DC10 engine anti-icing
 

Can anyone give me a conclusive answer to either of these two questions regarding CF6 engines and the DC10-30.
1. Can you clarify when engine antiice is required with respect to the 3 degree split between oat and dew point. I was told that some crews interpret this as applying even when the OAT IS 30 degrees celsius and dew point is say 27 degrees celsuis. I'm a bit suspicious of this.
2. In the descent with idle thrust and in visible moisture with the TAT above 6 degrees celsius, what are the engine antiice requirements.
Now I know what I would d o for the above, personally, but can I have a manufacturers definition as to the requirement, please.

Thanks for your help guys.

POINT1:with oat less than 10C AND 3 degrees or less btw oat and dew point ANTI ICE ON even on a sunny day 10km vis and no visible moisture
POINT2:A/I on

DC10 engine anti-ice
 

If i remember correctly (been on the Ten 20 years ago), Douglas manual stated: "Engine anti-ice must be selected ON if icing condition is encountered or anticipated".
The manual define icing condition as:
OAT(on ground)/TAT (inflight) of 6 deg or less, with:
a.visible moisture or
b.temperature and dewpoint differ by 3 deg or more

terainpullup's memory is good! The OAT/TAT has to be + 6 C or below for engine anti-icing considerations on the CF6-50.

At least while it is installed on a Douglas. The same engine has different limits depending on the airframe manufacturer. Go figure.

Another fascinating DC-10 anti-icing fact. The No. 1 VHF antenna (the one on top of the fuselage) is anti-iced by hot air, which is activated by selecting the No. 2 engine anti-ice on. (No. 2 engine is the one in the fin, by the way, a fact which sometimes astonishes some people.) However, the source of the bleed air to the antenna is No. 3 engine, because it's closer.

Yes, it's a favourite question in the technical exam. :)

Then, of course, you get evil training captains in the sim, failing No. 3 engine, in icing conditions. Soon after - gosh wot a surprise - bang goes No. 2 because the VHF antenna has now shed a load of ice down it and wrecked the compressor. Now we're into the "Two Engines Inoperative Checklist" and all the fun that goes with it ... especially that hideous chart!

Er ... I've suddenly reminded myself why I packed in flying the jolly old "Death Cruiser." Dull it wasn't! :bored: