Aircraft De.icing

[GRIZZLER]

Can anybody give me a rough idea on how many ltrs of de.ice fluid it would take to do wings and body on a AB330 in falling snow at -1 degrees........as i asked how much was put on an aircraft last night.....i was told just over 320 ltrs.

I cant think that with such a small amount the job was done correctly....as only mins before i had been in a de.ice rig putting between 700 and 800 ltrs on AB 320S wings and tail......in the same conditions.

There must be an amount that sounds correct for type of aircraft sprayed...give or take a few ltrs....but to me...320 did not seem enough....Glad i was not flying on it.

The engineer who signed it off said "Fluid is expensive stuff".....i said so is losing a plane!!!!

[UKSquiff]

That's quite scary really...It's the sort of comment made by people on Air Crash Investigation on NatGeo

[firefish]

If he states that you're good you can bet that you are, even if the commander has the final responsibility his head will roll too in the case of any incident related to insufficient de-icing. No two situations/conditions are the same and any comparison between two de-icing cases is moot.

What you should have been doing, if you felt insecure about if the de-icing was properly conducted, was getting out of your seat and checking it for yourself. Part of our job is taking other professionals words for granted, it is something we have to do as we have neither the skill nor the time to check every aspect or detail of a flight. However, it is our responsibility to check everything that we suspect may be wrong, either by ourselves or by seeking a second opinion from a professional.

If you felt the need to ask here if the amount of fluid was enough (post flight!!!) I can only assume that you didn't check, otherwise you would have known, and took off anyway. Now that's something that one really could have opinions about....

Edit: saw that you weren't part of the crew - sorry.

[hedgehopper]

Recommend minimum amount of fluid for anti-icing

wing tail total

A320 180 50 230
A321 180 50 230
A330 -200 480 100 580
-300 480 100 580

Source:
AEA Training Recommendations and Background Information for De-Icing/Anti-Icing of Aircraft on the Ground - 7th Edition August 2010

The amount to De-ice will vary upon conditions.

Regards HH

[GRIZZLER]

Myself and my de.ice buddy in the basket...if we are asked to de.ice...that is what we do....a tactile test ..then we spray until we cant see any more ice or snow on the parts of the plane that we were asked to do.....followed by another tactile test at the end.

after all, our name is on the paper work......if i am told by the engineer or any body else to be sparing and not use to much fluid i would not do it at all....i do not tell them how to do there job.......and yes i know it cost a lot of money.....but i dont get any of it.

ps dont do any anti icing so dont know much on that side of things.

[Dr Illitout]

Perhaps the engineer was saying it "Tounge in cheek"?
More often than not my fellow engineers and I have to battle with ground staff who don't want to do it!
We have to re qualify every year to supervise de icing. It some time seems to me that some of the ground staff hear have only the very basic training, if any.
Don't worry. When I'm supervising it, it get done right!

Rgds Dr I

[GRIZZLER]

Well Dr Illitout ...you are not the only one that has to get passed out every year for de.icing........so do we......we also have to know the hold over times for the weather conditions that we are spraying in ie...frost.freezing fog, rain,snow...and so on and air temp.....so when was the last time you see the top of a 747 tail fin in the dark at -5 degrees or on top of a 146 tail plane....you cant with out a de.icer basket....we can so we know what the conditions are like up there.

I dont think that the AB 330 should have been de.iced and let go using only 320 ltrs.... the hold over time in those conditions on the paperwork i have to use only gives 15.min....(thats a type 2 fluid)and thats from the time you start the job....it took him longer than that to de.ice the total the aircraft.....even using that small amount.....and it still had to call up.push back and get to the runway.

last year in similar snowy conditions i was asked to de.ice a cargo 747 ...i told the captain what the hold over time was ......and that i would not be able to get round the plane and finish the job in 15 mins...it was up to him....it did not fly that day.....and i had a good nights sleep.

and as for supervise...how the hell can you do that from the ground...you cant see jack s**t.....unless you are a geeeraffe????.

and as a foot note i love de.icing......it makes a pleasant change from all the other jobs we do....been doing it for at least 14 years...maybe longer

and no the engineer was not talking tounge in cheek.

[tigger2k8]

Had any snow built up on the aircraft? (Significant amount?) While i cant comment on the A330 as i have never de-iced one.. on smaller jets such as the 737/A319/A320/A321 in frost between 150-230ltrs, in falling snow in which much hasnt built up between 300-400ltrs, in heavy snow in which theres about an inch of snow on the wings/fuselage (when the crew dont want to wait for it to be brushed) 550-750ltrs.. the above figures are what i personally use, i know some who use more or less..i did use 1800ltrs once on an A300 which was covered in snow

At the end of the day, everyone uses different amounts of fluid, some people use different spray settings.. ive seen 1200ltrs go on a 737-700 before in heavy snow. The way i see it is, if im signing for it, ill use as much as im happy with to be satisfied that the aircraft is ice/frost/snow free and safe for flight and if anyone pulls the old "cost" line which hasnt happened to me yet, ill set them straight

[GRIZZLER]

tigger2k8 as i said before....on that same night in falling snow we were putting 700 to 800 ltrs on AB320s and they had only been on the ground for about 45 mins..........the AB330 had been sitting there for a couple of hours at least...

i am with you...if my names on the chit....it gets what it needs to get rid of the ice....or i will not do it......no engineer can tell what its like on top of the aircraft.

in fact in the early hours of the next morning we put over 700 ltrs on a small prop job saab that was doing a mail flight.....with the amount of ice that had built up on its wings and tail i cant see how you could have done it with less....unless you hit it with a big stick.

one other thing.....has any body heard about washing snow off with hot water ...then do the de.ice....sounds like a bad idea to me...never seen it done myself...but sombody did ask if we could do it???

[Piper19]

Some amounts of type II I remember from this week: 480, 604, 9??, 1045 and 1200
So it all depends I guess
Average was 45 min on grnd, very light snow falling

[tigger2k8]

Sorry Grizzler, had read it too quickly missed out on a few bits. Had you seen the finished job, was the person who was de-icing happy with it, did they say anything, are they long out of training? To be honest if i was doing it, there would have been 320ltr on each wing, not including the tail and fuselage but then i have always been very cautious. If you are concerned i would refer it to whoever is in charge of de-icing operations at your workplace

Yes i have heard of hot water de-icing, never saw it happened but as far as i know its used in some areas.. sounds risky, but to be honest you can blast the snow off for minimal cost (as airlines want this) then give it a quick spray with de-icing fluid, could probably save a a couple of hundred ltrs by doing it.. but it could leave you with one slippy apron...

[TOWTEAMBASE]

HEDGEHOPPER

7TH EDITION ?????? should that no be 27th ??? sounds like you got an out of date copy ;-0. well said GRIZZLER...i know what you say is true, ive seen it myself. maybe a comment or 2 to CHIRP could set your mind at rest

[hedgehopper]

TOWTEAMBASE

If you are a De-icing/Anti-icing certified operator, then I guess you got one or two questions wrong on your annual training?


FYI

http://files.aea.be/Downloads/AEA_TrainingMan_Ed7.pdf

and

http://files.aea.be/Downloads/AEA_Deicing_v25_revb.pdf

Not a 27 in sight!

Regards

HH

[boredcounter]

I do not fly, and I do not de-ice aircraft, I am however Ops.

I do have a serious question though.

Take type II (Generic) 50/50 mix, de-ice with no anti-ice.

A/C takes 500 Lts to be de-iced to everyones satisfaction.


Hold over time is not applicable.



What is the de-ice bill?
Is it billed as 250Lts of XXX TypeII or total used @ mix rate?




Cheers for answers,

bored

[groundagent]

What is the de-ice bill?
Is it billed as 250Lts of XXX TypeII or total used @ mix rate?


It would be billed as written in the SGHA. Normally reference to either a rig call out fee and a couple of rates for 100% de-icing fluid, 75/25 mix. Alternatively, no rig call out and a specified retainer and a higher rate for the fluid at different mixes.

Not certain, but I don't think 50/50 is used, but I am not a de-icer either so happy to be corrected . . .

GA

[spannersatcx]

depends on what type of fluid you are using Type 1, 2, 4, mix ratio 50/50, 75/25 or 100% and the manufacturer and ia it hot oe cold.

We have been using 75/25 hot type 2 Kilfrost ABC-K plus and the hold over times in snow at -1C is something like 1hr 25 mins. Many years ago with older type fluids you were wasting your time in snow but nowadays they have improved immensely.

Much would depend on if the wings were cold soaked or not, frosty before it snowed or not, or if it was just a light coating of snow, so to say 320 lts is not enough is completely unfounded.

I was responsible for the removing/deicing of a 744 last week in the snow and we used anything from 500-800 ltrs, no 2 a/c are the same. So could you do an A330 with 320 lts of course you could. Could you use 800 lts on an A320 you could but I would suggest unless there was 4 foot of snow on an extremely cold soaked wing I would say that was excessive and would be questioning the operator, after all I am the one signing the a/c out as fit to fly not the rig operator.

[Out Of Trim]

This year I have seen occasionaly some "Salmon Pink" coloured fluid used. Is this stuff anti-ice rather than de-icer?

:cool:

[FEHERTO]

Hi, where you got this fluid.

Salmon pink is not a standard colour in accordance with the specifications for aircraft de-icing/anti-icing fluids:
Type I: red or red-orange
Type II: not coloured, but sometimes pale (exemption one fluid, which is yellow, as produced before specification came into force)
Type III: yellow
Type IV: green

[TOWTEAMBASE]

hedgehopper

yes i am, and you woud be wrong, i pass with flying colours every year. you see, its important for me to know whats written IN the AEA, not whats written ON the cover. ours is a controlled copy, so up to date all of the time. we all make mistakes hey ;-0

[GRIZZLER]

I am sorry mr spannersatcx....but i dont dont think you could get round a 747 in 15 min in falling snow, the hold over time would have expired before you had finished....unless your rig is a converted ferrari with jenson button at the wheel.....we use ecowings26 type 2....but i dont think the hold over time for kilfrost is 1 hour 25 mins in snow...we can only give 25 mins in freezing fog....as we did last night....i think you should look again at your de ice paperwork....again

and the recomended minimum for de.icing 330 air bus wings and tail 580ltrs...according to the AEA handbook...and thats still more than was sprayed on the total aircraft .....so i still say it was not done correctly.

if you take time to look in the AEA de ice handbook it gives it gives the recomended minimum fluid on most aircraft known to man.

as for the killfrost times you gave on the abc-k plus at -3 degrees 75/25 mix its only 35 mins holdover..minimum.....even at 100 percent its still only 1 hour hold over minimum........not sure how you get 1.hour 25 mins out of that......at least thats what the FAA say.

[TURIN]

GRIZZLER.

Sounds like you've been out in the cold too long this winter. Calm down, no-one is trying to score points here, just offering advice and info based on their own experiences.

Dr 'I' knows his stuff as I'm sure you do too. He may not be 30ft up there doing a clear ice check at 5 in the morning but if he signs the tech log or the transit check on the a/c then it is he that is taking the responsibilty for the de-icing. So, when he says 'supervising' what he really means is that he hopes to hell people like you know what you're doing as he has to go on trust that you do.

Likewise, SpannersatCX has been doing the job long enough to know what he is talking about.

For what it's worth.

Kilfrost ABC II K-Plus.

At -3C and above in snow.

100% Holdover 1:00hr to 1:40hr.
75% Holdover 35 min to 1:10hr.

[spannersatcx]

the 1:25 was off the top of my head as I was at home, just trying to give an opinion based on experience.

Grizzler I think you need get out of East Anglia from time to time:)

Not really interested in what the FAA says as I am not governed by their rules and regs.

As Turin quite rightly says it's 35mins to 1:10hr depending on conditions, I was getting it mixed up with freezing fog at -10 which is what I encountered the other day. Even ecowings will give you upto 45mins at -3 in snow. But it's all subjective anyway as it depends on the conditions at the time and they vary somewhat.

It's quite easy to get around a 747 in 15 mins with modern equipment and 1 rig either side.

[Ice-bore]

Looking at Mr. G’s original question and the various answers comments provided to date, I’d like to offer some clarification on a number of the points made.

Firstly, under the conditions referred to, i.e. falling snow at -1 deg C, the aircraft would invariably need to be de-iced, to remove the frozen deposits, then anti-iced, in order to protect the aircraft surfaces until take-off. The majority of the H/A’s in the UK tend to adopt a one-step DE-ICING/ANTI-ICING procedure, using a 75/25 mix of Type II fluid for this operation.

From a purely de-icing perspective it’s not possible to suggest how much fluid is likely to be required for removing the contamination as there are just too many variables. For example, type and amount of snow, OAT, temperature of the structure, fluid type/concentration/temperature, gun/nozzle flow/pressure and the expertise of the de-icing operative, to name but a few... The amount of fluid to be used for this part of the operation will/should therefore be the minimum fluid required (by that de-icing operative) to remove all frozen deposits, under the prevailing conditions.

Now, as hh points out in post #4,the AEA does publish recommended minimum amounts of fluid to be used for protecting the surfaces (anti-icing) of the various aircraft types. Based on this information it would be difficult to understand how an aircraft could be de-iced and anti-iced (in a one-step operation) using significantly less fluid than that recommended by the AEA for just anti-icing.

Mr. G, in post #5 you state that you perform a tactile check before and after de-icing, presumably this is only on those aircraft where the manufacture mandates such a check, i.e. those aircraft types that have experienced significant problems with clear ice, e.g. the MD-80?

Regarding your question on hot water de-icing (post #9), it is permitted down to -3 deg. C but only as the first step in a two-step operation. You can find information on it in Table 2 (page 28) in Edition 25 of the AEA Recommendations at AEA - Publications (http://www.aea.be/press/publications/index.html#de-icing)

The main problem is that the second step must be carried out within 3 minutes of the first step, so you would need to clear an area of say the wing then protect that area, i.e. anti-ice it, within 3 minutes. This then needs to be repeated over all appropriate surfaces. The other issue is that although an approved procedure, most people associated with aircraft tend to feel uncomfortable with spraying hot water on an aircraft, when the structure or OAT is at or below 0 deg. C.

TTB (post #21), not sure you have a controlled copy but by clicking on the above link you will always be taken to the latest edition...

Mr. T (post #23), it may be worth clarifying that the lower limit of the published time span is used to indicate the estimated time of protection during moderate precipitation and the upper limit indicates the estimated time of protection during light precipitation.

Mr. s (post #24), actually the FAA and TC fund the ongoing work to produce both the generic and brand name holdover time tables and publish the updated information prior to each winter. We in Europe then use this information to base our procedures on.

[GRIZZLER]

At the moment thanks i seem to be in the best part of East Anglia...the least snow and only -4....i will wait for the weather to pick up before i go further afield....

I dont want to go on and on about my first post about de.icing....but going back to basics....its not the de.ice fluid that melts the ice....it is the HEAT of the fluid that melts the ice.....the amount and fine quantity of the spray that was used could not have made a AB330 warm enough to go through ice and standing snow....with just 320 odd ltrs.....no matter what sort of de ice fluid was being used.....that only comes into its own when the ice has gone....


just becuase you have sprayed the whole plane it does not mean the ice has gone.......it could still be ice covered in fluid.

and thanks Ice-bore you seem to have covered most things there....

From reading these posts it seems that we all get our information from the same source but do the job in a different way....very strange.

and off the top of my head.....as i am also at home......ecowings type 2 will not give you 45 mins hold over in snow ....not with the chart we use.....i am pretty certain it is 15mins up to 35 mins....but we have to put the lower time down on paper......thats with a 75-25 mix.

I'm getting a bit ice bored myself now.......t.t.f.n

[TURIN]

I dont want to go on and on about my first post about de.icing....but going back to basics....its not the de.ice fluid that melts the ice....it is the HEAT of the fluid that melts the ice.....the amount and fine quantity of the spray that was used could not have made a AB330 warm enough to go through ice and standing snow....with just 320 odd ltrs.....no matter what sort of de ice fluid was being used.....that only comes into its own when the ice has gone....

Point of order M'lud.

I may be misreading the above quote but the de-ice process is not designed to heat the airframe.
As I'm sure you are aware, the type of de-ice fluid used will give holdover times based on it's ability to withstand re-freezing. Not heat transfer.

I'm glad you understand the process as there are too many that still think the ice is removed by hydraulic action or chemical reaction. :ok:

[GRIZZLER]

I thought i put it clear enough...its the heat from the fluid that melts the ice....the de.ice fluid stops it reforming on body parts,wings ect so aircraft has correct airflow over and under wings during take off.....fluid shears off when aircraft takes off............ (basic version) for none de.ice person.

i have watched people de.ice doing a spot here and a spot there on the wings...so not all of the wing has been done...they only spray the ice they see.....so ice must form on the bits they did not spray .....so there is no point in doing five spots on one wing and three on the other.....its got to be symmetrical.

[tigger2k8]

and off the top of my head.....as i am also at home......ecowings type 2 will not give you 45 mins hold over in snow ....not with the chart we use.....i am pretty certain it is 15mins up to 35 mins....but we have to put the lower time down on paper......thats with a 75-25 mix.according to the AEA which is the chart we used for some time.. 75/25 | Type II | Ecowing 26

-3 and above = 15-30 minutes
-3 to -14 = 10-20 minutes

although there are many different hold over charts out there, as we have found that the various airlines we have de-iced over the years some kick up a fuss when the chart we use is different to theirs, as far as i can remember the EZY hold over chart, cant remember what one they use i think its Transport Canada.. will give 1:05-1:55 in freezing fog (-3 and above) where as the AEA will give you 0:25-1:00 in the same conditions... theres a significant difference

[Ice-bore]

.
The FAA and Transport Canada sponsor the holdover time testing of Type II and IV de-/anti-icing fluids and publish holdover time tables for each individual fluid, on an annual basis. These are known as brand name tables.

They also publish generic Type II and IV holdover time tables, where they publish the lowest (worst case) cells from each of the individual Type II or IV holdover time tables. This makes life simple in that only one table is required for each fluid Type. The AEA only publishes the generic tables and leaves it to the user to obtain brand name tables from the FAA or TC websites if required.

http://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/media/FAA_2010-11_Holdover_Tables.doc

Operators have to make a decision as whether to provide their flight crews with just the generic tables, the generic tables plus the brand name tables for the fluids used at their main bases, or less likely all the brand name tables.

The figures you quote are indeed from the generic Type II holdover time table as published by the FAA and TC and subsequently adopted by the AEA. However, if you look at the Ecowing 26 times under the same conditions (snow) you get:

-3 and above = 25-45 minutes
below -3 to -14 = 25-40 minutes

Operators who only publish the generic tables to their flightcrews would not therefore benefit from the additional time provided by this fluid.

The times you quote under fog conditions, i.e. 1:05-1:55 (hours:minutes) at -3 deg C and above, is from the Ecowing 26 brand name table (75/25), whereas the 0:25-1:00 cell is as you say from the generic Type II table adopted by the AEA.

[safewing]

Icebore is right

While the generic charts offer the "safest" option by placing the greatest restriction on holdover times, one would have to question why airlines, knowing what they know about winter weather delays would ever want to use them.

While I'm not rubbishing them (as not all brands of fluids have their own brand specific holdover times) if the fluid application time or airfield delays are greater than the holdover in the generic charts it just becomes an exercise in wasting money and time.

Moreover I believe it can and does put aviation personnel in difficult positions.

If your airline does not recognise the value of brand specific holdover perhaps now is the time to enlighten them.

[Flightmech]

GRIZZLER.

Did they 2-step it? DE-ICE the aircraft to obtain a clean wing then ANTI-ICE to prevent reform and give sufficient holdover time to get airborne? In falling snow, it is normal to 2-step the aircraft as DE-ICE only doesn't provide much holdover.

Maybe they only need 320 ltrs of DE-ICE fluid to clean the surfaces (not that contaminated), then ANTI-ICED afterwards. Just a thought

[GRIZZLER]

My self on the headset and the tugdriver were waiting for aircraft to be de iced.....No there was no step 2 de,ice....just turn up in the snow and spray a mizerley amount....it had been snowing for over an hour and a half and the aircraft was on the ground during that time...... what they put on the total aircraft was nowhere near the minimum requirements for just wings and tail laid out by A.E.A......which off the top of my head is around 580ltrs...but dont hold me to that.

as for step 2 de ice......as some posts say spray with hot water first,then de ice.....the airport authority dont even like the waters to be drained from tanks when aircraft stop over night as it freezes leaving sheet ice...so cant see them wanting loads of water on the ground from de icing.

[Flightmech]

OK fair point, but remember minimal requirements are guidelines only. As long as enough fluid is sprayed to remove ALL contamination from surfaces then that should be sufficient.

At my employer, maintenance also perform de-icing. You'll be amazed how little fluid you can get away with, especially if only spraying to remove frost on the upper surface of an outboard fuel tank etc.

Like people have said, every situation will be different depending on aircraft type, contamination type & level and weather.

[FEHERTO]

The reason, why a lot of airlines, taking the subject very serious, do not use brand name tables are various:
1. Very often, onyl a few data points are used to create the tables (normally done by APS Aviatin for TCA and FAA), being not really fully representative.
2. Too often the fluid has lost a lot of viscosity, and especially the UK are a place, where you find a lot of degraded fluid. Caused by the heating of the excessive heating of 75:25 mix often used (mainly as one-step).
3. The hold-over-time tests are done by pooring fluid on a tets plate and counting the fluid failure during differnet conditions related to temperature and active precipitation. The fluid placed on the plates is normally between 3 to 4 mm, getting thiner with time. If you spray too less fluid (film thickness less than 1 mm), you simply cannot get the hold-over-time as published in tables.

Using the brand name tables require that you really know the fluid conditon as well as taht enough fluid is used for anti-icing.

[safewing]

Feherto

Perhaps if EASA's Safety Information Bulletins are translated into legislation the use of Type II as a 1 step de-anti-icer will be a thing of the past. There will be a lot of resistance to it.

My comments in the previous post pertain to the operational realities that exist in Western European airports. They don't have enough equipment and the location of the de-icing bays relative to the operating runway poses real problems of operating under the generic guidelines. I'd have no problem accepting a generic holdover time if I was confident that the operational systems in place to account for them was realised. But that is a different topic.

Would there be many examples to draw from that show insufficient data points during testing means that brand specific times are inaccurate? Has there been enough grandfather rights on the brand specific holdover times at this stage to confirm their validity?

While this topic started on the basis that someone perceives an aircraft received insufficient fluid, I think of equal concern is the opposite, getting lots because of a multitude of factors e.g. no bulk clearing of snow before spraying (not that I'd wish that job on any man) so that aircraft are receiving excessive quantities, temperature loss of the fluid and as you've said the reduction of viscosity.

Moreover the fact that the one step de-anti-ice with type II 75/25 is the only options in these countries is a concern especially with the temperatures experienced in the last number of weeks. I wonder how many airports and providers continued to spray with the OAT below minus 14 degrees Celsius? And of those that did how many did so by establishing an accurate LOUT for the conditions?

Did you enjoy Berlin in May?

[FEHERTO]

Legislation will take at leats two more years. If it gets into mandatory status, at leats 75% of the UK airports will be in troubles.

The bigger airports, with aircraft category E to G have enough equipment, the locations, I agree, are sometimes problematic.

For brand names, no grandfather rights, but sometimes the amount of data points is less than 5 for a certain cell. This needs improvement by moving the tests from free nature to lab.

To manually remove snow: As only heads are counted by accountants and controllers, it is practically impossible to organise, unfortunately.

Berlin is a nice city, but the meeting had been not really bringing something forward.

[Boardwalker]

Hi,

yesterday I flew with an A330-200/300 Aircraft, sitting next to the wings. As I saw during taxiing to the runway, the whole wing was covered with ice and snow (it was snowing quite strong). So I expected that the crew will go for de-icing before we fly. But the aircraft took off without having done any treatment. As we flew I saw that the major part of the wing was getting slowly clean, but still a huge amount of frozen ice was spread over the wing.

So my question: Is it not necessary to deice the plane before flying when you expect that the wing gets cleaner in flight? :confused:

Thanks for the reply