MH370: Revised search focus
 

The West Australian newspaper is reporting today :


Fresh information suggested the jet "may have turned south" earlier than thought, Deputy Prime Minister Warren Truss said.
The detail came to light following "further refinement" of satellite data and as investigators attempted to map the plane's position during a failed attempt to contact it earlier in its flight path.


"After MH370 disappeared from the radar, Malaysia Airlines ground staff sought to make contact using a satellite phone. That was unsuccessful," he said.
"But the detailed research that's being done now has been able to... trace that phone call and help position the aircraft and the direction it was travelling."
The minister said investigators still believed MH370 was somewhere on the search zone's seventh arc, where it emitted a final satellite "handshake".
"It remains on the seventh arc - that is, there is a very, very strong view that this aircraft will be resting on the seventh arc," he said.

A further report in the Guardian today
MH370: satellite phone call revealed as Australia gives update on search | World news | theguardian.com

I am still surprised that there has been no comment in the ATSB report on any attempt to establish whether any passenger or crew mobile phones were left on by mistake.

"A further report in the Guardian today
MH370: satellite phone call revealed as Australia gives update on search..."
The article probably comes from this Communiqué:
MH370 Tripartite Meeting
Hope we have a full transcript, because the fact about "the revelation of a phone call" is not written in the Communiqué.

New Sat. phone info
 

I wonder if this lends more weight to the passenger sailboat that thought they saw the plane..............

Whilst public attention is focused on the search effort, no reports are released on the criminal investigation which continues under wraps. Is it not high time the authorities release some information as to progress on this aspect of the search for answers.

The Inmarsat Communication Log provides the following details:-
Remarks in [brackets] added by me, and a duplication of the BURUM data in the log is not reproduced here.

The unanswered call was routed via BURUM in the Netherlands. While the most relevant thing is that PERTH checked the call progress and subsequent release, which resulted in two BFO's.

That sounds great ! Now would you mind explaining the signigicance of two BFO's or even one BFO for that matter.

I'm not sure how you get 441 kt (I get ~360), but yes, that's more or less what it means. BFO 88 Hz is in line with later BFO points and it's a good indication that the turn south was completed by 18:40. I don't know if that's the point they are trying to make. This data was available from the beginning and I would've assumed that it was included in original estimates.

Back to the satcom system.There is no single high gain antenna on top center.

http://www.upload-pictures.de/bild.p...hgainJ9U9R.jpg

Photos: Boeing 777-2H6/ER Aircraft Pictures | Airliners.net

Its a bit hard to follow why the BFO analysis from the 1839 satellite call changes things now. They presumably had this information before. But the media release certainly suggests this data is being used to refine the most likely search area.

Anyway if we accept the location of the last primary contact at 1822, this fits pretty well with the first "ring" at 1825. Unlikely the plane turned south between 1822 and 1825 as this would have taken it over land.

Then a turn to the south by 1840 - not long after passing the "tip" of Sumatra.

Its hard to identify a constant course that would hit all the rings at the right time. Best fit appears to be close to due south - although the distance covered between the 2141 and 2241 rings seems a bit large.


Assuming the last ring = fuel exhaustion and crash, we know the plane flew for a defined time from last known point. We can estimate an interval of most likely speeds from the fuel load and fuel consumption. So we can estimate an interval of most likely distance covered from last known point. An earlier turn south doesn't change the known duration, nor the estimated velocity or distance covered. These stay constant.

So an earlier turn south presumably puts the crash a bit further south west along the 7th arc.

I might be totally wrong but... Although ships are required to keep adequate lookout I don't think this means they are required to have a man physically staring out to sea all the time. I believe the legal term "lookout" refers to an overall "information collecting process" that can include staring at radar. I can well imagine that particularly at night that's all they do.

So unless the aircraft appeared and was recorded on radar as it impacted I doubt anyone saw anything. Might be different if it was on fire though?

We have a bunch of packets at 18:28 with BFOs consistent with being on the northwesterly heading.

There are other possible interpretations - BFOs are strongly affected by vertical speed, so it could be that it was headed south while climbing (there are irregularities in 18:25 .. 18:28 period indicative of climbing) - but the simplest one is that the turn took place after 18:28 and before 18:40.

The new predicted location is still around the seventh ping arc.
The new location is still in the area being surveyed for the Australian government.
The new location is a bit further south-west than the previous one, based on new analysis of the data.

What, exactly, is supposed to look clueless about that?

I agree Richard C10. Up to a point. That is probably how you would like to analyse the satellite data and model the possible tracks. As a purely scientific exercise.

However real life is always more messy, and there were many other factors and agendas going on.
1. Inmarsat was breaking new ground here. The BTO analysis came out first, and this data was easily understood and was presumably readily accepted. So we had the north and the south arcs. The south arc was initially seen as more likely as no one (especially India) had observed the plane over the northern arc.
2. As soon as the south Indian ocean was identified as a possible area, everyone with a satellite started finding debris.
3. Then the BFO analysis came out. This was far more complex than the BTO analysis. It took time, It required corroboration by independent scientists. And there was likely a degree of circumspection in various quarters. None the less, the BFO analysis identified a likely area - not so far away from the area now thought to be most promising.
4. Then came an air search. Due to all the delays, it was already very late when this was started. Even if debris had been found, it would have been difficult to backtrack. However it was the best hope at the time, and so began a multinational air search that was complicated by the distance from land and poor weather. This was only called off when it was clear the delay meant that backtracking would be futile.
5. At some point, the search area moved a long way NE along the arc. It has never been made clear why this happened. People have speculated that a UK submarine detected something that could have been a pinger, but we will likely never know the explanation for this. Ships went to this new area and seemed to have immediate success finding the pinger. It turned out there was no pinger and the noise heard came from the ship. Yes that was all a bit of a screw up.
6. Hence back to the BFO data. The highest probability area was calculated on the basis of detailed calculations and utilising different models, and is fairly close to the earlier area. So they started to map the ocean floor (this area is practically unknown) in preparation for another search.
7. They have now incorporated information from an unanswered call to help refine the search area. Presumably this data pushes the search area a little further SW.

On top of all this has been significant political and diplomatic pressures. There was certainly an initial reluctance on the part of the Malaysians to tell all they knew. The Australian Prime Minister was under pressure, and jumped the gun based on satellite photos of debris.

Its not been perfect. Far from it. Things are always easy in retrospect.

In fairness, it has probably been about as good as could have reasonably been expected in the real world. This is especially true given this event was unprecedented, and given we have been using technology in novel ways.

I do not agree with that at all, Inmarsat had no obligation to release any of this data (or even collect it). The fact they have done so has resulted in the only evidence we have to suggest a possible final location for the aircraft. They should be applauded for the hard work they have done thus far, not lambasted for not releasing the data (which, by the way, I thought they had?) for internet amateurs to pick over.

That's because they're only mapping it at this point. I doubt anyone involved in the search expects anything to be found until they go back with high-res sonar.

Again, the new location is inside the area previously chosen for the next phase of the search. The original ULB search area was also inside that area, and the ship searching for the ULBs was heading there when it heard what turned out to the spurious signals and stopped to investigate.

None of this satellite data was ever designed to be used to locate a missing aircraft. The BTO was thought to be a means of extracting some information to help locate an aircraft in an incident like AF447 where we already knew the approximate area, but not to find one that had vanished without trace. No-one expected to find useful information in the BFO data, because the aircraft was supposed to correct for frequency offsets, so this has all come from reverse-engineering the corrections made.

And all of the detailed position estimates are heavily reliant on knowing where the aircraft turned south. Anything that changes the estimate of that position inevitably changes the final position.

So the odds are good that it won't be found exactly where they're now predicting, because there are so many other variables that can only be estimated. But it's the best place to start, to minimize the amount of time spent searching the area they're now mapping.

We should all remember that the disappearance of this aircraft is the subject of a criminal investigation and as such, not all information available to the investigating team is available to the public.

The investigating team and their advisors may look ill informed but it is wise to remember that they probably have more information than we do.

"We should all remember that the disappearance of this aircraft is the subject of a criminal investigation and as such, not all information available to the investigating team is available to the public.

The investigating team and their advisors may look ill informed but it is wise to remember that they probably have more information than we do."

then it would be fair from them to say "we have some informations that we can not disclose at this point", not look totally inept calculating numbers that at first aren't reliable enough to prove anything

It's not an easy task. Trying to determine ground speed and heading over many hours from a handful of values for velocity away from a satellite.

Agree that vertical velocity will influence velocity relative to satellite. But not sufficient to produce a false (of to conceal a real) major heading change.

To me it seems very good news if we have been able to significantly narrow down the time when the aircraft turned south.

Why, they don't owe you anything and you have no 'Need to know".