Hello,

I'm trying to do a cold and dark startup for the 757.
I select the cold and dark state from the FMC, turn off the battery and every other off switch I can find. Then tun the battery switch on, turn the bus ties to auto and standby power to auto. Everything then turns on like it should however the utility busses won't ever turn on. They remain lit as "OFF".
How can I do a C&D startup when it already fails right from step 1?
Anyone to enlighten me as to why this won't work? Even after I turn on the APU gen. the utility busses will remain off.

I have the same issue.  UTIL BUS should be powered whenever APU or EXT PWR is on, or engines running.  In this current version they are not powered until the ENG GENs are online.  They should shed during engine start but power up again when the ENG GENs are online.

Can confirm it's 100% an issue, when Gnd/APU power is established only thing that should be loadshedding is Center Hydraulic pump 2.

During engine start, Util busses, R Recirc should also load shed.

Captain Sim wrote on Sep 7^th, 2019 at 3:38pm:


I didn't start this thread, just inputting confirmation of a bug. Would you like me to start another thread in the proper forum? Felt it'd be a waste. Either use the information at hand, or ignore it.

EY wrote on Jan 4^th, 2020 at 2:38pm:


Will the C2 pump not being load shedded when only one AC sourse is available not be fixed?

I saw you guys kind of fixed it in a recent update, but the logic is still a little off. Currently with CS it only sheds during the first engine start. IRL, C2 is shed when only one AC source is available, and all the other ELEC pumps are on, so basically the PRESS light should be illuminated when no engines are on once all 4 ELEC pumps are on.

After the first IDG comes online, the C2 pump then operates (because now APU and an IDG are on). I'm reading it from the Maintenance Training Manual of one of the top 3 largest 757 operators, along with seeing pictures/video of a 757 just before engine start, the C2 pump clearly has its PRESS light illuminated.

In fact, at this airline, the procedure when powering hydraulics before engine start is to power R ELEC and C2 first, then wait for the pump PRESS lights to extinguish. Then, you turn on C1 and L ELEC and observe those lights extinguish, then you will see C2 PRESS light illumminate again for the load shed. Again, this is all before any of the engines are started.

Quote from that same major airline's 757/767 flight manual:

"Note: (757) The center ELEC 2 pump PRESS light illuminates when shedding
occurs as the remaining pumps are turned on and will extinguish
when two generators are powering the electrical system."