737NG TR UNIT light
Hi,
If the TR UNIT light illuminates in flight we know that either the TR1 has failed, or both TR2 and 3 have failed.
If it is. TR1 there will be no immediate effect as the DC Bus tie stays closed and we need to do an approach in a mode other than APP mode.
If it is both TR2 and 3, is there any loss of power to systems or does the TR 1 continue to power the DC 1 and 2 busses as well as the battery bus and standby DC bus?
I can't find any information on this in my manuals. The checklist does not differentiate.