In actual flight there are small propellers rotating at the front of these "pillars". What are they? They are visible in this video.
1 Answer
Those two locations you circled out are the under-wing refuelling pods, mounted on pylons (where, I suspect, the A340 outboard engines would be).
You can find a picture of them on the A330 MRTT Wikipedia entry, under the Design section.
And those propellers on the pods are likely the ram air turbines that power the refuelling pods, according to the manufacturer:
Wing-mounted aerial refuelling pods feature a drogue refuelling system and an integral fuel boost pump which provides a fuel transfer capability up to 450USGPM (1703 Litres per minute) at 45 to 55 PSI (310 to 379 kPa). Pods operate with aircraft power or are self-powered by a Ram Air Turbine.
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3$\begingroup$ You are correct about the location of the A330 refueling pods indeed -- the A330 MRTT uses the A340 wing for precisely that reason. $\endgroup$ Oct 23, 2018 at 11:28
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2$\begingroup$ This is a very smart example of component-reuse. Put refueling pod onto the twin-engine A-330? Use the quad-engine A-340 wing. I guess this is an unexpected, positive consequence of the common development of the A-330 and A-340. $\endgroup$– Dohn JoeFeb 21, 2019 at 15:19
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