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mjschofield
4th Aug 2001, 12:12
In the MD-11, when Dual Land engages, the tie busses are tripped to isolate the 3 systems (AC & DC).

In the case of a subsequent engine fail, does the EPCU reconfigure to ensure continued power on the affected bus?

Similarly, after DL, if the pilot disengages the autopilot, does the EPCU revert to parallel mode?

downfourgreen
8th Aug 2001, 05:29
ffs,
If the busses do not split, DL will not be available. Redundancy requirements for DUAL LANDING:
2 fully operational FCCs (AP1 by AC Gen Bus 1, Eng #1, and AP2 by AC Gen Bus 3, Eng #3, and associates DC busses)
3 Fully operational IRUs
A/T engaged
Dual ILSs tuned operational, identified with valid ILS courses
Dual radio altimeters operational
3 Hydraulic Systems
In short, if redundancy is not satisfied for DL, system will revert to Single Land or APPR ONLY. After disengaging the A/Ps, EPCU will revert to parallel mode again. IDGs operate in the parallel mode except for Dual Landing operation and when using GPU, on the ground, of course.
Regards.
DN4GREEN