Flashes from my memory.
Lost a/c was a Pawnee
I have a feeling the crew assisting were flying a DC10, which could make them Air N-Z and the time maybe early 80s.
In rough terms an arm held outstretched with the fist clenched, each knuckle subtends an angle of about 1 degree and provides an approximate way of measuring the sun's elevation. Check difference of elevation between lost a/c and seeking a/c at same time this will give a indication of difference of lattitude, you have one position line, difference of sun's azimuth will give differnce of longitude. all very approximate but in that case it worked. A great bit of work from the ANZ crew.I think they were recognised by the Institute of Navigation.