Jet venting liquid overboard.

[ABX]

Hello All,

Was paxing in an A320 yesterday between Hobart and Melbourne and musing about some of the jets I have flown in (as pax only) and this thought bounced around my head for a while:

Do big jets vent any liquid while in flight? Do they for example vent the water from the hand basins overboard?

The reason for the question is simply because I imagine aircraft performance would be improved slightly as weight is jettisoned overboard?

Cheers.

[Intruder]

Yes, the sink drains vent overboard.

[ABX]

Thanks Intruder,

I thought that must be the case, as the staff don't like anyone going to the toilet while the aircraft is on the ground - yesterday they became very insistent that some poor sod return to his seat during boarding and not use the loo while on ground.

Do RPT aircraft vent any other liquids overboard during flight?

Thanks again mate.

Cheers.

[7FF]

Any fluids dumped into the sinks either in the toilets or galleys is jetissoned overboard. A far as I am aware, in normal operations, thats it.

[ABX]

What is the reason for venting sink fluids overboard instead of sending them to the sewer holding tank?

Is it as I suppose because sink waste is relatively clean and easy to dispose of (may evaporate or break up before hitting the ground) and will deliver minor performance gains?

Cheers.

[spannersatcx]

yesterday they became very insistent that some poor sod return to his seat during boarding and not use the loo while on ground

Unless it's a security thing, as I see no reason why toilets can not be used otherwise, we certainly don't stop there use.

Anyway I bet the CC were pouring liquid down the sinks in the galleys, which ends up in the same place as hand basin water.

[PENKO]

As said above, the water gets drained out through drainpipes under the aircraft. On windy days this drained water will get spraid into the faces of the ramp personell. Maybe that's the reason...

[ABX]

Where does the waste fluid exit the aircraft? I imagine underneath and to the rear?

[Rainboe]

It was to get the buggers to sit down and not disrupt the loading process by trying to move forward back to his seat agaisnst the flow of people boarding, and to ensure should there need to be a head count he was included.

Sink fluids are vented overboard from heated mast projections. Not for economy, weight loss is negligible. Toilet drain wagons remove all other waste. It costs. Why unnecessarily add a lot more relatively clean fluid to it?

[zerozero]

Space savings too.

I agree there is no weight issue but as with everything else in airplane design, physical space and capacity can become critical issues.

Why take up space in the toilet tank with soapy water and old coffee? Better to jettison that stuff and save the space for the real vile stuff.

ABX--sounds like the cabin crew were just being snooty about using the lavs on the ground and getting in their way. They can be like that.

True, the sink liquids get drained out of a heated mast. On the ground they just drain on to the ramp. In flight, at *very* cold temperatures, most likely, it vaporizes.

[Brian Abraham]

How much water is carried? Imagine a 747 long haul its quite a bit and not an insignificant percentage of gross.

[mitzy69]

sink drains

I believe the Comet had sinks basins draining into a tank, and was emptied on the ground like the toilet waste.
Water potable can be 1 ton, 1000 litres, on B747 B777.

[NutLoose]

ABX

Where does the waste fluid exit the aircraft? I imagine underneath and to the rear?

This picture shows you the drains, the HOT is because they are heated inflight to stop them freezing up and blocking

http://www.b737.org.uk/whiteice.htm

you will also find a lot more of interest on the site, please visit www.b737.org.uk

[Rainboe]

Now here's a big secret in aviation nobody tells you: into the toilets you throw blue sterising tablets to make the lavatory water a pretty shade of blue. Sometimes (actually quite often), the valve underneath the aeroplane where the toilets get emptied (a large pipe behind a hinged panel) leaks inflight. It works its way out of the panel (not airtight), and promptly freezes as it builds up. Eventually when the vibration loosens it, or it starts melting during descent, this rather large block of ice breaks off and falls away. It always seems to fall onto some Granny's house, burst through their ceiling and sit on their carpet. Granny is mightily impressed that this large pretty blue block of ice has fallen from the sky, and thinks it had better be kept for study by someone, so what does she do? She puts it in a large polythene bag, sometimes that one that her coat came back from the dry cleaners in if it's too big, and puts it in her freezer! In aviation, we have a term for this- a nice pretty name......Blue Ice. Google it if you don't believe me.

[aw8565]

Does this make you feel guilty Rainboe!?

http://uk.youtube.com/watch?v=czvF3HfJTLQ

[Rainboe]

"I never had nuthn' like this happen to ma in my whole life!"........er yes, one sincerely hopes one doesn't attract large 50 pound blocks of frozen sewerage falling on one's head more than once in a lifetime!

Couldn't stop laughing at the naivety of everyone! Er...yes....I feel sincerely guilty!

[ABX]

Great link NutLoose, that website is an interesting read.

[forget]

This'll take Rainboe's mind off Blue Ice.

[ABX]

Can anyone give me the fresh water capacity of their current aircraft?

For example, the A320 I was paxing on last Sunday would only hold a couple of hundred liters or so would it not?

Cheers

[Wodrick]

Good guess ! Potable water tank capacity A320 200 Ltr