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Author Topic: De-Icing.  (Read 10087 times)
strangr
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« on: December 19, 2009, 08:09:19 PM »

Ok, so i've spent a bit of time this weekend listening to the JFK and Philly feeds (thanks to those users that lets us tune in.

What i am really curious about, considering it is bad weather at the moment, Why do planes de-ice so far from take off. In about 10 minutes listning to JFK tower i heard as many 6 planes return to stand for De-Icing.

Now i come from australia so we don't have ice issues at out airport, ask anyone here what de-icing is like and no one would no.

So i wonder why not place a de-ice stand closer to the runway where planes can de-ice before the hold short command.
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kea001
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« Reply #1 on: December 19, 2009, 08:51:55 PM »

The central deicing facility requires a lot of space. It's not a matter of sticking it short of the hold-short line.
That's my guess. However if this answer doesn't satisfy you, you might get a better answer from

From the Flight Deck (Captain Doug Morris)

============================

Toronto’s Central De-Icing Facility

"The CDF at Toronto’s Airport is the largest deicing facility in the world. Fully operational since
the 1999-2000 cold season, this 65-acre "drive through airplane wash" consists of 6 huge bays
capable of handling hundreds of aircraft daily."

http://www.fromtheflightdeckbook.com/2009/03/deice-class.html

De-Icing Pad (big gray mass), CYYZ


His email address:

askdoug@enroutemag.net

============================

Article on JFK system:

Infrared Deicing: Giving glycol a run for its money   

http://www.wingsmagazine.com/content/view/1325/38/

============================

Public Notice December 2009

Pg. 6 describes proposal to plan a central deicing facility at JFK and describes the current
method of de-icing as "fragmented and inefficient".  Added to that is the fact that there is local
pressure to deal with the environmental consequences of the current setup - runoff into Jamaica Bay
of de-icing fluid through storm sewers.

http://docs.google.com/viewer?a=v&q=cache:o5pr-xXIRPUJ:www.panynj.gov/airports/pdf/Revised-Public-Notice-for-Use-Authority-dec2009.pdf+improving+de-icing+at+jfk&hl=en&gl=ca&sig=AHIEtbSzVfKAKTwoktbIC8oRCiYJ6RdGuw

==================================================

Here's a good pdf file on the whole business of de-icing:

http://onlinepubs.trb.org/onlinepubs/acrp/acrp_rpt_014_factsheets.pdf





Air Force One, with U.S. President Barack Obama aboard, arrives in the snow at Andrews Air Force Base, Md., on Saturday. (Alex Brandon/Associated Press)

« Last Edit: December 19, 2009, 09:29:57 PM by kea001 » Logged
joeyb747
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« Reply #2 on: December 19, 2009, 11:46:02 PM »

It depends on several factors; Air temp, type and rate of precipitation, and expected wait time in line to take off. Most airports do have areas near the ends of runways where deicing can take place. Most aircraft will deice at the gate, and get sprayed again if needed before takeoff.

It also depends on the type of fluid used for deicing. Different types have different holdover time limits. If the airplane exceeds this time limit due to heavy traffic and longer then expected wait times, then additional deicing will be required. The aircraft in question may have only had Type I fluid applied, witch only has a holdover time of 5-15 minutes. The following is from the article I linked to at the bottom:

"A single application of Type I deicing fluid to the critical surfaces of an aircraft, such as the wings, flaps, and fuselage, is the most common treatment method. Type I fluid is about 90% glycol and 8% water, but it is diluted as needed depending on ambient temperatures. It is sprayed on hot (150 to 180 F) at high pressure to melt or remove ice, snow, or sometimes just frost. Deicing may take place at the departure gate or at a central facility near the runway mainly by using handheld nozzles, although automated machines called gantries have been developed.

Deicer performance is measured by holdover time, which is the length of time an aircraft can wait after being treated prior to takeoff. For Type I fluids, the holdover time is only about five to 15 minutes, so the aircraft has to take off right away or else wait to be deiced again.

When a longer holdover time is needed, a two-step process is used in which deicing is followed by treatment with an anti-icing fluid. Anti-icing fluids can be either Type II or Type IV, although Type II is slowly being discontinued in favor of Type IV. Type III anti-icing fluid, designed for small commuter aircraft, is no longer used. The anti-icers, which are sprayed on unheated, are 65% glycol and usually are not diluted further. They contain a sufficient amount of a polymer thickener to enable a heavier layer to be applied. For Type II and Type IV fluids, the holdover times are about 30 minutes and 80 minutes, respectively."


http://pubs.acs.org/cen/whatstuff/stuff/7901scit5.html

Below I have attached some photos: The first one is deicing at runway threshold. The second is deicing on a taxiway on the way to the runway. And the third is deicing at the gate area. Hope this helps!
« Last Edit: December 20, 2009, 12:13:25 AM by joeyb747 » Logged

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joeyb747
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« Reply #3 on: December 19, 2009, 11:57:06 PM »

Additionally, here is the airport diagram of KDTW. If you look at the end of Runway 21R to the left as you look at the diagram, you'll see a large deice pad. At the end of 22R, 21L/27R, 3R, 27L, and 4R are areas of wider taxiway that is commonly used for deicing. For 22L, extra deicing usually takes place on the apron near the end of the runway. For 3L, the area between taxiway PP and PP2 is commonly used. Like I said, I hope this helps!  cool

« Last Edit: December 19, 2009, 11:58:41 PM by joeyb747 » Logged

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kea001
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« Reply #4 on: December 20, 2009, 03:23:14 PM »

So what you're saying is it is quite common from your experience to have deicing near the threshold, that the deicing procedures and equipment are more portable than I've demonstrated is that right Joey?

I think part of the problem with JFK yesterday that may have led to so many planes returning to apron was the a) usual congestion and b) the runways were closed for about an hour or so.

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joeyb747
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« Reply #5 on: December 20, 2009, 07:35:55 PM »

I agree with you on the reasons for needing extra deicing. As I pointed out in my previous post, Type I Fluid only has a holdover time limit of 5-15 minutes, after that time frame, they need to be deiced again.

Most deicer services in use today are via a boom truck. Some are owned and operated by a service provider, others are owned and operated by the airline themselves. Attached below are some pics.

First pic is a generic deicer truck. Second is a deicer truck owned by Aeroflot. Third, is a pic of a deicer service provider at Dusseldorf. If you look close at the lase pic, on the side of the truck it says "SAE typ IV", meaning this particular truck has type IV Anti-ice fluid on board.

Here is a vid of Deicing at KDTW. This takes place near the runway threshold. Airplanes line up side by side and get sprayed. These trucks are owned and operated by NWA itself.



Here is an Avro RJ85 being deiced at the gate area in Helsinki. The truck in this vid is owned and operated by Finnair.



Central deicing at Toronto shot from the cab of the deicer.



Enjoy!  smiley
« Last Edit: December 20, 2009, 07:40:47 PM by joeyb747 » Logged

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Robin Rebhan
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« Reply #6 on: December 20, 2009, 09:38:21 PM »

     Deicing fluid containment is a factor in preventing this form of pollution from entering water table and waterways. Laws of course depend on state and country. And this in turn has influence where suitable location(s) for deicng operations can take place on the airport.
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joeyb747
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« Reply #7 on: December 20, 2009, 09:44:24 PM »

Very true. Also from the article I linked to above:

"Apart from safety, environmental protection is an important aspect of deicing. Besides the mammalian toxicity of ethylene glycol, there is concern about aquatic toxicity of the glycols because they can deplete dissolved oxygen in streams or lakes as they biodegrade. There also is concern over the toxicity of urea and the additives, particularly tolyltriazoles used as corrosion inhibitors and flame retardants. The Environmental Protection Agency requires airports to monitor storm water runoff, which is usually controlled by local discharge permits. Depending on permits and economics, airports may contain and treat storm water on-site, send it to a municipal wastewater treatment facility, have it hauled away by a contractor to be treated or recycled, or discharge it untreated."

http://pubs.acs.org/cen/whatstuff/stuff/7901scit5.html
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SkyViking
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« Reply #8 on: December 26, 2009, 10:58:19 AM »

One of the key elements of the YYZ facility is that 100% of the runoff is contained and no fluids reach any storm sewers.
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kc135dood
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« Reply #9 on: January 19, 2010, 12:03:58 AM »

Deicing and Anti-Icing regulations from different deicing company, to airline, and to country.  Here's what I know:

Types I and IV are most abundant in the United States.  Hold over time for type IV can last from 10-30 minutes(definitely not 80)!  Much deicing takes place on a dedicated "deicing pad" that has many drains within it.  It's not uncommon to see a dedicated tower for those deice pads as well.

Tower-relays instructions to the inbound aircraft to taxi to which place/slot/area.
Tower-then passes on the "Ship number" or even possibly the aircraft's registration.
Iceman operating the deicing equipment can either talk to the pilot directly via airband radios or the tower does it for them.
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joeyb747
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« Reply #10 on: January 20, 2010, 08:33:14 PM »


 Hold over time for type IV can last from 10-30 minutes(definitely not 80)!  

Hold over time on type IV can be as high as 80 mins. It depends on the type of precip, fluid concentration, and air temp.

Checkout the table below, in the "Freezing Fog" catagory, hold over time is as high as two hrs, fifteen mins (75 mins).

For "Frost", it's as high as 18 hrs!  wink  cheesy

"THE TIME OF PROTECTION WILL BE SHORTENED IN HEAVY WEATHER CONDITIONS.  HEAVY PRECIPITATION RATES OR HIGH MOISTURE CONTENT, HIGH WIND VELOCITY, OR JET BLAST MAY REDUCE HOLDOVER TIME BELOW THE LOWEST TIME STATED IN THE RANGE.  HOLDOVER TIME MAY BE REDUCED WHEN AIRCRAFT SKIN TEMPERATURE IS LOWER THAN OAT."

From (and chart):

http://www.aircraftdeicinginc.com/ai%20holdover_tables.htm

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kc135dood
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« Reply #11 on: January 20, 2010, 10:03:59 PM »


NO KIDDING.. wow!!!!!  I was just going by what I learned as a deicer.  But gosh.. I think I like the rules of Northwest and Delta with a maximum of 30 minutes.  At least it seems that way, many come back if delays occur in DTW.

And your an A&P!  That's what I'm soon to get my exams done with, I am complete with all my hours of A&P training.  Oh, make note, I maybe able to get DTW's feed going ASAP!
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joeyb747
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« Reply #12 on: January 20, 2010, 10:41:35 PM »

Welcome to the family kc135dood! Glad to have you here!  grin

A DTW feed would be awesome! I've wanted one for a while, like I said, I would host, but I live too far away.

KYIP would be cool too...lots of cargo and the Yankee Airforce is out there. They have a flyable B-17G, a B-25, and a C-47. Also they do the airshow out there. Most of the time Willow Run would be quiet thou...
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kc135dood
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« Reply #13 on: January 21, 2010, 12:10:12 AM »

Actually Willow Run would be quite something to listen to.  I've been there 5 days a week for the past two years and there is an abundance of air traffic.  Comparable to DTW, not, but still would be sweet to provide a feed for them.  Though unlikely there.
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