Runway "wet,wet,wet with anti icing fluid"

[PilotJames]

If you hear this on the ATIS with OAT less than 10 degrees do you stick the engine anti ice on or not?
(Assuming no other moisture from fog or rain etc)
Seems to be a difference of opinion at my outfit

A320

[Tu.114]

What type?

[PilotJames]

What type?

Edited original post :)

[speedrestriction]

You talking about Manchester by any chance? In my experience it usually damp, but with a shiny glaze of anti-ice fluid. Usually not anything akin to say, for example, a rain shower having passed through. There is no way that there is anything likely to lead to ice accretion on the intake or fan blades. However, rules are rules.......Common sense would say no issue, rules may dictate otherwise. Load an extra 20kg of fuel, stick on the anti-ice and let the company worry about it.

[FlightDetent]

In general, no. As per manufacturer's guidance:
1291

The decision on a particular day may differ, though.

[PilotJames]

I guess as you say it's strictly not part of the criteria written.
If the apron and taxiways are wet that means you will have it on anyway for the taxi and takeoff.
I haven't heard it anywhere else other than manch.

[PEI_3721]

I would be more interested in the runway braking action.
What end of the the 'wet' scale of reduced friction is runway de-anti-icing fluid?
I assume that we are considering runway surface treatment and not fluid shed from aircraft during takeoff.

[FlightDetent]

If the apron and taxiways are wet that means you will have it on anyway for the taxi and takeoff.And what makes you say that? (my underlining)

[PilotJames]

And what makes you say that? (my underlining)

If the OAT is less than 10degrees and the taxiways are wet (or have standing water) then it would be prudent to stick the anti ice on as you have to taxi to the runway.

[FlightDetent]

Ok, understood. Just that formally wet is very different by definition from standing water in the realm of tkof perf calculations. That's why they do not say "wet" in the paragraph I quoted and thus simply wet does not constitute icing conditions.

[PilotJames]

Ok, understood. Just that formally wet is very different by definition from standing water in the realm of tkof perf calculations. That's why they do not say "wet" in the paragraph I quoted and thus simply wet does not constitute icing conditions.

You are completely correct.
Just out of interest does your airline not turn on the anti-ice if the taxiways and runways are wet (not standing water), just wet (10 degrees or less).
Mine does maybe as belt and braces, I understand that is not strictly what's written.

[Piltdown Man]

If for this temperature your books say wet = engine anti-ice on, then do so. I think the assumption is that wet = 100% water, not a mixture on anti-icing fluid and water. But so what, stick it on and be happy you've ticked a box. It's not as if this prevents you from lifting your assigned payload is it?

PM

[FlightDetent]

PJ: See here (http://www.pprune.org/tech-log/587181-runway-wet-wet-wet-anti-icing-fluid.html#post9582812) but all three senteces, pls. We're a frequent operator in the north-east quadrant of Vienna, going to all of the capitals within 4 hrs radius. And I'd say there's no need or practical benefit to turn it on in the exact conditions you describe.

Caution before engaging in a heated argument somewhere: WET for tkof perf purpouses embraces up to 3 mm of water, only then it becomes water-contaminated. For practical E-AI purpouses, standing water they warn against comes much sooner than 3 mm - I'd say.

Look outside, use it when you need it or the book tells you so, and do not load other people's guns when they aim at you. :)

[PEI_3721]

Whilst engine anti ice might not degrade the takeoff performance by any significant amount, reduced runway braking action could have a far greater effect.
First reaction to a runway condition report with a caveat 'wet with ...' is to treat it like 'slippery when wet' which reduces the braking action.
Does anyone have information on the effect of runway deicing fluid on braking action; considering different runway surfaces, or fluid on top of rubber deposits?

Wet, not standing water or flooded, is considered as a single category. However, there is a significant variation in braking action within the wet category depending on water depth (<3mm), and the runway surface and maintenance condition.
Consider 2.9mm water, or 0.01mu above the maintenance level, how might de icing fluid affect these aspects.
Also, in many documents water is discussed as a 'contaminant', but not significant for performance <3mm.
Runway deicing fluid is a 'contaminant', thus requires additional consideration.