MD-11 Starting on Battery Power

[Guest kelvind80]

Hi there,I just have a question about starting this bird on battery power only (without ground power), from cold and dark. I'm following the Normal Procedures which is where the query is from. Obviously you turn on the battery, then switch the standby power to "Auto", then you start the APU.My question: in the 747-400, if in the same scenario, you would switch the ND to show the LOWER EICAS screen, so you could monitor the APU N1 rotation (and ensure it starts as expected)... how is this done in the MD-11? I think it's called the Systems Display in the MD-11. But so far you turn the APU PWR on and, well, hope for the best, with no visual indication as to whether the APU has started.I know if ground power was connected, you could see the APU N1 rotation as there is enough power to display all the screens.Kelvin D

[mburkhard 23]

Kelvin,you do not need to set the EMER PWR to ON for the APU to start in this scenario, you may leave it at 'OFF'. You may start the APU with main BAT only, monitoring the APU parameters during start-up is not needed so don't worry if you have no SD ENG page available. The blinking APU button light on the overhead panel is sufficient for the purpose of showing that the APU is starting up. Leave it to the APU starting system to detect abnormal conditions to abort the start-up sequence. Regards,Markus

[Guest kelvind80]

you do not need to set the EMER PWR to ON for the APU to start in this scenario, you may leave it at 'OFF'. You may start the APU with main BAT only, monitoring the APU parameters during start-up is not needed so don't worry if you have no SD ENG page available.

Hi Marcus,Brilliant, thanks for the answer. Is this how it's done in real life then? Then, if an APU problem persists, they request ground power for see more into it?Kelvin

[mburkhard 23]

Kelvin,yes this is reality. However as always there MIGHT be an airline handling this differently I'm not aware of.If the APU does not start there are various ways to proceed... If you can have EXT PWR somehow you might ask for that and try again to start the APU. Or if there's no way of having EXT PWR you might try again on Battery anyway, but you can't do that indefinitely because at some point the battery will be drained... So after a second try on battery you might want to call maintenance. If there's no maintenance available things might get nasty...Markus

[stefltt 11]

Hi, When starting in cold and dark situation, with only the battery power, without starting the APU, what is the correct procedure to ask for external power to be connected to aircraft ?Because, there is an option in the FMC for FS actions shortcuts. BUT with only battery ON, all screens are not powered, including the FMC. So how to ask for pluging external power if we can't read the FMC ? Do I have to turn the emergency power to ON, to power instruments, then ask for external power on FMC, and finally turn the emergency power to OFF ? Is that real SOP ?St

[downscc 1,327]

The MCDU FS Shortcuts are available with battery only, if I recall correctly. The FMS functions may not be available but I'm pretty sure you are not stuck on battery.

[mburkhard 23]

When starting in cold and dark situation, with only the battery power, without starting the APU, what is the correct procedure to ask for external power to be connected to aircraft ?Because, there is an option in the FMC for FS actions shortcuts. BUT with only battery ON, all screens are not powered, including the FMC. So how to ask for pluging external power if we can't read the FMC ? Do I have to turn the emergency power to ON, to power instruments, then ask for external power on FMC, and finally turn the emergency power to OFF ? Is that real SOP ?

St

[stefltt 11]

okay thanks Markus. I Will try on my next flight in a few minutes :-)