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betaboy
25th Nov 2004, 00:17
Does anyone have any definitive reasons why the tail of the B747-400 does not require any sort of heating/ice protection?

Also, is the A340 similarly unprotected?

Max Angle
25th Nov 2004, 11:48
I don't think there are any current jet transports that have ice protection on the tail surfaces, could be wrong but none of the Airbus or Boeing aircraft I know about have it.

grease7
25th Nov 2004, 11:53
Logically thinking it is because they don't provide lift, like the wings do. If the ice forms there the characteristicts of the wing are gone and the wing could stall. The tail section is there to stabilize the aircraft hence it's called the horizontal and vertical stabilizer.

I think this is the big reason but i guess there a probably more and will be posted on this thread.

alf5071h
25th Nov 2004, 14:58
grease7 – your logic is way off the mark! The tail-plane provides aerodynamic force – lift; often in the opposite sense to conventional wing lift. If tail lift is lost due to icing, particularly on smaller aircraft then it may result in a hazardous tail-plane stall and loss of control.

Lack of anti icing on the tails of larger aircraft may be associated with the shape of the tail plane; thicker aerodynamic surfaces with larger leading edge radius do not accrete ice as easily / quickly as thin sections or those with relatively sharp leading edges. In addition, the overall airflow pattern would be considered as well as the effect of any ice on the control surface. The use of powered controls and slab tail may also affect the aerodynamic performance in icing.

Astra driver
25th Nov 2004, 16:24
alf5071h,

I agree with your statements. It is interesting as to why the 74' and 340 lack tailplane anti-ice.

When I go to Recurrent training on the Astra we frequently discuss and practice tail icing / stall events. They are somewhat insidious in that a tail stall manifests itself in the sameway as a wing stall yet the recovery procedure is opposite. (Pull back on yoke as opposed to push fwd.) The key to the correct recovery being to be able to recognize the circumstances under which the stall occurred.

I would be curious as to exactly why the larger transports do not require the tail anti/de-ice.

TopBunk
25th Nov 2004, 17:17
the 74' and 340 lack tailplane anti-ice

... and the A320 family, the B737 family, B757, B767, B777 [and no doubt many others].

oldebloke
26th Nov 2004, 01:40
The reason ,as stated before in this forum ,is that Boeing and Airbus provide enough area(stabalizer) to carry the load (ice)whereas Douglas utilized smaller surface stabs requiring deicing(DC8/9and MD11)...:ok:

grease7
26th Nov 2004, 09:07
alf5701h Yeah you are right my logic was a bit offline, but then i am not a pilot:}

betaboy
28th Nov 2004, 05:29
Are any speed adjustments required on the A340 or 747 (e.g. Ref + 10) when you know you are landing with ice on the tail? I know this is a factor on, say, the 737.

Shore Guy
28th Nov 2004, 12:22
Another area in transport (or any) aircraft that is not protected are the flaps. While we all try to avoid icing conditions while configured, sometimes it is just not possible. And there can be consequences.

Too large to post here, but ask your Boeing rep for Flight Operations Technical Bulletin 767-63, “Airframe Buffet in Icing Conditions” (ref: 767-300 aircraft), or check out:

http://www.smartcockpit.com

(A great site)……hit “767”, then under “Instructors Corner”, check out “Icing Buffet”.

I’ve experienced this, and it really got our attention……