Another couple of good graphics on MH370 search area (intercestion of arcs and maximum distance)

[morningfog]

This one is good, because it give the intersection of the last signal (the arcs) and the maximum distance it could have traveled from the last known position. Assuming that the plane did not land an refuel before the arc ping, it would run out of fuel, land or crash somewhere near these intersections. What we don't know is, the direction, speed or elevation at the arc ping.




And, here is another graphic giving perspective to the search area (however they defined it):

[NightWatcher]

1. It's in BENGHAZI!!!

[lumberjack_jeff]

2. I don't understand "the arc ping intersection"

are they saying that the satellite signal shows the bearing or that it shows the distance? In other words, was the plane somewhere in one of two pie-shaped areas or is it somewhere on one of those two arcs?

Also, wouldn't they know the time of that ping? Knowing the time elapsed between the last radar contact and the ping and knowing the flight speed would put another circle on the map.

[FarCenter]

3. My guess would be that the arcs are the line on the globe corresponding to a particular delay

By measuring the delay between the transmission of the ping and the reception of the reply, you know how far the plane is from the satellite. Knowing only distance you then can compute the circle on the earth's surface that is that far away. Unlike the pictures we see, there will be some uncertainty in the delay, and hence the distance. I'd think that the arcs are actually fairly wide bands.

What the maps also don't show is that if the plane isn't flying exactly along the circle of constant delay, successive pings will have different delay and hence locate the plane in different bands at different times.

[muriel_volestrangler]

5. Someone in the satellite industry thinks your guess is right

See http://tmfassociates.com/blog/2014/03/17/locating-satellite-pings/

[FarCenter]

11. Thanks for the link.

[morningfog]

7. It was somewhere on the arcs. It showed the distance from the satellite only.

They knew the time of the ping, 8:11 AM. But they don't know the direction the place was heading, or the speed.

[lumberjack_jeff]

10. That's roughly 6 hours after they lost contact, right?

6 hours at 650mph is either Kazakhstan or deep in the South Indian Ocean, right? One assumes that there's little reason to hijack a plane to Antarctica.

[Voice for Peace]

4. my guess is the people in the maldives did see it, shortly before it ran out of fuel

and landed deep in the ocean.

http://timesofindia.indiatimes.com/world/south-asia/Missing-Malaysian-jetliner-Maldives-islanders-saw-low-flying-plane/articleshow/32251148.cms

[muriel_volestrangler]

6. The Maldives are too far away from the arcs for it to fly to there and then the arcs

The Maldives are 73 degrees E, 3 degrees N - about 3 quarters of the way from the last known radar contact to the point directly beneath the satellite. If it went that way, it would have to go even farther back to reach the arcs.

[Voice for Peace]

13. I wonder why they'd make something like this up?

The military in the Maldives, a remote Indian Ocean island nation, confirmed to Malaysia that reports of a sighting of the plane by villagers there were "not true," the Malaysian defense minister said.

[muriel_volestrangler]

14. They saw another plane, perhaps

The direction they described (north to south) would not be a plane coming from the Malacca Strait - it would have had to turn 90 degrees for that. If the satellite contact wasn't known, it would seem more likely to be the Malaysian plane - the plane might have turned to attempt to land somewhere. But if the data from Inmarsat is accurate, it doesn't really fit. But another plane, with a bit of red and white on it, might be it. The details could be wrong, too - if it is a remote place, they may not be used to describing large planes.

[Voice for Peace]

16. all good points, thanks

I love having so many brains here on the forum:
collective madness sometimes, but a much
more rounded and informed perspective.

[FightingIrish]

8. This is driving me crazy.

The media keeps referring to the satellite arcs as “corridors” as though they represent some kind of track the plane would have followed. They are nothing more than “lines of position” (more correctly “arcs of position”) representing all the possible points equidistant from a satellite at the instant of one of the pings or “handshakes”. Most of the circle of equidistance is disregarded due to distance from the last point of contact or range of the aircraft. If you drew another circle showing the distance the plane would likely have traveled between the last radar sighting and the instant of the ping, you should have two overlapping circles and where they intersect would be two possible, although ambiguous, points of probability. In the old days when we relied on Loran for navigation we often only had a single Loran line (a parabola) to determine our position. Where we were along that line was the big question. If we were lucky we had an intersecting line of position from a celestial observation.

[morningfog]

9. I agree, but the first graphic is finally getting closer to helpful

by showing the intersection. The thing is, there are still too many unknowns for the intersection to be terribly helpful. It can help exclude some points beyond the maximum distance given the fuel.

However, that assumes that the plane did not refuel. That is a reasonable, if not likely, presumption, but still an unknown.

I think the best way to go about this would be to exclude as much as possible. Assume no refueling, everything outside the circle is gone. The points along the arcs in China and India should probably be excluded. I still don't see the southern arc providing a helpful reference point, given the previous known trajectory.

[FightingIrish]

12. This is another way to look at it

This graphic is not intended to show the plane's location but a more logical method to determine it. You would need to know the time and location of the last radar position, the time of the ping and guess at the likely ground speed. The possible tracks would be the lines between the radar contact and the intersections of the two circles. This assumes that the ping occurred after the radar position which may not be the case. It also assumes that the plane did not change course between the two events. This confirms my position that they now can be reasonably certain that they don't know shit.

[magical thyme]

15. that's ignoring military radar that some countries had on what is believed to be that flight

Thailand didn't give up the radar information until yesterday. It shows an unidentified plane in the appropriate time frame and possibly that flight, headed back toward Kuala Lumpur along the Malaysian Straight and then turning west toward a city called Butterworth.

Butterworth has a military airport with an 11,000 foot runway with sea approacha. It matches the pilot with the electrical fire theory, except suggests they initially headed back toward their takeoff point and then changed toward a different airport than he proposed. It may also explain why they are concentrating their search toward the southwest and why Australia joined it yesterday.

And Malaysia has received military radar from some other countries that they are unable to release. At least some countries in the area have been unwilling and/or slow to share information that they believe could compromise their security.

The combined intersection of all the data Malaysia has -- which is not shared with us -- may significantly shrink the possible crash (or landing) sites. There is a reason why they