Measuring the Earth's Magnetic Field

Geomagetic Suvey Aircraft

This photo showed up in the FlightAware newsletter. The airplane is a CASA C-212 Aviocar. It's set up for surveying using some kind of scientific mumbo jumbo. Looking on Fugro's website (that's the name on the tailfin) turns up nothing, though they are heavily involved in the search for the airliner that disappeared over the Indian Ocean two year's ago.

But what kind of surveying is it? Those wires strung between the prongs and the wings make me think that they are either looking for radio waves, measuring the Earth's magnetic field, or possibly measuring gravity. A little poking around turns up a picture of a similar plane on an Australian page about geomagnetic surveying. So I'm going to jump to the conclusion that this aircraft is equipped with equipment for measuring the Earth's magentic field.

Capricorn 2013 AEM TEMPEST® survey flight lines

This is what the results of an aerial magnetic survey look like.

Camel train with equipment for Edward Kidson’s magnetic survey work in Western Australia, mid-1914. Image: Carnegie Institution of Washington, Department of Terrestrial Magnetism

100 years ago they did it by hand, er, camel, courtesy Andrew Carnegie*. Andrew also sent a couple of ships out to measure magnetic fields on the ocean. The started with the Galilee, but bolts used to build the ship made accurate measurements difficult, so they built their own, the Carnegie, without using any iron or steel.

* No relation to Dale.