I think there are some misleading terms being used here. The air/fluid coupling in a free turbine engine is not the clutch. The free turbine is considered to be part of the engine although not mechanically connected (hence the fact that Bell refer to N2 as engine RPM). Therefore there is a mechanical clutch located between the free turbine and the transmission (may be actually in the transmission casing), ie a freewheel unit. If this is disengaged for any reason (not necessarily auto) the transmission will be oblivious to the fact that the engine is running, or indeed stopped. Any reference to engine assistance is only correct if the freewheel unit is engaged.
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