There has been no evidence that there were new waypoints programmed in. If the last ACARS report (17:07UT) had included new waypoints, I would have expected them to be mentioned somewhere. I believe the reported stories jumped to this conclusion based on reports about specific waypoints and the the ACARS system. 1) The Military Radar Plot shows the MH370 'blips' flying directly over two waypoints (VAMPI, MEKAR), which has been used as evidence that the plane was flying a programmed route. and 2) the incorrect assertion that ACARS was manually disabled following the last update at 17:07UT, allowing the pre-programmed flight plan to be altered.- All that is known about the airplane ACARS subsystem is that it did not communicate when expected at 17:37UT. There is no evidence that can indicate why. There is no way to tell how the plane was being flown. A trained pilot could have flown over those waypoints manually, or they could have manually set directional control (Heading or Track) in the Flight Management System (FMS), or they could have entered waypoints into the FMS, and then set them as the active flight plan. Each possibility leads (or comes from) different assumptions about what the person was trying to do, when they did it, and why they did it. Unfortunately, we don't have any factual information on the actions in the cockpit, or the intentions of the people involved.
-Bill
The initial confusion, and its resolution, were used as an example of the challenges in interpreting and understanding the BFO chart. The article goes on to explain that the Doppler shift when the plane is stationary is not a simple offset, rather it is a direct result of the Doppler shift on the satellite-ground link.
The initial confusion first came up many weeks ago, when it was found that adding a simple offset to calibrate the graph for 0 speed at the gate totally messed up the rest of the graph. The bigger picture showed (as stated in the article): "the frequency shifts are much higher than they should be at the beginning of the graph, and much lower than they should be at the end." This brief confusion was quickly resolved as more and more of the frequency shift contributing components in the communications path were factored into a more complete modelling of the Doppler shifts.
Unfortunately, the best models to date still cannot explain the results we see on the BFO chart.
-Bill
Seems like a simple incorrect assumption - that the plane's route had to be differentiated between a literal North or South heading. In fact, the flight path is assumed to start on a Western Heading (Strait of Malacca) with (yet unknown) turn or turns and (yet unknown) possible directional drift due to Heading mode autopilot (Vs. Waypoint or Track mode Nav) or possible degradation of autopilot function, or basic flight stability over time.
If the 'Northern' path is presumed to be a symmetrical mirror of the Southern track flipped along the line between the plane (at a designated starting point) and the satellite - AND the satellite were stationary - then, the observed Doppler shift would be identical between the the North and South paths. Thus, for any proposed Southern path, a Northern path could be constructed with the same distances and angles (all relative to the satellite). The path would look like a mirror of the Southern path, with the mirror placed on the diagonal line between the satellite and the airplane at the starting point where the proposed paths diverge. (in other words, the two mirrored paths and the mirror would be rotated counterclockwise around the satellite, rather than literally North &. South, mirrored across the equator.)
The only way to differentiate the Northern path from the Southern path comes from the movement of the satellite. (agree on the concept. Just not yet understanding how the published results prove it.)
The satellite movement is included in the referenced modelling. (see "the MH370 Doppler derived from..." chart in the article; the blue line represents the Doppler shift on the Satellite to Earth link, the green line represents the Doppler shift on the satellite to airplane link.)
-Bill
Slashdot Mirror
There has been no evidence that there were new waypoints programmed in. If the last ACARS report (17:07UT) had included new waypoints, I would have expected them to be mentioned somewhere. I believe the reported stories jumped to this conclusion based on reports about specific waypoints and the the ACARS system. 1) The Military Radar Plot shows the MH370 'blips' flying directly over two waypoints (VAMPI, MEKAR), which has been used as evidence that the plane was flying a programmed route. and 2) the incorrect assertion that ACARS was manually disabled following the last update at 17:07UT, allowing the pre-programmed flight plan to be altered.- All that is known about the airplane ACARS subsystem is that it did not communicate when expected at 17:37UT. There is no evidence that can indicate why. There is no way to tell how the plane was being flown. A trained pilot could have flown over those waypoints manually, or they could have manually set directional control (Heading or Track) in the Flight Management System (FMS), or they could have entered waypoints into the FMS, and then set them as the active flight plan. Each possibility leads (or comes from) different assumptions about what the person was trying to do, when they did it, and why they did it. Unfortunately, we don't have any factual information on the actions in the cockpit, or the intentions of the people involved. -Bill
The initial confusion, and its resolution, were used as an example of the challenges in interpreting and understanding the BFO chart. The article goes on to explain that the Doppler shift when the plane is stationary is not a simple offset, rather it is a direct result of the Doppler shift on the satellite-ground link. The initial confusion first came up many weeks ago, when it was found that adding a simple offset to calibrate the graph for 0 speed at the gate totally messed up the rest of the graph. The bigger picture showed (as stated in the article): "the frequency shifts are much higher than they should be at the beginning of the graph, and much lower than they should be at the end." This brief confusion was quickly resolved as more and more of the frequency shift contributing components in the communications path were factored into a more complete modelling of the Doppler shifts. Unfortunately, the best models to date still cannot explain the results we see on the BFO chart. -Bill
Seems like a simple incorrect assumption - that the plane's route had to be differentiated between a literal North or South heading. In fact, the flight path is assumed to start on a Western Heading (Strait of Malacca) with (yet unknown) turn or turns and (yet unknown) possible directional drift due to Heading mode autopilot (Vs. Waypoint or Track mode Nav) or possible degradation of autopilot function, or basic flight stability over time. If the 'Northern' path is presumed to be a symmetrical mirror of the Southern track flipped along the line between the plane (at a designated starting point) and the satellite - AND the satellite were stationary - then, the observed Doppler shift would be identical between the the North and South paths. Thus, for any proposed Southern path, a Northern path could be constructed with the same distances and angles (all relative to the satellite). The path would look like a mirror of the Southern path, with the mirror placed on the diagonal line between the satellite and the airplane at the starting point where the proposed paths diverge. (in other words, the two mirrored paths and the mirror would be rotated counterclockwise around the satellite, rather than literally North &. South, mirrored across the equator.) The only way to differentiate the Northern path from the Southern path comes from the movement of the satellite. (agree on the concept. Just not yet understanding how the published results prove it.) The satellite movement is included in the referenced modelling. (see "the MH370 Doppler derived from..." chart in the article; the blue line represents the Doppler shift on the Satellite to Earth link, the green line represents the Doppler shift on the satellite to airplane link.) -Bill