suninmyeyes: That is without doubt the most interesting post I've read. Why the oscillation?

If I remember correctly, the aircraft would not have run out of fuel at the point where it crossed the final ping arc on the earlier estimates; didn't they say it had 30 minutes to an hour of fuel left?

It may be that the new estimate now has it running out of fuel on the final arc, which seems likely to be the case.

Thats sort of what I was presuming, the final position derived position area is still the same, but the amount of time possible after that point has decreased.

They flew faster than expected during the first 2 hours. Which means that they had less fuel left than expected. Which means that they had to fly slower than expected for the remaining 6-ish hours if they were to stay airborne for the duration.

Also, since the last known position (just under 2 hours into the flight, 18:22 UTC) is fixed by the radar, the fact that they flew faster before that point does not put them any further out.

The media wording about the increased speed and fuel usage is particularly bad.

The original explanation of the latest new crash position calculation, that I believe, explains the reduced distance travelled - is that the aircraft initially used more fuel than originally estimated, because revised calculations of the flight path, speed and height, in the sector between where the aircraft initially diverted from its flight plan, to the point where it was last sighted on radar, showed an increased fuel burn over initial calculations.

This then left less fuel to burn between last radar sighting point, and fuel starvation point. The new calculations obviously pick up increased flight phugoid movements or perhaps even throttle position changes.
Spare a thought for those doing the calculations, with so little real information from the flight deck.

Nothing to do with arcs.
Pure physics

Speed x time = distance

Simple as that

For it to have flown a shorter distance then either speed or time MUST be lower.

Buttrck

Are you asking....
If he is going faster, then how come he went "less far".....in the same amount of time.

Its a confusing post (the arc's bit is irrelevant to the equation, its only relevant to the distance traveled or the final location).

If the aircraft traveled faster, then it would have run out of fuel earlier, so the "time" part of the equation IS shorter (lower).

I find it very hard to understand why almost a whole week's time and effort was spent searching an area 2500 miles from Perth, when a better analysis of the satellite communications data on Friday now suddenly puts the most likely site of the crash to be 700 miles closer to the coast.

There are only eight hourly points in a time series giving distance and speed away from the satellite. Given that the radar data in the early stages of the flight is - at best - of very modest use, why did it take a week to make the fix?

There are only so many possible speeds; follow a swarm of consistent Monte Carlo-ed paths to the best place to search, and don't be distracted by various random pictures of whitecaps taken by random satellites from random countries.

It would seem to be long past time to release the full set of distance and speed values from the Inmarsat system and allow the world's spring-breaking students to mail in a guess. They couldn't do much worse.

There's also the issue of the lack of information about the time of flight after 0811, other than to say that it didn't extend as far as 0911. It could be anywhere from ~100km to ~900km. None of the search box plots include this degree of uncertainty along the track. Is this reported partial call after 0811 being assumed to be a clear sign of the first engine running dry, or is it wanting to present an unduly optimistic picture to the press?

There is a pressing need to try to find the wreckage before the sonar pingers run out of power, but that goal is surely not served by doing lots of MPA flying in the wrong place.

Ah thanks. So the assumption that has changed is the amount of fuel left at the point of that last radar fix. From then to the last partial ping is a fixed time interval so you have to adjust the speed to get the right fuel efficiency for the remaining fuel to last that length of time. Then you can compute speed multiplied by time to get the distance.

I'm sure it's more complicated than that but is that roughly the idea ?

No, in less time.
He was out of fuel sooner. The last ping really doesn't define when exactly flight ended, we don't have this data, not yet.

New search area
 

Unless they are trying to obfuscate because they have data from another source they don't want to talk about.

olasek

No I get "energy" (work).
But to be fair, "time" is the only part of the equation we have (08.11).

Then again, that is an assumption !

What the Malaysian minister for chaos should have said is...
We believe the distance to be shorter AND THEREFORE he was flying faster.

What he said was "He was flying faster (an unknown) and so likely the distance is shorter"

so how much closer to finding MAH370 would they be if there were no pings, compare the area they could have had to search with no pings to the current general area, ( with the north now excluded|).

Pinger detection
 

Submarines listen to low audio frequencies, which can travel very long distances underwater.

The pinger is at a much higher audio frequency (37Khz) which is attenuated (reduced in strength as it travels) much more quickly. It might not even be detected from the surface in a deep ocean, much less at distances of many miles.

Also, as far as is publicly known, submarines are not equipped to even listen at the high audio frequency. Of course, actual sonar capabilities are highly classified.

FD Security
 

I posted this long ago.

There should preferably be a second FD access door to prevent follow-through.

I found a reference to IATA considering this but now I can only find this article on the proposal:

http://www.nytimes.com/2013/07/17/bu...-security.html )

There should also be a third person on the FD so that there can always be two on the FD at all times. This 3rd person could be security instead of FC if necessary.

Partial Ping and Fuel Starvation
 

I know we don't have anything concrete yet but I thought there was a relative, rough consensus that the partial ping occurred at the time of fuel exhaustion as what else but an engine shutting down could have triggered it?

The only thing that sort of explains the "flew faster in the same amount of time, ergo, flew a shorter distance," that I can think of at least, is that the westbound leg was flown faster than previously believed, leaving less fuel for the southbound leg, which meant the southbound leg would have had to have been flown at a lower thrust setting for the a/c to stay aloft until the partial ping.

???

What he said is correct, they FIRST computed he was flying faster (say based on radar returns, I don't think they explained how) therefore distance had to be shorter. You got it backwards.

I don't know about any consensus (I don't live on this forum) but such consensus would have absolutely no solid facts behind it, just guesswork.

It does if you look at the SLF as prospective terrorists. It might be wiser to look at them as the last line of security. Keep in mind that it wasn't the TSA gropers that stopped the shoe bomber - or the underwear bomber - it was the passengers. It was also the passengers who kept the 4th 9/11 plane from reaching its target.

Things changed on 9/11. Before that, hijacking pretty much meant sit down, shut up and go for a joyride to some third world country. Now, even the SLF realizes the rules have changed, and they are ultimately responsible for their own survival - and that of the people who know how to fly the plane. Pilots need to remember that the passengers aren't the enemy.

Guesswork
 

Fair and important point, it is complete guesswork.

I guess a better way to come at this is that I haven't seen any explanation for the partial ping other than that it was triggered by the engines shutting down. So if this whole "flew faster and not as far" business means authorities are recalculating the distance flown after the partial ping, then we don't seem to have even a theory as to what caused the partial ping (as it would not, it stands to reason, have been the engines shutting down). That is certainly possible. It is also weird.

Maybe others can shed some light on what could cause a partial ping?