navman
RichardC10 said
My interpretation is that NTSB will be modelling the track of the aeroplane and comparing it to the ping data, as I have described previously. On the assumption that a constant heading (or a great circle) course at constant (or near constant) speed was maintained the ping data will rule out all but a small range of possible courses.
A great circle is not, in general, a line of constant heading.
Quite so, I was expressing two options that might be modelled. On the line from Malaysia to West of Australia the great circle and constant heading courses to any particular point deviate by about 30km.