When arriving on stand - can't turn on electric before switching off APU

[Tbo 7]

Hi,

 

When I arrive on stand I experience the following behavior:

 

- Blocks on wheels

- GPU is connected

- I get "green" available light but I can't switch it on / push on active. Nothing happens.

- I need to switch off APU first but I loose all electrical

- Only then I can switch on the electrical and everything is coming back, but sounds odd? Or is it normal?

 

Thanks

[Aplato 133]

I've never had an issue with this, though it's very difficult to tell which buttons are actually pressed down. With the APU running I pull up to the gate, connect ground power through the EFB, push the button that's lit up as available, and then turn off the APU. I've never lost power doing this.

[Tbo 7]

You can see it here: https://www.twitch.tv/tbo64/v/1137020136?sr=a&t=9040s

[Aplato 133]

It's hard to tell but it looks like you actually turned it off when clicking the switch. It seems likely that you never actually turned off that switch after starting your APU prior to departure so when you reconnected to ground power it was already active. If you just taxi away without turning the switch off, it will remain active. I have done that before, entirely self-inflicted. Not sure if that's realistic behavior or not though.

[LesOReilly 314]

5 hours ago, Aplato said:

It's hard to tell but it looks like you actually turned it off when clicking the switch. It seems likely that you never actually turned off that switch after starting your APU prior to departure so when you reconnected to ground power it was already active. If you just taxi away without turning the switch off, it will remain active. I have done that before, entirely self-inflicted. Not sure if that's realistic behavior or not though.

There was another post here about this switch ...  And a couple of the CRJ pilots said that they never turn it off....  so apparently it can be disconnected and connected with the switch left in the "enable" position....

 

Think one said it was like... "Gets turned on in the morning with the first flight of the day and then Turned off at the End of the Day after the last flight and shutting down all power to the plane.." something like that..

[Tbo 7]

I think I got it, I never turn it off I thought it would turn off automatically When GPU is disconnected.

[LesOReilly 314]

I have it on a "switch" on my Saitek Panel so that has very obvious "On and Off" locations

 

 

[Puuhbear 114]

You can actually tell if the button is pushed in (activated) or pushed out (deactivated) if you look really closely. 

[Crabby 28]

On 9/2/2021 at 3:47 PM, Tbo said:

Hi,

 

When I arrive on stand I experience the following behavior:

 

- Blocks on wheels

- GPU is connected

- I get "green" available light but I can't switch it on / push on active. Nothing happens.

- I need to switch off APU first but I loose all electrical

- Only then I can switch on the electrical and everything is coming back, but sounds odd? Or is it normal?

 

Thanks

If the GPU button is pushed in, it will show as AVAIL while the APU is running.  This is because of the hierarchy of the system.  1. Engine generators, 2. APU, 3. GPU.  If ground power is connected AND the light show AVAIL AND is pushed in, the system will automatically cut to it when the APU is powered off.  

 

To reiterate, as long as the APU is running, the Ground power will show as AVAIL even if pushed in until the APU is shut down.  

1. Taxi to gate

2. Set chocks

3. Connect Ground Power AND Push the Button

4. Turn off APU

5. Ground Power takes over automatically.

 

As mentioned above, once you push the ground power button at the beginning of a days flight, just don't touch it again until you have to secure the cockpit.  No reason to "turn it off". 

[Tbo 7]

Thanks I got it