A320 Elec Emer Config

[Cak]

Few years back, many guys used to fly during night with cockpit dome light in DIM position and the explanation was that the right dome light will stay on in case of Emer Elec Config as the only light available in cockpit except left side instruments.
2 or 3 years ago few TREs told me that Airbus changed switching and that right dome light will go on in case of Elec Emer even if the switch is set to OFF.
I remembered that and I was trying to find the reference, but unsuccesfully. Just because I don't like to have it on during night because it is too bright for me.
I know that it is connected to DC Ess Bus but does anybody knows for sure does it have to be in DIM or BRIGHT position to have it in Emer or does it really lights up automatically?

[Bus Driver Man]

Check the Normal SOP section in the FCOM.
It should be written in the preliminary cockpit preparation section whether or not you should keep the dome light in dim for take-off.

This was written in the 2012 FCOM version:
DOME light should be on because it is the only lighting source in the EMER ELEC configuration. The DIM position is recommended for takeoff.

If this isn't written in the current FCOM, it's no longer required.

[Metro man]

Also an MEL item, no go if the light is U/S.

[Cak]

I know that it has been in FCOM before and I know that it isn't anymore.
But I am trying to find reference does it turns on automatically regardless of switch position or not.

[mikedreamer787]

Check the latest FCOM Vol 1 under LIGHTS and check your MSNs.

[Willie Nelson]

Hey Cak,

There used to be a Temporary Revision that required it to be on at least dim for takeoff, I can confirm that this is no longer the case.

[Dan Winterland]

That was because there was a fault with the supply to the internal lighting of the standby instruments if ISIS wasn't fitted. Now re-wired.

[Microburst2002]

Try to find it at the "mods", the list of modifications. Those many pages where all the modifications are recorded since the first A320. For instance, you can find there the modification that makes the switching of AC BUS ESSential to the AC BUS 2 automatic. Before you had to do it manually, remember?

It can be difficult to find it, but it must be there.

[mr.newfy]

these mods were carried out in service under service bulletins, SB A320-33-1057 and A320-24-1120.
the reasons given, "Some operators have reported occurrences of loss of the AC BUS 1 with subsequent loss of the AC ESS BUS and DC ESS BUS resulting in the loss
of 5 upper Display Units and the loss of integral lighting. In this situation flight
crew have reported concerns in reading the standby instruments when the
DOME lights were selected to OFF.
This situation, if not corrected, could increase the workload of the flight crew
which constitutes an unsafe condition.
This Airworthiness Directive (AD) mandates the modification of the electrical
supply logic by adding a back-up supply on the battery hot bus for the under
glare shield flood lighting."
and
"Several occurrences of loss of the AC BUS 1 have been reported which
led in some instances to the loss of the AC ESS BUS and DC ESS BUS
and connected systems. The affected systems include multiple flight deck
Display Units (Primary Flight Display, Navigation Display and Upper
Electronic Centralised Aircraft Monitoring display).
The reasons for these events have been investigated but have not been
fully established for all cases.
Due to the range of system losses some crews reported difficulty in
establishing the failure cause during the events and, consequently, the
appropriate actions to be taken may not be completed in a timely manner.
The loss of multiple display units, if not corrected expediently during a high
workload period, potentially affects the capability of the flight crew and
could contribute to a loss of situational awareness and consequent control of the aeroplane, which would constitute an unsafe condition.
This AD therefore mandates the modification of the electrical network
configuration management logic consisting in adding an automatic
switching of the AC and DC ESS BUS power supply such that upon the
loss of the AC BUS 1, the AC BUS 2 will automatically take over the
power supply. On pre-MOD aeroplanes, this power supply switching can
only be accomplished manually from the cockpit and is covered by an
Electronic Centralized Aircraft Monitoring (ECAM) procedure."

[vilas]

I checked in 1.8 std. Simulator and the dome light needs to be on to come on. The MOD mentioned does not say anything about dome light.

[Cak]

Thanks guys!
I would try that on the sim but I won't have opportunity for another 2, 3 months :)
I thought that the switch should be on but for some things it is almost impossible to find a real reference

[FlightDetent]

Cak, I recollect the same as Dan Winterland posted. This DIM position was required to overcome loss of internal lighting in conventional standby instruments.
- this was never an issue with ISIS
- the affected aircraft should have been rewired about 6 years ago.

Hence the DIM position not applicable or no longer required.

The other explanation suggested - auto dome light in OFF position - sounds very unlikely :E to me.

[Togue]

mr.newfy,


Great post.


I found the modification 24-1120-04 on PLP-LOM P 23/26 18 MAR
That reads:


Electrical Power - AC Essential Generation Switching - Install auto switching system for AC and DC ESS BUS


I couldn't find SB A320-33-1057. I would like to know what is it about.