'MAIN BAT DISCH' flickering after ELEC AC BUS R failure and Landing

[19AB67 16]

Hi captains, 

 

during my flight ACA34 YSSY--CYVR the ELEC AC BUS R failure occurred with all its accompanying stuff, eg. 

MAIN BATTERY DISCH

HYD PRESS PRI C2

NO LAND3. 

 

After landing I connected the ground power (the APU could not be started). 

Since then I see the MAIN BATTERY DISCH message flickering on and off quickly. 

Will it stop? When?

Or how can the main battery be charged (if the flickering shows any failure; however: No further failures are active anymore after some maintenance...)?

 

What's going on? 

 

Thank you. 

 

Edit, add-on: After dinner (1h50m) it is still flickering. So what does the main battery charge again? 

Edited May 2, 2014 by 19AB67

[Alpha Floor 237]

I'm not sure, but I think a single AC bus failing shouldn't cause the battery to discharge and the APU should still be usable.

 

Did you follow the electronic checklist?

[19AB67 16]

Yes, I did during my flight. It reads. 

1. Attempt only one reset: R GEN CTRL switch Off, then ON.

Check! 

2. ELEC AC BUS message blanks:

NO! 

3. APU selector (if APU available) START, then ON

Check! 

4. When the APU is running: ELEC AC BUS message blanks:  

NO!

5. Attempt only one one reset. R BUS TIE switch Off, then AUTO  

Check!  

6. ELEC AC BUS message blanks: 

NO! 

 

Inhibit checklists: WINDOW HEAT; HYD PRESS PRI C2. 

End of checklist. 

 

So, I continued my flight with the fault messages above, ie. also MAIN BATTERY DISCH. 

 

Now, I am savely on the ground, but I don't know, how to charge the battery. 

 

N.B.

A. During the flight I switched the APU off (extra fuel flow, and I am not sure whether it really works above a certain FL; also the APU did not help to blank the message). 

B. I wonder why the checklist does not suggest to utilise the RAM turbine as back up? ... or the AIR C1/2 driven backups? 

C. As the flickering does not stop (now after 5h on the ground) I switch on the engines as another ELEC power source.

Now the flickering continues but with the little square in front of it, meaning I shall consult the checklist again, but this one only notifies me about the very fact (Condition..., Note...) without any advice to do something about it. 

D. (Edit) Also switching off the battery switch does not change anything: MAIN BAT DISCH flickering. 

 

Have I found a little bug, or is it the true system behaviour? But how to charge the main battery after ELEC AC BUS R? 

Edited May 2, 2014 by 19AB67

[777simmer 117]

Yes, follow the ECL!

 

 

But you landed, correct....?

And you cleared the failures via the FMC, right?

 

And you still have problems?

 

I would say, something is preventing it from clearing all failures.

 

Why dont you just end FSX and restart a new flight?

I mean we can go digging into the system (which is pretty complex)....but if it is a PMDG777 little one time bug.....then why bother?

 

- The APU can be used for electrical purpose up to the 777 max certified altitude (43100ft)

- you should not have turned it off.

- with the 777, if a checklist sais to do something, you do it....dont do things it does not say.....do not start thinking, lol

- the RAM air turbine can not be pulled back in and causes drag, it is a last resort type of thing.

 

just end the flight.....you cant fix this.

Even the real airplane has to be made cold and dark sometimes (reset) for some problems to clear.

 

Have had that several times.....real nice after you have just done your complete FMC programming ;-)

[willywonka 36]

 

 

Have had that several times.....real nice after you have just done your complete FMC programming ;-)

That sounds interesting. What kind of problem did you have requiring a complete shut down?

[777simmer 117]

I am sorry, I really cant remember :-(.....too long ago.

 

Has not happened in the last, oooh...5 years or so.

[19AB67 16]

Hi Rob. 

 

 

 

But you landed, correct....?
And you cleared the failures via the FMC, right?

And you still have problems?

I would say, something is preventing it from clearing all failures.

Why dont you just end FSX and restart a new flight?

 

I mean we can go digging into the system (which is pretty complex)....but if it is a PMDG777 little one time bug.....then why bother?

 

Yes. 

Yes. 

Yes. 

Ok. 

Because I'd like to learn on how to charge the main battery, if it *is* the real behaviour. 

If it is not real, I do so. 

 

 

 

- The APU can be used for electrical purpose up to the 777 max certified altitude (43100ft)
- you should not have turned it off.

 

If it does not clear the message, the APU does not help, but only consumes my precious fuel... 

 

 

 

- with the 777, if a checklist sais to do something, you do it....dont do things it does not say.....do not start thinking, lol

 

Hhmm, is this the reason why it is better that I am not a real pilot? 

 

 

 

just end the flight.....you cant fix this.

 

Done. Reset. Check. 

 

 

 

Even the real airplane has to be made cold and dark sometimes (reset) for some problems to clear.

 

Interesting. As we say also re. our PCs: Reboot does good (Actually from the German saying: 'Reboot tut gut.'   8^)

 

Thanx. CU. 

[FLEX1978 373]

If you are a regular passenger you will likely see a reboot every now and then.  I fly about 4 times a month, last time the crew shut everything down and restarted was only a month ago.  

 

Just like any other modern machine, the good ol turn it off then on again often clears glitches!  

[777simmer 117]

Hi Rob. 

1) If it does not clear the message, the APU does not help, but only consumes my precious fuel... 

 

 

 

2) Hhmm, is this the reason why it is better that I am not a real pilot? 

 

 

3)Reboot tut gut.'   8^)

 

Thanx. CU.

 

1) You wrote correctly that if you can not correct the situation according the ECL, then it ends with:

6. ELEC AC BUS message blanks:

NO!

 

At that point the checklist ends.

You are left with an unpowered Main AC Bus.

 

It does not say "turn APU off"!

 

The reason for that is that in the background the APU is doing its job powering all kinds of things. Some are just backup functions, other functions do not become apparant untill the system want to switch on but can not. (because you turned the APU off).

The APU could also be powering hydraulic pumps that are activated upon extending the gear or flaps.

The 777 systems are way to complex to start second guessing the ECL, thrust me.

 

Another little example...how I learned not to do things the checklist does not say:

After an engine failure (with center tank empty) you are running both engines on one main fuel tank.

Thus creating a fuel imbalance.

So you do the fuel imbalance checklist and then you are cross feeding the operating engine from the fuller fuel tank.

What if you land before the fuel is balanced?

On every twin airplane I have ever flown.....you have to stop cross feeding before landing.....fuel selector back to normal!

So on one of my typerating flights I went to turn cross feeding off on final approach.......and I was then explained by the instructor......"dont do things that are not in the ECL"

On the 777 you can land (and go around) while cross feeding!

 

There are many examples like this.

 

The only case where you have to start thinking and puzzeling is when you have multiple failures and have to find the best out of several checklist.

(kinda like that Quantas A380 crew had to do after their catastrophic engine failure)

 

2) Yep you are way to smart to be a pilot ;-)

 

3) Jawohl

[DaveCT2003 1,820]

 

 

Because I'd like to learn on how to charge the main battery, if it *is* the real behaviour.

 

Because I'd like to learn on how to charge the main battery, if it *is* the real behaviour.

 

 

Excellent!  Bravo Zulu!

[19AB67 16]

 

 

2) Yep you are way to smart to be a pilot ;-)

 

That's what you said... 8^)

 

 

 

3) Jawohl

 

Don't mention the war!   8^)