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!
