De-icing

[vctenderness]

Just heard a bloke on the radio saying a 747 pilot told him that it costs £150,000 to de ice one aircraft!!!!

I know this is b******s but how much is the average cost in UK for large aircraft?

Also why did they not build a static rig at T5 which could have helped this chaos considerably?

[Yellow Sun]

Also why did they not build a static rig at T5 which could have helped this chaos considerably?

At Charles De Gaulle they used to have two static rigs, one of them blew down and they dismantled the other. They were a real pain to use. For a start you had lines of aircraft queuing up with engines running waiting to get onto a rig and they were also positioned some way away from the takeoff point, so you ran the risk of running out of holdover time* before you could depart. Static rigs put all your eggs in one basket, rig goes down all is lost, a deicing truck goes down then you may have lost one of 20.

The real debate is between on stand and remote deicing. On stand is flexible and cheaper but you do have the potential hold over issue. Remote deicing accomplished by a team of vehicles at a location close to the takeoff point is operationally more desirable. It is also flexible in that you can allocate resource depending on aircraft size, e.g. 4 rigs for a widebody, 2 for a narrow body, to keep the flow going. It is however expensive in terms of manpower and equipment. It is the better option if you have lengthy and forecastable periods when deicing is necessary but (Northern Scandanavia) but in more temperate climates the decision is much less clear cut.

Sorry, but no easy answers.

YS

*Holdover time Deicing treatment is only effective for a finite time after application. This can range from a few minutes in very low temperatures with heavy precipitation to hours when the temperature is just below 0degC with no precipitation. The type of deicing fluid used is also a factor. Crews have table that combines these factors and enables them to calculate the "Holdover Time" for which the deicing treatment will remain effective and keep (primarily) the wings free of snow/ice. If takeoff is not accomplished before the holdover expires then it back for further deicing. Here is a little more from Wikipedia (http://en.wikipedia.org/wiki/Deicing_fluid) about it.

Hope that this helps.

[Donkey497]

Pearson Airport in Toronto seems to have a good set-up for de-icing. they have a de-icing pan adjacent to the runway, on a sort of by-pass from the main taxiway. The pan can take every size from a little piper prop job all the way up to an A380 (I guess) and can take three or four at a time.

Each aricraft is de-iced by two or more trucks controlled by the operators in a cabin on the spray boom. I understand that the pan has a separate drainage system which captures the run off of de-icing fluids. I don;t know if you can rececyle this or not or whether this is purely for environmental reasons.

It seems to keep the flow of aircraft moving without too much of a hold up, so I guess it must be both fairly flexible and pretty effective.

[Litebulbs]

Di-icing fluid is liquid gold and costs more than fuel I believe and wings stab and fin on a twin A or B takes between 250 - 500, depending on the level of contamination and that is just for ice. Clearing the airframe of snow drives the usage up and I hear a middle eastern B big twin took over 30K L recently.

However, this is off of a mobile rig at a base that is not really geared up for adverse conditions.

[Mike Oxbig]

@ Donkey,

Oslo Airport in Norway runs a similar system - aircraft go to the de-icing area just off the threshold of the runway to maximise the holdover time. All the fluid then drains into a holding tank, where it is filtered and then reused. when you consider the airport charge you for this fluid, and then re-use it for someone else, they must be making a mint.

Mind you, it is far cheaper for an operator than the consequences of a crash - the manchester air disaster in the 60's (date?) was caused by icing. At that time, the consequences of aircraft icing was not really understood.

[Married a Canadian]

I believe YYZ's de ice bay is amongst the largest in the world if not the largest.

and can take three or four at a time.....more like 13 or 14

[BUGS/BEARINGS/BOXES]

Typical cost for type I fluid in the uk is on average 75p per litre. Multiply by 500 litres for my aircraft the other day and thats £375. now multiply by 58 aircraft and thats £21750> Now say every aircraft flies 6 sectors a day (gotta keep those fares down somehow) and thats a daily bill of £130500. Of course not every airframe requires de-icing every turnround but gives you an idea. TypeII and IV fluids cost more. What really gets me is that wings and the fuselage can be cleared by manual means, as long as care is taken around antenna and probes etc. however, some 'elf and safety and de-ice suppliers proceedures, do not allow for this. Thus a snow covered aircraft could be in the order of 2000 Ltrs for a small short haul type, just to clear the snow off! Thats £1500 just to clear it! Then if it needs anti-icing...... you get the idea. :}

[Nicholas49]

On the topic of de-icing, could a professional pilot answer the following question?

De-icing is a flight safety issue. So I wondered whether the pilots take it as "job done" when the de-icing ground staff tell them "we've finished", or are you required to check for yourself?

I am probably answering my own question, but I imagine the de-icing has to be done after the pre-flight walk-around when everyone's on board (and doors shut for obvious reasons!) given that there is a Holdover Time, as explained above by Yellow Sun?

[BUGS/BEARINGS/BOXES]

A qulified person, usually on the de-icing team, will conduct a check post spraying to ensure the aircraft is clear of contamination. Different aircraft manufacturers and operators have slightly different drills and checks to complete post de/anti-icing. This can include delaying take-off flap selection till the holdng point for the departure runway and a full and free control check. Should snow or other freezing contamination be falling after the treatment process, the commander needs to asses whether the hold over time is still applicable and then check by visual means, if the wings are clear of contamination. If there is doubt or the checks can not verify that the aircraft is definatly fit to depart......the process starts all over again. Different temps, weather and fluid types and concentrations give different HOLD OVER TIMES that change as the conditions change. they are only a guide and not definate. If the Aircraft has been parked over night and only requires de-icing, this can be done no longer than 60 mins before departure( 45 mins in my company) and as such the aircraft may have been sprayed befor the crew arrive. It is the commanders job to ensure the treatment has worked, and order any other treatment as required.

[Nicholas49]

Thanks for that B/B/B.

Should snow or other freezing contamination be falling after the treatment process, the commander needs to asses whether the hold over time is still applicable and then check by visual means, if the wings are clear of contamination.

I'm still not clear though whether the Commander can make that decision from the Flight Deck? On a large aircraft, you can't see the wings visually from up front (unless by camera), can you?

[Rwy in Sight]

Nicholas49,

My understanding is that the commander may use all means at his/her disposal to make sure the contamination has been cleared. He may ask the FO to go inspect the wings from the cabin windows.
On the Airbus A320 family there are some lights on the side of the fuselage just to help with this task.

Regards,

Rwy in Sight

[Litebulbs]

Have a go at the course -

Aircraft Icing Training - Courses (http://aircrafticing.grc.nasa.gov/courses.html)

Also have a Google search for EASA or CAA deicing.