View Full Version : Wing anti-icing
Genghis
16th May 2002, 08:57
A general question - on what proportion of flights is wing anti-icing typically used for typical wide-body operations?
All thoughts welcome!
Oxford1G
16th May 2002, 10:34
Dear Genghis,
I can only speak for the DC-10 and the B767.
We would use airframe as well as engine anti-ice for all take-off's in icing conditions.
In the air, in icing conditions, if we found sign's of ice build up, ie on the wiper blades, we would use airframe anti-ice as well as engine anti-ice.
Boeing and MD, also had different definitions for icing conditions.
The % of the flight in icing conditions is difficult to define. You may fly from the UK in the winter and not need it at all. You could also fly from Singapore to Sydney, and due to the ITCZ, be IMC at FL 290 and due to the high temperature require engine anti-ice, as well as airframe.
Hope this helps.
There is very little in the modern jets that is actually covered by the wing anti Ice.
On the Airbus's its the outter half of the wing only.
It is very rare to use wing anti Ice. and techniques on its use are changing again. In order to prevent runback and refreazing the wing are now recommended to be cycled much like the old pneumatic boots. Automatic Wing A/I does that for you on several diff kinds of jets I believe. 3 engine aicraft like the 727 are the exception because they have to run Wing Anti Ice anytime you use engine anti Ice to protect against Ice accretion on the number 2 VHF antenna which then sheds into the number 2 engine.
Engine anti Ice is used anytime there is visiable moisture and from +10 TAT to -40 SAT give or take a few degrees.
Cheers
Wino
Intruder
16th May 2002, 18:29
I have not ever used wing anti-ice in almost 4 years flying the 747-400.
It is listed in the FHB as "ineffective" with the flaps down, so it is useless for takeoff and landing. Further, we can't legally take off with any ice or snow on the wings anyhow.
In the times the ice detectors have alerted us, I have not seen sufficient ice on the wing LE to bother turning it on.
OTOH, we use nacelle (engine) anti-ice quite often...