Wings de-icing query.

[J B L]

Sitting in the plane here in Venice, waiting for the de-icing to finish and just wondering what is the stuff made of? It looks like a thicker car wash shampoo.

Also, the whole operation takes quite a while, it might not be cold enough here (snow more like) but in colder places what's to stop the first wing to freeze again whilst the truck is going over the rest of the plane?

Dull questions I admit but just curious and a bit bored too.

Cheers.

[Eric Mc]

I think it is a stronger version of the stuff you can spray on your car windscreen. And yes, in very cold conditions, repeated applications are required. The consequences of geting it wrong can be very bad.

[Simpo Two]

I have a memory of inflatable rubber 'boots' on the LE which cracked the ice off. Now which era/palne would that be?

[Hugo a Gogo]

somewhere cold they have to do it quick, tip the pilot the wink, and off he goes very quickly

[Munter]

Simpo Two said:

I have a memory of inflatable rubber 'boots' on the LE which cracked the ice off. Now which era/palne would that be?

One with that system crashed in the US. I'm sure it was near a place beginning with a C... It was on one of those Air Accident Investigation things.

http://www.nytimes.com/2009/02/13/nyregion/13crash...

Not the one I was thinking of (too recent). But the same system described.

Edited by Munter on Friday 17th December 14:44

[Davel]

It's a solution containing Urea nitrogen, which is also used on runways etc as it doesn't damage the engines etc. It's not abrasive like salt or sand.

Or at least it was a few years ago....

[JVaughan]

its also has quite a viscous PEG (poly ethelyne glycole) base .. and is sweet to the taste (dont ask me how I know !!)

[SeeFive]

Yes, it seems it will re-freeze under certain conditions.

Coming out of JFK after an ice storm, they set up the aircraft de-icing close to the end of the runway to avoid the long taxi and obvious re-freeze on the way there from the gate.

Taxi out, switch off, de-ice, restart and off pdq.

Seemed to work, I got home.

[JWH]

Munter said:

Simpo Two said:

I have a memory of inflatable rubber 'boots' on the LE which cracked the ice off. Now which era/palne would that be?

One with that system crashed in the US. I'm sure it was near a place beginning with a C... It was on one of those Air Accident Investigation things.

http://www.nytimes.com/2009/02/13/nyregion/13crash...

Not the one I was thinking of (too recent). But the same system described.

Edited by Munter on Friday 17th December 14:44

You're thinking of the Colgan Air crash at Buffalo - aircraft was a Bombardier Q400 (same type as the tuboprops operated by Flybe). It's still a commonly used system on a lot of light - medium turboprops and functions fine when used correctly in appropriate conditions.

[Chrisgr31]

I saw the private and co-pilot of a private jet using a couple of cans of car deicer to deice their aircraft the other week.

Saved themselves the cost of the airports deicing!

[magpie215]

it is usually a heated glycol solution for deicing aircraft.
depending on the concentration of the solution and ambient conditions dictates the holdover period between applications.

[magpie215]

Simpo Two said:

I have a memory of inflatable rubber 'boots' on the LE which cracked the ice off. Now which era/palne would that be?

pneumatic leading edge boots are still in current use. Mainly used on turboprop commuter aircraft.

[Eric Mc]

They've been around since the 1930s at least. The DC-3/C-47 had them.

[Deva Link]

magpie215 said:

it is usually a heated glycol solution for deicing aircraft.
depending on the concentration of the solution and ambient conditions dictates the holdover period between applications.

There was an airport on some news pictures the other day where they were giving the planes another blast of de-icer at the atart of the runway.

[magpie215]

Deva Link said:

magpie215 said:

it is usually a heated glycol solution for deicing aircraft.
depending on the concentration of the solution and ambient conditions dictates the holdover period between applications.

There was an airport on some news pictures the other day where they were giving the planes another blast of de-icer at the atart of the runway.

Not that unusual the aircraft can start icing up on the taxi out from the apron to the runway.

[Eric Mc]

Didn't SAS lose an MD-80 when ice flew off the wing into one of the rear mounted engines during the take off roll?

[bluesatin]

Interesting de icing at T5 last night. 30- 50 planes waited approx 4 hours after landing (of which I was one of them) to get a stand while they de-iced the plane waiting to leave. Next time i will bring a bottle of Halfords deicer and give to Willie Walsh!

[psgcarey]

flying back out of Detroit last Sunday they were using two de-icers per wing, but did it at the terminal bfore leaving

[FuzzyLogic]

Commercial aircaft must undertake two stages of external ice prevention (if required). First the a/c must be de-iced. Once de-iced, anti icing fluid is applied. The anti icing fluid will have what is known as a 'hold over time' - which changes depending upon temperature, ambient conditions, weather etc. If the aircraft is not in the air by the time the hold over time expires, the process must start again.

This wiki page is quite good: http://en.wikipedia.org/wiki/Deicing_fluid

Edited by FuzzyLogic on Saturday 18th December 13:36

[Flintstone]

FuzzyLogic said:

Commercial aircaft must undertake two stages of external ice prevention (if required). First the a/c must be de-iced. Once de-iced, anti icing fluid is applied. The anti icing fluid will have what is known as a 'hold over time' - which changes depending upon temperature, ambient conditions, weather etc. If the aircraft is not in the air by the time the hold over time expires, the process must start again.

Edited by FuzzyLogic on Saturday 18th December 13:36

"Must"? Try telling russian pilots that, I've seen them go flying with stuff on their wings that would make your hair curl. Anti-icing fluid (after de-icing) is only required if conditions are likely to result in further contamination ie, snow, freezing rain etc. If it were a clear, cold day then removal of frost/ice only would be required. No need for anti-ice fluid if ice isn't going to reform.

Types are (mainly) I, II, III and IV. Type I is de-ice fluid with little or no holdover properties. The others are predominantly anti-ice fluids to prevent recontamination and holdover times will vary dependant upon ambient temperature, the fluid mix ratio and type of precipitation which will dilute the fluid. Once the holdover time is up if you're not airborne then it's back to the bay for another dose.

Anti-ice fluids are designed to shear off the wing at a speed just before rotation (take-off). Type IV is used on jet aircraft with higher rotation speeds compared to Types II/III for (say) turboprops. There's a certain type of small bizjet that has to add a few knots to its rotation speed (Vr) to ensure the wing is clean.