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Some Sort Of Smoke In Cabin While Acr On Ground  
User currently offlineA380CGN From Germany, joined May 2006, 21 posts, RR: 0
Posted (8 years 4 months 3 weeks 6 days 1 hour ago) and read 10578 times:

Hello everyone,
yesterday I was flying with 4U from CGN to VIE on an A319 and I noticed something I have never seen before and I don't know what it is: While the aircraft was on ground some sort of thick white smoke (which looked like evaporating dry ice) was constantly streaming out of the air conditioning outlets over the windows and over the overhead bins (but not out of the overhead air conditioning nozzles; only over the windows and over the bins). I held my hand in the smoke and noticed that it was pretty frosty. When the engines were started the smoke began streaming out more fast and when the engines spooled up for taxi there was even more smoke coming out. Only when we took off the smoke stopped.
As the F/As were quite busy I couldn't ask them about it but maybe you can help me...?
Thanx in advance for your answers  Smile

37 replies: All unread, showing first 25:
 
User currently offlineFr8Mech From United States of America, joined Sep 2005, 5654 posts, RR: 15
Reply 1, posted (8 years 4 months 3 weeks 6 days ago) and read 10594 times:

Was it humid out?

The 'smoke' was propbably condensation. Normal when the the conditions are hot and humid and the pacs are working their hardest to cool the cabin.



When seconds count...the police are minutes away.
User currently offlineXjramper From United States of America, joined Dec 2003, 2473 posts, RR: 51
Reply 2, posted (8 years 4 months 3 weeks 6 days ago) and read 10589 times:

Even when its a little bit hot out, that is the way the air conditioning works until it is in the air. Once airborne it uses the air at altitude to a/c the aircraft. I don't know how the A/C works, but perhaps MEL or someone could explain it better while the aircraft is on the ground.

XJR



Look ma' no hands!
User currently offlineBri2k1 From United States of America, joined Dec 2004, 988 posts, RR: 4
Reply 3, posted (8 years 4 months 3 weeks 6 days ago) and read 10587 times:

You can read my detailed post about air conditioners on jet powered aircraft here, in reply #2:

Dangerous Goods And Refrigerators On Aircraft (by Spinaltap Jul 24 2006 in Tech Ops)

The only difference on the ground is the APU provides the input air to the air cycle machines instead of the engine bleeds.

This "smoke" is definitely water vapor. It's pretty common on the A319/320/321 family while it's on the ground. I don't know why, but If I had to make a bet, it would be because the APU can't cool the air as much as the engines can, so water vapor that has frozen up during the flight melts when it lands and you see it entering the air stream.

[Edited 2006-07-28 22:38:26]


Position and hold
User currently offlineAvioniker From United States of America, joined Dec 2001, 1109 posts, RR: 11
Reply 4, posted (8 years 4 months 3 weeks 5 days 23 hours ago) and read 10565 times:

Before the new air cycle machines and water separators came into being I used to be able to make it snow in the cabin on a nice June Orlando afternoon.
AAAhhhhhhhhh the good old days...
 Smile



One may educate the ignorance from the unknowing but stupid is forever. Boswell; ca: 1533
User currently offlineJamie757 From , joined Dec 1969, posts, RR:
Reply 5, posted (8 years 4 months 3 weeks 5 days 23 hours ago) and read 10555 times:

Quoting Bri2k1 (Reply 3):
This "smoke" is definitely water vapor

I'd second that.

Quoting Bri2k1 (Reply 3):
It's pretty common on the A319/320/321 family while it's on the ground

I'd second that too, I've seen this happen a few times on the A321. Nothing to worry about.

Rgds.


User currently offlineNonfirm From United States of America, joined Sep 2005, 434 posts, RR: 0
Reply 6, posted (8 years 4 months 3 weeks 5 days 22 hours ago) and read 10536 times:

Quoting Bri2k1 (Reply 3):
It's pretty common on the A319/320/321 family while it's on the ground

Also very common on the MD-80 as well you can almost make it rain. airplane 


User currently offlineN8076U From United States of America, joined Jun 2006, 425 posts, RR: 9
Reply 7, posted (8 years 4 months 3 weeks 5 days 21 hours ago) and read 10522 times:

I remember when we were almost done with a C-check on an A320, they'd do a pressurization and pack operational/leak check, and you'd get that "white smoke" condensation from the vents then as well, even in a not so warm or humid environment at SFO.

Chris



Don't blame me, I don't work here...
User currently offlineMusapapaya From United Kingdom, joined Apr 2004, 1098 posts, RR: 0
Reply 8, posted (8 years 4 months 3 weeks 5 days 21 hours ago) and read 10509 times:

Quoting A380CGN (Thread starter):
Hello everyone,
yesterday I was flying with 4U from CGN to VIE on an A319

Hey there!
How was your flight then? Was it nice one? I am a supporter of 4U!
William



Lufthansa Group of Airlines
User currently offlineN600RR From United States of America, joined Feb 2006, 171 posts, RR: 0
Reply 9, posted (8 years 4 months 3 weeks 5 days 18 hours ago) and read 10486 times:

Quoting Bri2k1 (Reply 3):
This "smoke" is definitely water vapor. It's pretty common on the A319/320/321 family while it's on the ground.

...it happened in my Toyota truck yesterday morning.  cold  smile 

Quoting Avioniker (Reply 4):
Before the new air cycle machines and water separators came into being I used to be able to make it snow in the cabin on a nice June Orlando afternoon.
AAAhhhhhhhhh the good old days...

Would have liked to see that! Was it hard to do, or did you
just turn the a/c on when it was very humid?



"And the fluffy white lines that the airplane leaves behind are drifting right in front of the waning of the moon" -Cake
User currently offlineBohica From United States of America, joined Feb 2004, 2749 posts, RR: 0
Reply 10, posted (8 years 4 months 3 weeks 5 days 17 hours ago) and read 10483 times:

Quoting Fr8Mech (Reply 1):
The 'smoke' was propbably condensation. Normal when the the conditions are hot and humid and the pacs are working their hardest to cool the cabin.

The best part is watching the passengers get nervous.  Big grin


User currently offlineHAWK21M From India, joined Jan 2001, 31712 posts, RR: 56
Reply 11, posted (8 years 4 months 3 weeks 5 days 12 hours ago) and read 10460 times:

Thats caused by Water Vapour in the Conditioned Air.

The Packs have Water Seperators/Water Extractors in the System.Sometimes due to Coalaser bag blockage or Defective components,if the Water is not properly seperated from the Conditioned Air,this type of Smoky effect arises.

The Warmer outside Temperature contributes to the effect too.

regds
MEL



Think of the brighter side!
User currently offlineMD11Engineer From Germany, joined Oct 2003, 14139 posts, RR: 63
Reply 12, posted (8 years 4 months 3 weeks 5 days 11 hours ago) and read 10442 times:

Quoting Fr8Mech (Reply 1):
Was it humid out?

The 'smoke' was propbably condensation. Normal when the the conditions are hot and humid and the pacs are working their hardest to cool the cabin.

Hot and humid? Most of Europe was at 32-39 degrees centigrade (90-100 degrees Fahrenheit) with 60 to 80 % relative moisture during the last few days!

Jan


User currently offlineMatt72033 From United Kingdom, joined May 2005, 1617 posts, RR: 4
Reply 13, posted (8 years 4 months 3 weeks 5 days 10 hours ago) and read 10434 times:

happens on our 340's often!

i remember being sat on the ground at the gate at JFK last october, there was a huge storm going on outside and it happened to us then, my friend who i was travelling with turned to me and said "isn't it great how they do that? i remember when the hosties used to walk up and down the aisle spraying the pesticides, now they just do it through the vent system"

i've never laughed so much in my life!


User currently offlineJeb94 From United States of America, joined Oct 2004, 608 posts, RR: 4
Reply 14, posted (8 years 4 months 3 weeks 5 days 8 hours ago) and read 10422 times:

I first saw this on my first C-130 ride out of Okinawa. Not that uncommon and certainly not unsafe.

User currently offlineA380CGN From Germany, joined May 2006, 21 posts, RR: 0
Reply 15, posted (8 years 4 months 3 weeks 5 days 6 hours ago) and read 10408 times:

Hey everyone,
thanks a lot for your answers!  Smile I already thought, that it was nothing to worry about but I just hadn't seen this before. Thanks again.

Quoting Musapapaya (Reply 8):
Hey there!
How was your flight then? Was it nice one? I am a supporter of 4U!
William

Yeah, it was quite nice. I did that as a day-trip. In the morning I flew on the D-AKNR with the former US-Airways interior and on the way back it was the brand new D-AGWA. The seat pitch is quite narrow but for me it's okay.  Smile


User currently offlineZeke From Hong Kong, joined Dec 2006, 9229 posts, RR: 76
Reply 16, posted (8 years 4 months 3 weeks 5 days 6 hours ago) and read 10401 times:

Quoting Bri2k1 (Reply 3):
This "smoke" is definitely water vapor. It's pretty common on the A319/320/321 family while it's on the ground. I don't know why, but If I had to make a bet, it would be because the APU can't cool the air as much as the engines can, so water vapor that has frozen up during the flight melts when it lands and you see it entering the air stream.

Packs fed by the APU or high pressure external bleed are on high flow on the ground regardless of the setting on the overhead panel, with the engines supplying the bleed the pack flow reverts back to the setting on the overhead panel, usually "norm".

The condensation is also a function of the air that is in the cabin at the time, usual only to see this at the start of a flight, at the end of a flight when the environment inside the cabin stabilised during the flight you will not see the marked change in relative humidity between the air in the cabin and that being supplied by the packs.



We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
User currently offlineTristarSteve From Sweden, joined Nov 2005, 4068 posts, RR: 33
Reply 17, posted (8 years 4 months 3 weeks 5 days ago) and read 10362 times:

The good old Vickers VC10 had godfrey blowers instead of packs. These worked well but were not very good at extracting the water.
On a descent into BAH at night where it is 30degC and 100% humidity ( yes I mean 100%, you needed windscreen wipers on to drive your car!), when the aircraft pitches nose up on finals the last four seat rows of pax get a shower!. You only sit there once!


User currently offlineN231YE From , joined Dec 1969, posts, RR:
Reply 18, posted (8 years 4 months 3 weeks 4 days 20 hours ago) and read 10335 times:

I've noticed it on Avro RJ85's, coming out of the vents above the windows. Interestingly enough, while many A.Netters are talking about APU's and engine bleed air, the Avro that I experienced this on was hooked up to a ground mounted air-conditioning unit.

User currently offlineRichPhitzwell From , joined Dec 1969, posts, RR:
Reply 19, posted (8 years 4 months 3 weeks 4 days 16 hours ago) and read 10318 times:

Quoting N600RR (Reply 9):
Quoting Bri2k1 (Reply 3):
This "smoke" is definitely water vapor. It's pretty common on the A319/320/321 family while it's on the ground.

...it happened in my Toyota truck yesterday morning.

You beat me to it, I used to have a Toy and it did this every now and then. freaked me out the first time as I was driving down the freeway. Never had any other truck do this.

I can imagine how worried PAX would be. Im suprised nobody screamed fire.

[Edited 2006-07-30 06:13:51]

User currently offlineHAWK21M From India, joined Jan 2001, 31712 posts, RR: 56
Reply 20, posted (8 years 4 months 3 weeks 4 days 14 hours ago) and read 10307 times:

On the B737 Freighters,its common to notice this Smoke effect on Ground.
With The Main Deck lined with Smoke picups leading to Photoelectric type Smoke Detectors.Often the Thought is when would a Smoke Warning Illuminate,Luckily the Fogged Air does not continue to the Detectors as smoke would  Smile but the thought is always there.
regds
MEL



Think of the brighter side!
User currently offlineBri2k1 From United States of America, joined Dec 2004, 988 posts, RR: 4
Reply 21, posted (8 years 4 months 3 weeks 1 day 11 hours ago) and read 10210 times:

I rode on a UA 744 today and it there was so much mist, one passenger called it the "halloween flight." I took a short video. I'll see if it can get posted on another aviation forum which allows videos instead of just photos and provide a link here.


Position and hold
User currently offlineHAWK21M From India, joined Jan 2001, 31712 posts, RR: 56
Reply 22, posted (8 years 4 months 3 weeks 1 day 10 hours ago) and read 10202 times:

Quoting Bri2k1 (Reply 21):

Was this Mist In flight or on Ground.Looking fwd to the Video. Smile
regds
MEL



Think of the brighter side!
User currently offlineBri2k1 From United States of America, joined Dec 2004, 988 posts, RR: 4
Reply 23, posted (8 years 4 months 3 weeks 1 day 6 hours ago) and read 10186 times:

It was only on the ground.

They tried to start number 4 engine first, but the start valve would not open. The entire time the packs were running from the APU, it was just pouring out of the vents. We had to wait a while for a mech to manually open the start valve. As soon as a couple engines were running and the packs were running from bleed air, it instantly stopped misting. I'm talking now. This is consistent with all of my previous observations and is the reason I'm skeptical about the explanation given for why it happens on the ground but not in flight.

Strangely, there was no air coming out of the directional nozzles in the overheads until about half way through the 2-1/2 hour flight (ORD-DEN). Somewhere over Nebraska, they all of a sudden came on full bore. When we got to DEN there was a ground hold due to lightning and we had to wait about 25 minutes before we could be marshalled into the gate. Because of the delay, I had to rush off the plane and didn't get a chance to ask about it. When we got to DEN, which was clearly more humid than ORD on account of the thunderstorm, the mist did not start back up. I didn't see if the plane was hooked up to a ground-based air source. I know the same plane was going to continue to SFO a couple hours later, but they could have run the APU the whole time I suppose.



Position and hold
User currently offlineBri2k1 From United States of America, joined Dec 2004, 988 posts, RR: 4
Reply 24, posted (8 years 4 months 3 weeks 1 day 5 hours ago) and read 10177 times:

OK, here it is:

http://video.google.com/videoplay?docid=919287952559647513



Position and hold
25 AC320tech : it happens quite frequently on the Airbus A320 family, about 1/4 of the 320 family fights I have been on have this issue, and its more common in the s
26 HAWK21M : Nice Video.What Recorder did you use. regds MEL
27 Bri2k1 : I have a Sony DSC-T5 digital still camera that also takes short video clips. I have a 1GB Memory Stick Duo Pro for it, so I think I can record 350 hig
28 HAWK21M : Im sure all do.After all you are sharing it & thats Appreciated.Any other Good ones. regds MEL
29 113312 : Thank goodness it's not evaporating "dry Ice" which is carbon dioxide and not conducive to life! As most everyone has pointed out, the vapor is harmle
30 Usair320 : Im gonna say condensation from the air conditioning unit.
31 ThirtyEcho : Sheesh, folks, it is WATER VAPOR from the air condtioning system. It was particularly noticeable on the Convair 240s in south Loisiana in the summer.
32 Usair320 : Technically condensation and Water vapor are similar although not exactly the same.
33 HAWK21M : Don't Ground AC Units have Water Seperatrs/Extractors. regds MEL
34 Zeke : Incorrect. It is the "new cool air" entering the cabin cooling the air in the cabin to the dew point temperature forming fog, this is then heated by
35 Bri2k1 : Perfect example. Boil some water on the stove so the humidity goes up in the kitchen, then open the kitchen. In the days before I had a seperate brew
36 Post contains links HAWK21M : Condensation:- The physical process by which a vapor becomes a liquid or solid; the opposite to evaporation. In meteorological usage, this term is ap
37 Post contains images N600RR : " target=_blank>http://nsidc.org/arcticmet/glossary/ Interesting... What about this definition (from same site): Hydrometeor Any product of condensati
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