Malcolm
We've chased our tails around the probability of detection, Gary thinks it should be as high as 90% for the overflight, and I've argued that it is realistically much lower, particularly for a staving, dehydrated, half dead person who would have been seeking shade back in the bush. From 400 ft up these guys were looking for an Electra more than a person.
In any case, Emily never says she saw aluminum, she only saw a rusty structure, tubular in nature, perhaps as much as 10 ft long with a round thing at the end.
where does she indicate that anything was shiny? here is a quote from her interview:
RG: You saw none of the other parts of the plane. The aluminum, the shiny parts?
ES: No, all gone. Nothing.
I believe the main wing spar - probably the largest structural member of the entire aircraft, was built of steel.
Andrew