G8000,
EEC Modes
The EEC (Engine Electronic Controller) mode switches allow manual selection of the EEC (Engine Electronic Controller) mode and show the EEC (Engine Electronic Controller) mode of operation. There is a switch for each EEC (Engine Electronic Controller) on the P5 overhead panel. The normal switch position is IN (NORM).
There are the three modes of EEC (Engine Electronic Controller) operation. In Normal mode, the EEC (Engine Electronic Controller) mode switch is selected in and NORM appears. In Soft Alternate mode, the EEC (Engine Electronic Controller) mode switch is still selected in and both NORM and ALTN appear. In Hard Alternate mode, the EEC (Engine Electronic Controller) mode switch is manually selected out and only ALTN appears.
In Normal mode operation, the EEC (Engine Electronic Controller) calculates TPR (Turbofan Power Ratio) and commands the FMV (Fuel Metering Valve) to establish closed-loop TPR (Turbofan Power Ratio) control. The EEC (Engine Electronic Controller) compares the commanded TPR (Turbofan Power Ratio) to the actual TPR (Turbofan Power Ratio) and adjusts the fuel flow as needed. The TPR (Turbofan Power Ratio) target, command, reference, actual, and maximum appear on the EICAS (Engine Indication and Crew Alerting System)TPR (Turbofan Power Ratio) dial.
Soft Alternate mode operation occurs when the EEC (Engine Electronic Controller) is unable to calculate TPR (Turbofan Power Ratio). This reversion occurs automatically, and the TPR (Turbofan Power Ratio) dial goes blank. In Alternate mode, thrust commands are calculated from the TRA (Thrust Resolver Angle) and N1. Soft Alternate is an unrated mode and therefore no engine target, reference, maximum, red line, or command appear on the TPR (Turbofan Power Ratio) dial. However actual N1 speed and red line limit are available on the N1 dial.
When in Alternate mode (soft or hard), careful engine handling is required to prevent engine damage and possible exceedances.
After 10 minutes in Soft Alternate mode, the EEC (Engine Electronic Controller) will automatically change to a Hard Alternate mode without crew selection. However, it is still a crew action to select both engines to Hard Alternate mode to avoid thrust lever split.
These EEC (Engine Electronic Controller) mode switches are for mode select only. They do not control power to the EEC (Engine Electronic Controller).
Только это все RR.......