Heli Searching after crash?

[Kulwin Park]

Missing 206

A hi-resolution heli-mag survey will be flown by a Perth mob...
(very tight line spacing at very low-level)
Hopefully there is enough steel in a 206 to give a blip from forest canopy height.

Air Geo wrote the above in regards to the B206L missing in PNG with 2 Aussies &1 Kiwi onboard (July 2012).

With newer helicopters becoming mostly a composite structure, both with fuselage, tailbooms, and rotor blades (and even engine turbine blades) - is there newer technology to search for missing aircraft like this, below tree cover or water?? Don't most of the search aircraft base their search equipment on metallic sources?

Just wondering. And not hijacking the PNG thread.

Cheers, KP