De-ice TYPE I fluid

[Driver 170]

I’m interested in knowing what is the usual FLUID / WATER ration when carrying out a Step 1 de-icing if there is contamination on the upper wings (hoar frost) during the night but NO precipitation falling?

Would 100/0 be good enough or 75/25 ?

Also how many litres does it take roughly to remove all contaminates from a 737 NG wing?

[Flying Wild]

I’m interested in knowing what is the usual FLUID / WATER ration when carrying out a Step 1 de-icing if there is contamination on the upper wings (hoar frost) during the night but NO precipitation falling?

Would 100/0 be good enough or 75/25 ?

Also how many litres does it take roughly to remove all contaminates from a 737 NG wing?

Guidelines simply state that the Type 1 Fluid/Water mixture must be such that the freezing point of the mixture is at least 10C below the OAT.

You'd probably be looking at 2-300 litres at a guess. Depends on the contaminant and the rig operator.

In the UK you're more likely to use Type 2 or Type 4 fluid.

[Driver 170]

Guidelines simply state that the Type 1 Fluid/Water mixture must be such that the freezing point of the mixture is at least 10C below the OAT.

You'd probably be looking at 2-300 litres at a guess. Depends on the contaminant and the rig operator.

In the UK you're more likely to use Type 2 or Type 4 fluid.

Is there anyway i can find out what mixture to use for a freezing point of 10c below OAT?

I do use this app called DeIcing holdover app for IOS.

if using Type 4 Fluid can this be used as a Step 1? Reason i ask, I was on a EZY flight from EDI last Saturday morning at 06:45 and during takeoff roll - green fluid (type 4) came off the wings at high speed as it should. During boarding i seen no de-ice truck. So would this have been done early morning by ground engineers?

[tubby linton]

Have a look at
https://www.faa.gov/regulations_policies/orders_notices/index.cfm/go/document.information/documentID/1036429

and also
https://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/media/FAA_2019-20_HoldoverTables.pdf

[ivor toolbox]

Is there anyway i can find out what mixture to use for a freezing point of 10c below OAT?

I do use this app called DeIcing holdover app for IOS.

if using Type 4 Fluid can this be used as a Step 1? Reason i ask, I was on a EZY flight from EDI last Saturday morning at 06:45 and during takeoff roll - green fluid (type 4) came off the wings at high speed as it should. During boarding i seen no de-ice truck. So would this have been done early morning by ground engineers?


​​​​​​You can do a combined step1 (de icing) and step 2 (anti icing) if weather conditions and type of fluid mix permit. Type 1 fluid use has largely been discontinued to to its negative impact on environment, and likewise type 3, due to its corrosive properties to modern carbon fibre aircraft brakes. Hold over time with a type 2 or type 4 fluid can be up to 5 hours at typical 75/25 mix used in UK, so, yes, in your case the deicing would have been done earlier.

https://www.skybrary.aero/index.php/Holdover_Time_(HOT)

Ttfn

[Driver 170]

Great information, thanks.

[Intruder]

From our Deicing Manual:Type I fluids are used for both deicing and anti-icing. It is primarily used heated as a deicing fluid. It has limited effectiveness when used for anti-icing. Type I fluids which use ethylene glycol as a freezing point depressant may be used undiluted for anti-icing. Type I fluids which use propylene glycol as a freezing point depressant must not be used stronger than 60 percent deicer.