A320 No Tail Antiicing
 

Hello experts,

What is the explanation on lack of tail anti / de icing on A320. i presume that horizontal tail is not impacted directly by supercooled droplets due to wing downwash, but what about the vertical tail leading edge?

Also I am wandering what are water drain outlets for - when is water draining through them? They are heated?

Complies with the icing certification requirement for both maximum continuous and intermittent maximum icing conditions without deicing of these surfaces.
Not unusual for jet transports to have some surfaces or parts of surfaces without anti ice / deice fitted.

the galleys and toilet sink have waste water drain masts which are electrically heated.

And just to be clear, in addition to the aircraft being demonstrated compliant, as zzuf says, this will be with a significant ice shape on both the horizontal and vertical tails. This urban myth that there are aircraft where the tail does not catch ice is exactly that, a complete myth. Indeed the tail, being a small LE radius and thus "sharper" than the wing, is actually more efficient at building ice than the wing.

Just because it isn't anti-iced does NOT mean it will be free of ice anyway.

If I understood you well:

- Ice IS forming on LE of tailplanes and fin, but is not having large detrimental effect on aerodynamics ? How is this possible?

- Water is drained during flight (otherwise why heating) through the masts, from the sink.

In practice you will indeed find the horizontal tail to be the most affected by ice accretion! When we have to de-ice on the ground after a flight through icing conditions it is usually due to the stabilizer being iced up, and not the unheated inner slats!

Icing certification requires demonstration in both cumulo cloud and strato cloud icing conditions. These conditions are defined by the liquid water content of the cloud and the water droplet size. Strato clouds are considered long term encounters, cumulo clouds to be intermittent encounters. There are exposure times defined in the certification requirements. This information enables the design office to calculate the shape of the ice accretion.
Flight test will be carried out to ensure the aircraft handling complies with certification standards with the critical ice shapes fitted to the non anti ice/deiced surfaces.
It can be a frustrating and time consuming exercise searching for "certification standard" clouds so simulated ice shapes may be used at times, but like airborne water spray rigs they don't replace exposure to natural icing for certification.
Of course there is much more to icing certification than the above.

Ice IS forming.

Ice IS in fact affecting the aerodynamics. (Of course)

The aircraft has been designed to account for that. (Simplistically, the tail is over-sized to compensate for reduced effectiveness when ice forms; it's easier/cheaper/simpler to make the tail a bit bigger and take a weight penalty than to install a whole extra anti-icing system on the tail, which is why that's the typical approach for higher speed aircraft)

The A330 777 744 and 737 all don't have de-ice/anti-ice on the tail surfaces.

That goes for the 727, 757 and 767 as well.

If so, can we change the thread title please?

The list of aircraft WITHOUT tail anti-/de-icing is pretty long, I'm not sure we could list them all in a thread title. (I believe there's a character limit applicable to titles)

The original question was about the A320, the title seems valid to me.

I think the last commercial aircraft I worked on that had tail plane de-icing was the HS Trident - none of the Boeings, L1011, or Airbus had it. The only reason I remember the Trident horizontal stab. De-icing is that the system incorporated a rubber flexible joint known to all and sundry as 'the Donkeys Dick'. Probably the most obscene looking aircraft component in history. The designer must have had a sense of humour.

The MD80 had de-icing on the horizontal stab, another rare exception.

Fokker F70/100 have stab and vertical fin anti icing.One of the reaso why that thing is always short of bleed air :sad: