Malaysian Airlines MH370 contact lost

[MG23]

Originally Posted by buttrick

It would be exactly the sort of consequence of the gennys going off-line and RAT or APU coming on line.

I believe the RAT won't power the SATCOM terminal, but the APU presumably would.

[FGD135]

Anyone see a problem with this geometrical method?

No problem, Mises, but there are an infinite number of solutions to it.

To buttrick and the others that are still having difficulties understanding how, if the plane was at a higher speed, the crash location would be closer to Malaysia:

If the plane travelled faster, then it would have achieved less range. This is a well known fact of aerodynamics. The laws governing this reality are the same as those for your car. Try driving somewhere at 100 until you run out of fuel. Then, try again at a speed of 80. You will get further along the road at 80.

So, at the higher speed, the plane covered less distance. Therefore, the crash point is closer to Malaysia than originally calculated. So the crash point would still be on the 40 degree arc, but at a point further up - which is a point to the northeast of the original area - which is exactly how they have moved the search area.

[porterhouse]

They have a duty to explain this conclusion in excruciating detail,

99.99% would not understand the explanation, and because of that would claim conspiracy, including the most 'vocal' victims.

but legally under agreements signed under the auspices of the ICAO

Under ICAO charter they have to eventually come up with the report, there is no duty to stand in front of some hysterical crowd
and play psychologist and mathematician at the same time.

[olasek]

Something is missing.

What is missing is that some people are married to the idea of time being known, constant, this is a mirage, at best we know elapsed time of this flight +/- 20 mins.

There is a PR machine at work, portraying the Chinese families as "hysterical"

I would claim reverse - there is a PR machine to give those few 'hystericals' more credence than they deserve and discounting families of other passengers.

[p.j.m]

Originally Posted by sflaperons

They have revised the TAS upward, keeping flight time constant, and yet somehow arrived a shorter distance traveled. That doesn't make sense.

Have they?

I think the only thing that has changed is where around the 40° arc they are searching.

Speculation about the speed the aircraft may have been traveling and when is just an irrelevant furphy (primary radar speculation withstanding) until the black boxes are found.

[500N]

Glen

Holding multiple press conferences makes you a target.

I think what Amsa are doing releasing multiple updates, charts and photos via the internet plus the raaf pilots bad pollies found media conferences has kept everyone in the loop, even when large changed occur.

Just my HO.

[mm43]

From the published chart the six "pings" before the 00:11 read on the chart at:
~18:25, ~18:28, 19:40, 20:40, 21:40 and 22:40. They are not every hour, as written everywhere:

In practical terms, I suspect that the 'pings' happened every 30 minutes, i.e. 11 and 41. My question would be, "Where are the missing 'pings'? Did they not fit the expected Doppler.

In relation to the 18:25 and 18:28 graphed points, there is no straight forward explanation, but may be the cockpit SatPhone has been used??

[buttrick]

You used the word "same". Such a word implies two things. Of what two things do you speak? Are you referring, in the case of MH370, to the following two enroute scenarios:


1. Cruise speed based on original assumptions, and
2. The higher cruise speed, giving rise to the search area being moved to the northeast

Same elapsed time - 6 hours from last radar return (if not bogus)

[LongTimeInCX]

But don't forget, you'd need a dog on the 4th seat just in case the retired Captain decides to go postal with the Taser.
I'm glad this thread has degenerated to a level whereby all commonsense, reason and useful facts are no longer being submitted.
I wonder why I stopped reading this a while back, and now I know.
When you have 'members' who are clearly not professional flight crew clogging up pages because they can't understand how you can travel less distance when cruising at a higher speed, you have to wonder.

Let's hope the ongoing search can reveal a few facts, then perhaps 99% of the posts by Mar2014 joiners can be eradicated to remove a lot of the uneducated bullcr@p.

I'll give this post 5 mins.

[FGD135]

Something is missing.

The most likely thing to be "missing" from their statement is a revised fuel quantity estimate at the start of the southward journey.


These guys are constantly revising their calculations and assumptions. You can't expect them to tell you everything all the time.

[JoeBloggs2]

The assumptions are to cover the move of the search area 1100km NE

I am also willing to assume based on the rest of the pings that the aircraft flew a 'track' of some kind not just circling west of Sumatera...

But agreed not enough real info

[RatherBeFlying]

In the hope of reducing the quantity of posts here on range and speed, it may be helpful to summarise from D. P. Davies Flying the Big Jets as best my fading memory permits:

1. Fuel consumption in a jet at cruise does not much change with altitude
2. True Airspeed is substantially greater at cruise altitudes than lower down
3. i.e. at cruise altitudes you get substantially more nautical miles per pound of fuel

The alleged low level sector to past Banda Aceh used substantially more fuel than if it had been done at FL350, leaving less fuel for the Southbound leg.

Obviously somebody has worked through the performance charts (or plugged the numbers into the computer program) to derive a new expected range from the last suspected turnpoint and has plotted that to the final ping arc -- and has incorporated the uncertainties to produce a search area.

[porterhouse]

total flight time has apparently stayed constant throughout this revelation.

Only through misinformation spread in this forum.
I don't recall any press briefing where someone would claim a certain known 'constant' elapsed time of this flight.

[Shadoko]

Simple physics:

Nobody knows if the place where MH370 gone in water was at fuel exhaustion.

If they supposed the flight was slower (for any reason), they have to make its trajectory more east:
1- To have the frequency drift (from Doppler effect) to remain the same*: it is because the drift is related to the speed of the a/c relatively to the Inmarsat sat. At 0:11 (UTC) the sat is wobbling to the south, so its speed has to be substract in whole from the a/c speed if the a/c is also going south. If the a/c goes more east with a lower speed, the result of the substraction remain the same, because the sat speed you have to substract is smaller.
2- The time between the path comes into two successive "arcs" (from pings, not published) have to be smaller, so the path have to be "more perpendicular" (to the "arcs").

*More west (mirror path relative to North-South) would have the same effect for the drift, but the "40° arc" at 0:11 could not been achieved).

[Ornis]

Confusion

For any given time interval, a higher average speed means the distance travelled is more.

For any given fuel load, a higher average speed means the distance travelled is less.

Both statements are correct.

[Stanley11]

I'm going to sound heartless but would like to state a fact here. From this event, we can see how disproportionate air disasters are treated as compared with other accidents. It is unfortunate that 239 lives were lost in one event but more lives are lost on the roads everyday. The amount of money poured into this incident is astronomical. Frankly speaking, considering how rare this incident is proves that there already are sufficient layers in the aircraft and off-aircraft systems to 'prevent' something closely similar. The reality of it all is that we may not see any changes made after this incident. The cost versus probability just does not work out. It is like the 50-year storm or 100 year earthquake. Do we see huge tsunami walls built along the west coast of thailand? So I wouldn't expect much to change that will result in expensive hardware upgrades or mods. Perhaps only policy reviews and tighten procedures, if ever they find out the loopholes that led to this incident.

[Shadoko]

mm43: In practical terms, I suspect that the 'pings' happened every 30 minutes, i.e. 11 and 41.

The published chart (http://www.straitstimes.com/sites/st...325/graphe.jpg) is a little misleading in the way that the dots "measured" are joined: OK for the South and North "predicted tracks", but joining the dots of the pings truly received is going too far (IMHO): anything could have happened between them!

[Ixixly]

You're going to sound ignorant Stanley11, you cannot simply say that because it has never happened before, this is the first time something like this has happened then it's obviously a once off so why waste all the money? What happens if something like this happens again? Will you explain to the families and friends of the next 239 people why they're lives were not saving because of an assumption?

There is still a good chance this aircraft will be found, there are solid leads and items that can potentially be recovered that have been identified, they will not give up until they are positive there is almost no chance of finding it. The Inmarsat details have given them a credible lead, satellite images have found possible debris in the area they suspect it went down in and there are still a few days left for them to try and hear the pinger before it's battery runs out. So why would they discontinue at this point?

You're right, people die on the roads all the time and you know what? MASSIVE money is spent on preventing that, by thousands of authorities around the world, by all the major manufacturers, but hey, there are millions of vehicles out there driving all the time, billions of kms a year that they drive and only a very small portion of accidents so why bother with that either? Probabilities show it as having being infinitesimally small chances of it occurring...

[Mises]

For the sake of clarity, my understanding is that the last ping responded to was at 8.11. Another ping at 8.28 went unanswered. If that is correct and confirmed, the flight time is known to within 17 minutes (approx 130nm of flying).

Can someone confirm if this timeline is official / confirmed?

[Mesoman]

Probabilities

It's important not to look at unconditional probabilities.

For example, it is highly unlikely that a specific flight will end up the way MH370 did. And yet, MH370 had the extremely unlikely result.

If we say that it's highly unlikely that cause X could happen, that doesn't help. What's important is how likely is cause X compared to cause Y, under the condition that the MH370 event actually happened.

Thus cause X can have a very small probability. But given that this event happened, the probability in this event is obviously much higher. If we summed up all of the unlikely causes, the result would be 1 (100%). The important probability is whether X caused this accident, out of the set of all possible causes. So, 10 scenarios (for example), each with an unconditional probability of less than 1/1,000,000 add up to 100% when you take this into account, because under this condition, they would average 10% (1/10) rather than 1/1,000,000.

The key here is to look at the relative probabilities: rank cause X and cause Y etc and compare them only with each other.

SAR officials understand this. Conditional probabilities of this sort (and with lots of other things thrown in) are fundamental to assigning SAR assets - picking what grids to search and when and how and how often to search them, adjusting as the conditional probabilities change in response to the results of negative findings.