A 320 DC ESS BUS FAULT

[Jimmy Hoffa Rocks]

Have your aircraft been impacted by DU 00012511 on certain MSN

The implications are in case of DC ESS BUS FAULT the audio cards of the AMU are lost, since all cockpit mikes and headsets are connected to the AMU, all audio means of communication ( including VHF,HF and SATCOM ) are lost,

The use of VHF 2 or 3 do not allow to recover communications ( on these MSN ) , others yes.

Can Airbus correct this DU ?:confused: Through a electrical re wiring or service bulletin, so that one could recover communications bypassing the AMUs?

This DU just came out, so that means that it has been this for a while.

If anyone can shed some light on this, thanks in advance

[EGPFlyer]

It's been out for ages and there's a fix which is on newer aircraft and can be retrofitted.

[IFixPlanes]

It's been out for ages... Yes, since 08 Jun. 2007.


...and can be retrofitted ... with Modification No. 37782.

[Jimmy Hoffa Rocks]

Thanks for your help

How uncommon is a DC Ess bus fault on the A320 ? not nice to lose comms at same time

Has anyone actually had one or know of one ?

Interesting how you have to pull the fire handle to shut down the engine

[Natstrackalpha]

Why do people still insist on regarding a DC ESS fail with irrecoverable COMMs.

COMMS ARE recoverable as I have many times posted.

BA found a way and everybody followed suit.

Well almost everybody.

Its not in the FCOM or the AOM or in the QRH or on ECAM.

BA, when buying the then new A320 (and other a/c) got the engineering diagrams, as they do, and studied the whole thang in great detail, just to find out what could possibly be there that the manufacturer may have missed. DC Essential Failure is one of them. Hence, should there ever be a DC ESS fail on a BA flight, they will restore comms. Naturally, people tend to re-vamp it and claim it is their own creation.

[Magnetic Iron]

Nattracks,

how are comms recoverable with the audio cards of the AMU lost,? how would that work on these models ?

[tom775257]

Nattrackalpha... also I am interested in how to recover comms in the affected aircraft with DC ESS fail? Even Airbus say without the modification on the affected aircraft comms not recoverable. Is there a sneaky trick to get around this?

[Fursty Ferret]

Is there a sneaky trick to get around this?

Dropping the RAT should do the trick unless I'm mistaken.

[BlackandBrown]

A320 - ECAM - [12] DC Ess Bus Fault - YouTube

[EGPFlyer]

Natstrackalpha, perhaps you could enlighten us? :ok:

[tom775257]

FCOM verbatim from an affected aircraft:

In the case of an ELEC DC ESS BUS FAULT, the audio cards of the AMU are lost. Since all cockpit
mikes and headsets are connected to the AMU, all audio means of communication (VHF, HF and SATCOM )are lost.
The use of VHF 2 or 3 do not allow to recover communications.

Not sure how the RAT would help things if you have a bus fault?

[Fursty Ferret]

Tom - I was thinking of the case of the EasyJet A/C when they lost AC1, and consequently AC + DC ESS.

Haven't got the FCOM open in front of me, but depending on the failure it may be a fault elsewhere on the network. Dropping the RAT supplies the ESS network through the ESS TR, and on top of that sheds some of the bus anyway.

So it's possible that if the fault lies elsewhere, or only on one part of the bus, dropping the RAT may resupply the DC ESS bus. Or am I talking out of my arse? (Very possible!)

[tom775257]

Hi Fursty.

As always with Airbus the FCOM tells half the story so you may well be correct, but it doesn't sound right to me. The AMUs are powered by the DC ess 'main bus,' the DC ess shed bus doesn't power much of too much interest apart from wing anti ice. I would have thought with a shed bus fault it would just go ahead and shed itself! If the bus is shorted out I don't see how you could recover it.

What is obvious is that if we can even debate this, something is up with knowledge or training about this. If there is actually a way to recover communications in affected aircraft that haven't been retrofitted, there should damn well be an OEB about it until ECAM could be updated to reflect the new procedure or Ifixplanes proper fix can be done.

This only affects 3 aircraft in our fleet, but goddam, it is a good gotcha.
Cheers, Tom.

[Natstrackalpha]

You lost RMP 1 & 2 and ACP 1. Switch Audio to FO 3.

F/O tunes his/her Radio using RMP 2 on the overhead. Tuning VHF 2 or 3 (maybe a slight ACARS thang here but I digress).

Capt has nothing. Turn up loudspeaker to receive,
F/O tx using his/her sidestick trigger.
Capt tx using F/Os mike which is stretched--------------------------------------------------------------------------------------------behind the centre pedestal.
For INT ask F/O to move his/her headphone on their left ear or shout.

Make sure cabin door is closed if shouting about your last row with your ex.

(You won`t any the lights on the RMP (nor the acp either.)

[busav8r]

The video posted by BlackandBrown explains how to recover comms. This is an old video (produced by TAP Air Portugal training department I believe) and it is slightly outdated but it is well worth to watch it.

And Natstrackalpha also got it right.

During Ecam Actions we must use VHF2 on RMP2 for reception and ACP3 to communicate. For that select Audio Switching (on overhead panel) to CPT or F/O:
- if CPT position is selected > only CM1 will be able to hear + transmit using his/her headphones.
- if F/O position is selected (BEST OPTION) > F/O will be able to hear + transmit using his/her headphones and CM1 will be also able to hear comms via CM2's Loudspeaker.

After Ecam Actions are completed, it is recommended CM1 to be PF. This way CM2 has an easier access to RMP2 and ACP3, and CM1 can monitor communications through the right loudspeaker.

Comms with Cabin Crew it is only possible by using the Handset or via ACP3 (using PA). Cabin interphone is inop.

In relation to RAT extension, it doesn't help in this particular situation, unless we need to recover the Blue Hyd sys.

[Citation2]

Is ACP3 on A320 independently supplied or through the AMU via DC ESS bus?

Nice procedure to recover comms , but I wonder if it's still working on new aircrafts.
FCOM describes the AMU as the brain of communication and it states that ACP 3 works through the AMU.
Now with an AMU unserviceable or unpowered due to DC ESS BUS fault , I really doubt that ACP3 gonna be working.

[tom775257]

This whole thread is mixing up various versions of the A320.

1)There are A320s without digital AMUs that can be recovered as mentioned by Nattrackalpha and Busav8r - which I hope everyone knows about, basic stuff.

2)There are A320s with digital AMUs that will NOT have ANY functional VHF/HF/SATCOM/ACARS functional with DC ESS fail. No matter what switching you do! Here is a re-post of the FCOM ref above from an affected aircraft:

<<<In the case of an ELEC DC ESS BUS FAULT, the audio cards of the AMU are lost. Since all cockpit
mikes and headsets are connected to the AMU, all audio means of communication (VHF, HF and SATCOM )are lost.
The use of VHF 2 or 3 do not allow to recover communications.>>> In otherwords no matter what switching you do, you've lost them.

3)There are A320s with digital AMUs that from manufacture or retrofit will have comms capability with DC ESS FAIL using the usual method.

[tom775257]

From Airbus regarding the fix for these affected aircraft:

A318/A319/A320/A321 A/C fitted with digital AMU:
• SB A320-23-1283 (Mod. 31296)
• SB A320-23-1258 (Mod. 34669)
• SB A320-23-1310 (Mod. 36518)

In case of a DC essential Bus loss, the digital AMU is no longer powered.
Consequently all radio and cockpit PA communications are lost.

AMU power supply has been modified to keep communications means even in case of DC essential Bus loss (Mod. 37782):
- SB A320-23-1333

[Citation2]

Thanks for clarification

[busav8r]

Tom775257, thanks a lot for the explanation. I'm glad my company doesn't have any acft with those mods.

[Natstrackalpha]

Sorry guy n ladies, I scr:mad:d up.

I was looking at models which did not have the AMU. Sorry, for the suspense. Citation is right, and all the rest of you who mentioned this.

In fact I have not yet seen an AMU version.

[tom775257]

I think it is great that this has raised discussion, it has made myself and others think about this issue, no need for sorry my friend.