View Full Version : One-step/Two-step de-icing?
Does anyone have any idea what affects the decision to use one-step or two-step de-icing?
Am currently engaged in a discussion with a colleague who says that when crew arrive at the a/c and discover clear ice contamination on the wing, we can engage in a process of THREE STEP de-icing..
Stage one - Removal of ice (clean wing concept)
Stage two - Application of de-icing fluid
Stage three - Application of anti-icing fluid
It seems to me that stage three in this process is superflous as when you remove the ice everything above it goes too..
Or does this refer to the localised removal of ice? Would seem a bit silly/unsafe not to assume that if ice is present anywhere on the a/c then it COULD be present anywhere?
Sorry if this sounds confused - would appreciate some help!:ok:
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Carnage Matey!
12th Jun 2009, 14:03
One-step is deicing, two-step is anti-icing. Never heard of three step. If you are using hot de-icing fluid to remove existing ice then why bother with a second de-icing step before anti-icing? By all means check first step has removed any clear ice, and if not give it another spray with the deicing fluid, but a whole new spray? Never seen it done in Europe, the US or Canada.
Jamro
12th Jun 2009, 14:16
It sounds as if the stage one you are referring to is the manual removal of ice without using any fluid. Im assuming maybe the use of a soft broom.etc to remove heavy snow or slush before any fluid is applied.
Yup that's kinda what I thought - thanks for taking the time to reply.
It's a bit difficult to discern some of this stuff from the AEA documentation - just wanted some practical advice - thanks a lot!
punkalouver
12th Jun 2009, 18:28
I guess an important question is whether or not there is any precipitation falling anymore at this time?
Swedish Steve
13th Jun 2009, 11:21
Yes we sometimes use three steps in anticing.
Our deice trucks can deliver hot water by itself. If there is a lot of frozen deposits we will start with hot water, then type 1, then if there is any precipitation we use type 2 100pc for anticing.
We also have air blowers on the truck. This is used as the first step to remove loose snow. It is very useful around the cockpit windows which you don't want to contaminate with deice fluid.
The whole point of this is using less deice fluid for the same result. We are tasked by the airport to remove the deice fluid from the ramp, so after the aircraft has departed a sweeper goes in to collect the fluid. The less fluid the easier. The deice company is paid a fixed sum for each deicing, plus a sum per litre for deice fluid. Using snow blowers ( and sometimes brooms) before deicing proper starts can save time as we are not allowed to deice in advance, only just before departure, to stop too much fluid running down the apron drains.
One thing i have learnt after twenty years deicing in Scandinavia. There is one result, the clean wing, but many many ways to acheive it!
Thanks very much guys - you have cleared it up nicely - PPRUNE strikes again!
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