A330 sinks have drain valve that negates any air flow out regardless of sink plug position. It will only open when liquid flows and shuts automatically when fluid stops.

GP

If I recall, and I may not, this is a common Airbus problem and is Maintenance related.
I'm sure it is in the TSM but not as "Flight deck stinks of poo !"
It's a Ducts/Fan/Filter clean issue.

Lav?galley extraction fan
 

I'm a boeing man myself. The 747-400 has 2 Lav/galley extraction fans with one running at any time to remove toilet and galley odours. If both fail its a no go.
The A320 has a single Lav/galley extraction fan. What the A330 has I don't know but I would expect it to have something similar.

When the smells come into the flight deck they seem to be coming from the avionics compartment. The eyeball vent fresh air is not smelly and is a life saver at the time. I dont think the smells come through the door. So the airconditioning system must be circulating the smell from the extraction fan into the avionics bay somehow??
I plan to write it up each time until it stops. (Still too naive.)

A good maintenance practice to clean the toilets pipes and the smell is to get a bucket of crashed ice (7-10 mm diameter ) and about 10 litres of vinegar and flush it down the toilet. then service the waste tank. its a good idea to check the pipe work near the toilet as well.

Well, at least we're getting gassed by first class poo! :ok:

Unlikely that the duct will be blocked, more likely clogged or duct is collapsed from being clogged for too long

GP

Clear the complaint!

If it's a leak it could be a threat to equipment nearby.

Maybe it's because the engineers are taking so much poo that they're used to the smell? :{

Replace the vent filters......

I work for an Australian airline that flies A330-2/300. We have experienced this issue and found air flows fwd from fwd lav into flight deck behind sidewall due to airflow issues. This is due to a restriction to the Lav vent extraction system. We have had the restrictor in the fwd lav extraction duct removed and this seems to solve the problem as there is now a greater airflow into extraction system with restrictor removed. Air is thus no longer moving fwd into flt deck but upwards into lav vent system. Our reports go back as far as 2003 and Airbus are aware of the issue. :ok:

How do you legally remove the restrictor from the exraction duct and operate this way? What do you use as documentation as approval?

has the aircraft been used on the Hajj ?

You can request an engineering authority to remedy the situation or be dircted by an engineering instruction from a techinical services area.