Saturday, March 03, 2018

Airplane Hunting

 Bristol Beaufighter firing rockets
As Chairman of The Swale Search and Recovery (metal detecting) Club I was approached recently by an up-and-coming air museum to help look for wreckage of a WWII Bristol Beaufighter that had crashed on a local muddy foreshore during a training exercise. It was believed, or hoped, that there was a substantial amount of wreckage remaining although little had been seen above ground for some considerable time.
For the initial search I organised a party of half a dozen metal detectorists to search the area, at low tide, around where the plane was thought to have crashed, which the museum assistant marked with a clump of stakes. While plenty of spent ammunition was found, not one single piece related to the plane emerged, although the tide had not been as low as we would have liked.
For the second search, at a predicted lower tide, I took my aura camera and long lens instead of a metal detector and let the others carry on metal detecting while I stood at the marker stakes and proceeded to photograph the exposed foreshore piece by piece in a one hundred and eighty degree arc around the stakes. On dry land I could have linked the camera to a laptop and analysed the photos on the spot, but out on a tidal foreshore, it would not be a good idea so I just used the camera and would analyse the photos at home later. Although there were a few permanent seamarks to help frame the photos, it was mainly guesswork where I was pointing the camera as featureless foreshore and open sea all looks the same. With the benefit of hindsight I could have used a compass and obtained a bearing for each photo. An assistant to use the compass to line me up for the photo and to note the readings would be a great help. Again the detectorists found only spent ammunition and nothing that could be specifically related to the plane.
I downloaded the photos at home and enhanced them with Arcsoft Photostudio. I was pleased to see that there were areas showing an orange aura (top photo) as well as areas showing no aura (bottom photo). I assumed I had taken photos fairly evenly around the arc and nominally assigned compass points to the aura photos. That gave me one search area approx North to Nor’-Nor’-East and another due South.


Armed with this information I organised another search, although the detecting party had now reduced to three only. Two of us went searching to the North and one to the South. We did not know how far away the targets were but guessed they would be less than 200 yards (or metres) as that was the optimum range I had been able to pick up a large target in the past. It would be possible to walk in the direction of the auras with the camera, particularly if there were compass bearings, and to re-photograph them at say ten-yard or metre intervals, which could be measured by pacing or a surveyors tape. Of course this would require another at-home analysis session to determine at which point the aura image is lost and determine that the target would lie between there and the previous ten-yard point where the image was captured. A further session on the site would be required to make the final location and recovery. Nevertheless we had some results. The South searching detectorist recovered a part of the plane’s ammunition box, meanwhile the two of us searching northwards discovered a 60lb rocket each, part of the plane’s arsenal. I also recovered a small piece of aircraft battery. So by using aura photography, we had actually started finding what we were looking for as well as defining where to look on future searches.
Part of ammunition box

One of the rockets recovered in two parts (dummy warhead at bottom) and minus fins
A Beaufighter being armed with rockets