APU needles / meter

[s.mellah 7]

Hello,

 

Am I the only one having this problem with the lights not litten on certain buttons ? (smoking signs, GEN 1-2-3, AC1-2 APU buttons)

This lead me to another problem while using the aircraft. I could live without the passenger annonciator, but the other ones are pretty frustrating as it diminish the functions of all these complexe systems. For exemple,  I'm not sure my APU is working propelry. As I have no lights to confirm the GEN or the start is ON. I have to rely on the needle/meter. Starting the APU as mentioned in the manual, I only get the APU RPM % and GEN LOAD showing activity. I can see fuel burning, but as soon as I unselect EXTERNAL source power and come back to NORMAL (to be using APU source), the APU needles come to zéro. And I have no power in the aircraft. All in all I' can't make the APU work and I can't use certain modules lights. It is rather frustrating for such a well devloppe aircraft.

If anybody can help me figure it out, it would be greatly appreciated.

I'm using version 2.0B on P3d 4.5 and having the F35 as default aircraft on the menu.

 

Whish you all good health

Souheil

Edited May 3, 2020 by s.mellah

[ark 1,288]

3 hours ago, s.mellah said:

Hello,

 

Am I the only one having this problem with the lights not litten on certain buttons ? (smoking signs, GEN 1-2-3, AC1-2 APU buttons)

This lead me to another problem while using the aircraft. I could live without the passenger annonciator, but the other ones are pretty frustrating as it diminish the functions of all these complexe systems. For exemple,  I'm not sure my APU is working propelry. As I have no lights to confirm the GEN or the start is ON. I have to rely on the needle/meter. Starting the APU as mentioned in the manual, I only get the APU RPM % and GEN LOAD showing activity. I can see fuel burning, but as soon as I unselect EXTERNAL source power and come back to NORMAL (to be using APU source), the APU needles come to zéro. And I have no power in the aircraft. All in all I' can't make the APU work and I can't use certain modules lights. It is rather frustrating for such a well devloppe aircraft.

If anybody can help me figure it out, it would be greatly appreciated.

I'm using version 2.0B on P3d 4.5 and having the F35 as default aircraft on the menu.

 

Whish you all good health

Souheil

To see if it makes any difference, try starting the APU from All systems off without using a GPU by:

1. Put External Power switch in the NORMAL position.

2. Connect the A and B buses by turning the Flight Normal switch to off (horizontal position).

3. Turning on the battery switches on the overhead panel.

4. Turning on the #2 Booster switch (switch up).

5. Pushing the Master APU switch (leftmost button)

6. Pushing the APU Gen switch (middle button).

7. Pushing the APU Start button (next to APU Master button).

Al

 

Edited May 3, 2020 by ark

[Ariel 6]

I also have found that there is a problem with the APU start-up when the start switch is selected to External Power.  It won't work properly until the power switch is put back to the Normal setting.  I'm sure that you should be able to start the APU when connected to external power (a GPU) - but in the Falcon I have to switch to "Normal" internal power first.  If I don't, the APU sort of half starts but without the usual sound, as best I can remember.

Ariel

[ark 1,288]

21 minutes ago, Ariel said:

I also have found that there is a problem with the APU start-up when the start switch is selected to External Power.  It won't work properly until the power switch is put back to the Normal setting.

If I recall correctly the FSW manual specifically says the Start Selector switch has to be in the Normal position to start the APU.

Al

Edited May 4, 2020 by ark

[JRBarrett 3,038]

4 hours ago, ark said:

If I recall correctly the FSW manual specifically says the Start Selector switch has to be in the Normal position to start the APU.

Al

This is correct. In the real Falcon 50, you would not use the APU and an external GPU at the same time. The Falcon is not like an airliner, where it would be standard practice to run the aircraft from GPU power at the gate, start the APU before pushback, and then transfer power from the GPU to APU.

With the Falcon, the only time a GPU would typically be used on the ramp before departure would be in a situation where the APU is inoperative. In this case, with the GPU connected, you would use GPU power to start all three engines. Before engine start, all three generator switches must be on. The battery switches are turned on too, but the batteries will not actually come online until the external power switch is placed back to “Normal”, at which time the aircraft power will smoothly switch to the generators. The GPU can then be disconnected.

It’s different with the Lear 35, which has no APU. Lear operators normally try to arrange for a GPU for every engine start if possible, as it saves a lot of wear and tear on the batteries,

In the Falcon, the APU is always the preferred power source prior to, and during engine start. The DC power supplied by the APU generator is cleaner and better regulated than what is supplied by most GPUs, and on a hot or cold day, you would need to run the APU so bleed air would be available for the packs. Also, when starting engines using APU power, the batteries come online during the start cycle to provide voltage and current assist.

BTW, I don’t know if the FSW checklist mentions this, but it is standard practice to turn the APU bleed valve off just before engine start, (if it was being used for air conditioning), otherwise the APU EGT might over-temp when the engine starter is engaged. That is probably not modeled in the FSW Falcon.

If the APU is inop, and no GPU is available, it is possible to start engines on battery power alone, but it’s not something one would want to do unless absolutely necessary. The batteries need to be in tip-top condition, and after the first engine is started, the pilot needs to wait until the battery fully recharges before trying to start the second engine, or it is easy to blow the bus tie current limiter. The engine generators will then assist the batteries when starting the third engine.

TL:DR  If you are able to use the APU to power the aircraft before start, you would not have a GPU connected in the first place. The GPU is used primarily to power aircraft systems on the ramp or hangar for maintenance, or on those occasions where the APU is inoperative.

Edited May 5, 2020 by JRBarrett

[ark 1,288]

56 minutes ago, JRBarrett said:

This is correct. In the real Falcon 50, you would not use the APU and an external GPU at the same time. The Falcon is not like an airliner, where it would be standard practice to run the aircraft from GPU power at the gate, start the APU before pushback, and then transfer power from the GPU to APU.

..........

 

Jim,

Once again,  thanks for taking the time to share your expertise and experience.  Sincerely appreciated!

Al

Edited May 5, 2020 by ark

[s.mellah 7]

Thank you all for your explanations and solutions.

I followed Al's ckecklist and the APU work properly. As a matter of fact even the lights that were not functionning came to life.

Clearly I was doing it wrong by firts driving the GPU and then passing on the APU. I understand now that if one starts on the GPU, the APU will be unavaible later. Or at least on my side it goes like this. Strange fact is that it solves as well my light problem. Okay... I guess I'm all good now to enjoy the full potential of the systems thanks to you guys. 

Best.

Souheil