remained within manufacturer-specified acceptance limits during engine start, idle, Maximum Power Assurance, and static take-off power conditions, demonstrating stable EEC regulation under both transient and steady-state operation. Fuel consumption during the EGR procedure was consistent with the applied power settings, reflecting appropriate fuel scheduling. Comparison with representative test-cell–based studies show similar performance trends, with expected differences in thermal behavior attributable to on-wing installation effects during ground operation. Overall, the findings confirm that on-aircraft EGR testing provides an effective and operationally representative approach for post-maintenance validation of EEC performance, bridging the gap between test-cell evaluations and actual aircraft operation.