It was in 1994 that I and Don Angwin sat down with the CEO of GeoScience in Perth and discussed how it could be done. He assured Don and I that with the technology he had then that he could find the ferrous in the engines to a depth of 85 feet by a chopper towing a bird over the trees. He offered the data processing for free if we could raise the required 100K as it was then. Was that all pure BS ?
Since then technology has improved by leaps and bounds from what I read and the chopper with a boom can get closer to the trees. Data processing apparently now consists of removing the hard drive from the gear, taking it to the hotel room plugging it into a laptop and we get the Lat/Long in the morning.
I have spoken with Fugro on a few occasions. I say "I" have spoken with them, they seem not to want to talk until I show them the dough. This is broadly speaking along the same line as you infer.
Which company were you with, the former or the latter ?
There is about 500 lbs. of ferrous in each engine which is the crankshaft, the bob-weights, the con-rods, the clinder barrels and heads. Two concentrated blobs about 30 metres apart. There are also the ferrous parts in the landing gear struts and steel tubing of the mounts.
None of that would show ? What about the Magnetometer work done in PNG in the sixties and seventies where "it is said" WWII wrecks showed up as pinpoints on the scans ? BS too ?
David....I have no wish to "rain on your parade " and would be interested in assisting you in any way, but the reality of using currently available geophysics in the context you describe is still not feasible.
To answer your questions;
I had associations with Geoscience years ago and worked for Fugro for five years or so after they took over the company I worked for.
World Geoscience never let reality stand in the way for a fast buck and their offer to process for free was meaningless since about five hours work was all that would have been required and they would have padded that into their flying costs anyway....modus operandi for them.
Yes things have progressed in leaps and bounds, but not far enough.
A "bird mounted" magnetic gradiometer is still the best technology to find the magnetic components, but unless you know within a square kilometer (for sure) where the aircraft was, the cost of doing so would be horrendous.
Of course, if you knew that, then finding it by a ground party would be more certain, quicker and cheaper.
The problem re the ferrous components is that they don't have a lot of permanent magnetic properties and hence little signature.
That's why it's sister ship the Lockheed Hudson made such a good magnetic sensing platforms in the fifties.
In fact, with a 100ft towline, the Hudson virtually became magnetically invisible to the instrumentation!
The Hudson as I recall was even larger than the Electra.
Re the WWII wrecks, well I did much of those surveys and the only ones I ever saw were the landing craft on the beaches which did show up (many tons of steel).
To my knowledge no aircraft have been found by the magnetics other than those already known about.
We flew over a B25 at Madang that was just under water, and if we didn't know it was there we would have missed it completely on the magnetic readings.
I could go on, but would be happy to talk to you regarding the issues if you wish to PM me.