737NG's questions

[N1 Limit]

Hey guys

I've got some doubts about this question on electrcity check it out


In flight, if the APU is supplying both AC Transfer busses, positioning the BUS TRANS switch to OFF will:

1) Cause AC Transfer bus No.1 to lose power
2) Cause AC Transfer bus No.2 to lose power

• 3) Cause both AC Transfer busses to lose power
• 4) Not cause either AC Transfer bus to fail.

For this the answer should be 3 but smartcockpit says 2 is the answer.anybody out there to help me resolve this ambiguity?

Here goes another one:

Why when you loose AC transfert Bus 1 and DC Bus 1 the battery/battery charger immediately power AC stby and DC stby Bus whereas in case you lost DC Bus 1 TRE through the cross bus tie relay can power DC stby Bus?Many thanks