A/c train
Topic Author
Posts: 674
Joined: Sun Jun 10, 2001 7:57 am

Blue ICE

Wed Apr 11, 2001 2:21 am

What is this blue ice I keep on hearing about, it went through a roof on the approach to Luton I heard, were is it leaking from? it must be a valve leaking or something , can someone tell me were and what the blue ice is and what system it goes into, my GUESS!!! is water tank but not sure,
Mr Spaceman
Posts: 2723
Joined: Thu Mar 15, 2001 5:09 am

RE: Blue ICE

Wed Apr 11, 2001 2:33 am

Hi A/c train. The first thing that comes to my mind is the lavatory. The "Dis-infectant Chemical" that is added to the water supply for the toilets is "Blue", and smells like bubble gum. If an airliner is leaking water from the Lav or even "dumpping" the Lav, I'm sure the water would freeze at altitude, and be a blue colour. Thus..."Blue Ice"

"Just a minute while I re-invent myself"
Mr Spaceman
Posts: 2723
Joined: Thu Mar 15, 2001 5:09 am

RE: Blue ICE

Wed Apr 11, 2001 2:43 am

I have read that if the "Tail Skid" fails to retract on a B-727 after takeoff, then the pilots have to shut down the AFT Lav and close the valves which alow water to exit the tail in front of the skid. If this isn't done, then water exiting from the Rear Lavs will form a nice chunk of "Ice" around the tail skid. Once the 727 decends into warmer air while on approach, the chunk of ice simply melts off and falls away to who knows where? Maybe your roof!

"Just a minute while I re-invent myself"
Posts: 495
Joined: Tue Oct 24, 2000 1:10 pm

RE: Blue ICE

Wed Apr 11, 2001 2:49 am

It's blue water leaking out of the dump chute of the waste tanks.

Most tanks have a valve at the top of the chute, a seal at the bottom known as the lav donut, and a cap at the end. In normal servicing, the lav driver opens the cap, attaches the hose from his truck. The hose has provisions to remove and install the donut while it's connected to the aircraft. Once this is done, there's a pull handle that opens the dump valve at the top of the chute that allows the contents of the tank to gravity drain in to the truck.

If any of these components fail, it could cause a leak, but what normally happens is that the driver forgets to re-install the donut, meaning that the dump valve and the cap are the only sealing elements. If the dump valve sticks open for some reason, the cap at has the entire job of keeping the fluid in the tank. This also results in a nasty surprise for the next lav driver. The next time you hear someone say that there is a whole school of "brown trout" under the aircraft, you'll know what they mean.  Big grin

Worst case scenario is a leak that results in a large chunk of ice that breaks loose when its mass gets large enough and causes damage to the aircraft or things on the ground below it.

Posts: 129
Joined: Thu Dec 30, 1999 7:41 am

RE: Blue ICE

Wed Apr 11, 2001 2:50 am

there's stories around on good old 727 losing blue ice slumps because old toilet systems leak overbord in flight. that comes off during descent / landing and can eventually go into an engine .. this blue ice stinks.

don't know whether all that's true.

you might also have "blue ice" in special, rare icing condition. It's ice building up quite fast on non- de-iced supercold surfaces and reach thick layers. This also comes off in descent. It looks transparent blue ... and does not smell at all.

 Smile/happy/getting dizzy
Mr Spaceman
Posts: 2723
Joined: Thu Mar 15, 2001 5:09 am

RE: 242

Wed Apr 11, 2001 3:27 am

Ha Ha! 242. Been there-done that! I know all about that special "Surprise!!!" your talking about. Years ago when I worked on a ramp with DASH-8's, many times, who ever's turn it was to "Dump the Lav" didn't know that the valve "PUCK" was not in place untill it was to late. Nothing like a soaking wet uniform!

What you called the Donut, we called the Puck [what do you expect from a bunch of Canadians Eh!]

However, sometimes we were lucky. If the Puck was accidently stuck in the "Honey Bucket" back at the point of departure, and the main Cap was leaking the Lav fluid really bad, you were WARNED by the "Blue Streak" that was smeared the whole length of the aircraft, from behind and under the Co-Pilot's window, all the way back to the tail! What a site, but a good Warning!!

"Just a minute while I re-invent myself"

RE: Blue ICE

Wed Apr 11, 2001 3:51 am

I was taught that there are two things you should never eat - blue ice and yellow snow.  Big grin

RE: Blue ICE

Wed Apr 11, 2001 4:53 am

Blue ice is from defective lavatory holding tank seals. The blue color is the deodorizer added to the water when the tank is serviced. Common causes are defective fill/flush line check valves and leaking dump valves. Although secondary protection such as the donut, as metioned above,(sometimes a dual sealing dump line cap) or fill line cap should prevent leakage. A common maintenance check is to fill the lav tank above the toilet bowl level, pressurize the aircraft and watch for leaks at the service panel. A vacuum tank is also available that fits agaist the fuselage and has a viewing glass. Blue ice is a serious and potentially dangerous problem. Large chunks of ice have gone through the roofs of homes, or caused major engine damage.
Posts: 91
Joined: Tue Mar 13, 2001 8:03 pm

RE: Blue ICE

Wed Apr 11, 2001 7:15 am

blue ice comes from the bogs, it is leaking usually from the release valve(as they never seem to close properly from my experience). It is a mixture of the toilet chemical and the contents of the waste tank. As it leaks at altitude it freezes in the extreme cold and as it thaws, usually on aproach it falls off, so if you see it dont touch it!!
Posts: 11191
Joined: Tue Jun 15, 1999 11:29 am

RE: Blue ICE

Wed Apr 11, 2001 7:31 am

Blue ice on the 727 forward lav access panel has led to at least two (that I know of) in-flight separations of the number 3 engine. The lav ice being ingested into the engine stopped its rotation so suddenly that the engine essentially torqued itself right of the airframe...

The first incident I can recall was a National 727 enroute from IAH (or MSY) to the west coast, back in the 1970s. The other was back in 1985, and involved an AA flight DFW-SAN. Ironically, both separations took place over the state of New Mexico. (Let the Roswell/UFO conspiracists begin).  Big grin

The National 727 report is too old for the NTSB's online database, but here's something on the more recent American flight.


Here in the US (after the AA incident) FAA put out various airworthiness directives (ADs) that directed attention at the lav dump valves on 727 and other aircraft. Not to say there has never been another lav leak since, but you sure don't seem to hear about it here like you used too..
ALL views, opinions expressed are mine ONLY and are NOT representative of those shared by Southwest Airlines Co.
Posts: 207
Joined: Thu Sep 28, 2006 7:38 am

RE: Blue ICE

Wed Apr 11, 2001 9:55 am

Should the tail skid not retract, a larger concern would be if you have enough fuel for destination. Blue ice would be the last of your worries. I think that's what airline coffee is made of..
Posts: 3961
Joined: Fri Aug 25, 2000 1:18 am

RE: Blue ICE

Wed Apr 11, 2001 3:33 pm

That blue ice falling from the sky is someone took a dump on the airliner that just passed over.
Chicks dig winglets.
Posts: 75
Joined: Sat Apr 07, 2001 3:14 pm

RE: Blue ICE

Thu Apr 12, 2001 2:03 am

The chemical is called "Raccasan".

I have seen pretty big dents in the Horizontal stabilizer LE (and this happens to the Right side! :-( )

The #2 engine have also got damaged fan blades due to blue ice from the fwd toilet servicing panel.

Most of the causes for blue ice as I know of is that the one that services the toilet, removes the rubber seat on the flush connection, and when the a/c gets airborne, there can be a backflow from this line. Creates a blue ice from 0.5 kg to 2.5 kg.

If the upper drainvalve should fail to seat due to hairbrushes, soap canisters, vibrators or other belongings to pax (belive me I have removed them  Smile/happy/getting dizzy )
There has also been installed a ball valve in the drain line inside of the servicing point on a/c with fwd toilets. That will help on this problem.


Posts: 603
Joined: Mon Aug 09, 1999 8:25 pm

RE: Blue ICE

Thu Apr 12, 2001 4:37 am

vibrators? huh? someone didn't want to decleare this at customs I guess

Posts: 460
Joined: Fri Dec 15, 2000 4:18 pm

RE: Blue ICE

Thu Apr 12, 2001 12:52 pm

Yeah, and the AAL B727 dropped it's #3 motor into a Indian reservation in New Mexico. So they found it in "Engine" country. My apologies for not being Politically Correct. (The Mescalero Apache made jewelery out of it, set it up by the side of highway US54 , and sold it piece by piece).  Big grin)
"Eagles soar. But weasels never get sucked into jet intakes.."

Who is online

Users browsing this forum: 737tanker, GalaxyFlyer, speedbird9, VirginFlyer and 1 guest

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos