[Drago]

Unless they somehow “triangulated” the maintenance pings(doubtful), they wouldn’t give a heading, just time. How did they arrive at a heading towards the South Indian Ocean? (~1400 miles SW of Perth) I don’t think I read anything about how the NTSB?? arrived at a heading.

[Meet the New Boss]

I believe the arcs were indeed arrived at by triangulation from two Inmarsat satellites.

It would be at the edge of the coverage range for the second satellite, but it appears from the arcs that they must have recovered signals received by a second satellite.

Knowing the time the pings were issued (e.g., 6:11:0000, 7:11:0000, 8:11:0000) and the time the pings were received by each satellite (e.g., 6:11:0002, 7:11:0008, 8:11:0013) they can compute an approximate distance x from satellite 1 and an approximate distance y from satellite 2.

The problem is the satellites sit over the equator. Therefore there are two solutions to the problem object Z is distance x from satellite 1 and y from satellite 2. One is to the north of the equator, and one is to the south of the equator.