jcjeant

Prosecution is unlikely. Generally, the authority pleads ignorance or stupidity, (or allows it to be unchallenged). There are too many patent defenses launched by "Government" or its "Agencies" to allow for justice, just sayin'.

There is an opportunity here in Private Enterprise that will out, and as soon as people realize that 447's resting place is in the public domain.

bear

Bearfoil
Once again I find myself having to remind you that searching the sea bottom without knowing where the objective of your search is, is a very difficult task especially given the configuration of the sea bottom in that area. It is possible that the wreckage may never be found but you can rest assured that BEA will have done what they could. Their knowledge about where to search is also likely superior to yours and they are not going to try and avoid finding the wreckage. The deep sea environment is a totally alien environment about which very little is known and all comments on the search should bear this in mind.
Old Carthusian

Old Carthusian

Thank you, Sir, I stand reminded. I am also reminded of thousands of posts that include some critical of BEA in addition to mine. I mean not to present unattainable expectations, only that to stop now means neglecting part of a likely area to search. I also have a persistent feeling that BEA have "Phoned it In". Hope not, but why so long?

I know not why you feel the need to defend the investigators relative to the getting wet part, when deeper searches have proven successful; I think others could do better, faster, and for less money. I think a commercial venture would be excellent, there would be no doubt whatever their motive to find, simply find. Of course it is a daunting task, I wrack my little brain trying to remember where I said it was not.

I think you think I think not so.

bear

Bearfoil

Thank you for your reply - there are indeed grounds for people to query BEA but this area is not one of them. You refer to the depth of search but this isn't really a factor. There have been examples of unsuccessful searches in shallower environments than this. The configuration of the seabed in this part of the ocean is the issue. It is extremely rugged and varies quite significantly in depth. This creates very great difficulties in locating and identifying wreckage. I, myself, have no real surprise that it is taking so long the cliche 'needle in a haystack' comes to mind and no doubt others have used this before. The other searches you refer to have been conducted in relatively flat and easier conditions. However, I can assure you that BEA is not satisfied with the results of the search so far - it has cost them a lot of money with nothing to show for it. Your posts seem to indicate that you believe that they would rather the wreckage was not found for whatever reason. This is an unlikely situation - for various reasons the aircraft needs to be cleared of blame or the correct remedy to this set of circumstances needs to be found.

Old Carthusian

To Search or Not to Search?!
 

I for one, have supported the efforts of the BEA, even through the difficult areas of interpretation caused by language. I still am of the opinion that even though their efforts to locate a debris field have so far been in vain, it has not been achieved without a good deal of consultation with and effort by those well versed in the environment the aircraft is believed to have sunk in.

With that in mind, and with some other knowledge that I have about on-going research, I venture that it is rather premature at this juncture to write off a further search not eventuating.

As I mentioned many posts ago, enjoy your Xmas and be reinvigorated for more delving in the depths of the Equatorial North Atlantic in the New Year.

mm43

Has anybody else noticed that....
 

...this thread is starting to sound like the websites of the people who steadfastly remain convinced that 9/11 was an inside job and the towers were brought down by dynamite in the face of engineering analysis?

Hi,

I think this message has no reason to be there because:
The comparison is very badly chosen
It does nothing about the subject here
It would demonstrate that people who post messages here are adherents of conspiracy theories ... and that is not true
Anyway everyone is free to have views but it seems to me that this message is a sneaky approach to make close the post ... and so don't reflect any views or a argumentation about the subject here.

jcjeant;

I think JD-EE's post was meant more as a tongue in cheek "observation" than as an argument or alternative point of view.:)

mm43

jcjeant...

I think JD-EE's comments refer to some posters who have been suggesting that BEA does not want to find the remains of AF447. If that were the case it would suggest a conspiracy within BEA. No matter what pressures are exerted on BEA (and there are many), and what mistakes they may have made early on, I don't believe it's correct, or helpful, to suggest ulterior motives to the agency.

On your other point, I would be very surprised, based on previous posts, if JD-EE's intent was to shut down this thread.

But I could be wrong. Perhaps there's a conspricacy to... Oh never mind.

Sam, I'm trying to start a conspiracy to get this thread back on track and off directions that, in today's world, are simply unrealistic. If one credits BEA with the brains to solve this if they want one cannot simultaneously ascribe to BEA a conspiracy to hide the truth.

Those who finance BEA do not give BEA bottomless pocketbooks for this investigation. Taken to the absurd an infinitely funded BEA could survey every bit of ocean in the world before finally surveying what everybody thinks might be the final resting place of the plane. They'd survey it so that the rest of the world would learn more of what IS down there or some such motivation.

More realistically they have to convince the holders of the purse strings that any money granted the BEA will be spent wisely AND that the results are likely to prove fruitful.

In the final analysis the "target" is a very small pair of needles in a very large haystack, the FDR and the CVR. I don't think one without the other will prove conclusive. I'm not sure both together is going to settle all or even enough arguments. (People will still rely on stupid slogans like "Steel doesn't melt at XXX degrees" while ignoring details like most of the strength of steel is lost at temperatures considerably below melting temperature.) How much more money are the holders of the purse strings going to be willing to spend?

Consider some of the problems. We do not have a good estimate of currents below the surface in that area at that time. We do have some notion now that people have been down in the ocean observing the currents as a side effect of taking a good look around. We don't know that the CVR and FDR are still attached to a large enough chunk of plane to be found. If they are not and hit on a slope they MAY be underneath an avalanche where sonar alone won't find them. They'd have to find all likely avalanches and send something down there to excavate or use some means of exploration that would reveal the boxes.

Yes, I do think they should go down in the slightly less likely areas. It appears they presumed the plane remained largely on course with a deviation around the storm to the North, perhaps North West. Now they need to presume forward motion stopped much sooner, as early as the last position report, and the plane may have flown "considerably" off course trying to recover from its upset.

Meanwhile, somebody should be contracted to see how pieces of an A330 airframe, particularly pieces around the recorders, would sink. What is the density of the composites compared to equally strong metal parts? Somebody else should be contracted to use some new imagination to "guess" what upsets might be involved. The failure analysis tree is very large. And it may be that in pruning branches that look unrealistic the cause might be missed. Some pruning comes even before the tree is built because of prejudices, "XYZ simply cannot happen." A silly example is "God reached down and swatted the plane out of the air." What less silly examples were left off their trees? A fresh look might be productive, if egos could stand it.

But one failure I am not willing to presume at this point is a conspiracy to withhold and bury evidence. "Wikileaks" still exists. They simply cannot afford to do it. The downside is too great AND the probability of a leak in today's climate is close to unity. And THAT is the chief equation I am drawing to the 911 Truthers. In either case suggesting conspiracy is rapidly becoming as boring as it is silly and unproductive.

JD-EE...

Well said

:D

Pattern
 

In the sequence of ACARS messages are a number of 'silences'. A silence means either that there is no message to transmit, or that the satcomm link is lost. I've been intrigued by an apparent pattern in these silences, which is shown in this graph.
The red bars mark the gaps in transmission. They are initially spaced at 27 seconds, and 30 seconds after 02:12z. Any significance in this?

regards,
HN39

EDIT:: Examination of the message timings shows the following:

2:11:00 +15s - Four WRN messages time-stamped 2:10 waiting. Therefore lack of messages was not the reason for this gap.

2:11:27 +15s - One WRN message time-stamped 2:10 waiting. Therefore lack of messages was not the reason for this gap.

2:11:55 +15s - Two WRN messages time-stamped 2:11 waiting to be transmitted before 2:12. Therefore lack of messages was not the reason for the silence until 2:12:10.

2:12:16 +35s - There may have been messages to transmit but that cannot be concluded from the timings.

2:12:51 +17s - Two FLR messages time-stamped 2:11 waiting to be transmitted before 2:13, therefore no reason for silence until 2:13:08.

2:13:14 +31s - There may have been messages to transmit but that cannot be concluded from the timings.

2:13:51 +23s - There may have been messages to transmit but that cannot be concluded from the timings.

If 447 had "stabilized" in a descent of say 5-7k fpm, there is room for an established Phugoid while descending to blank the signal in an apparent "Period". Likwise, if the aircraft had become "stable" (unacceptably) in a rotation with nose down, the airframe may have occupied an aspect that similarly blanked ACARS, seemingly in a "rhythm".

Edit, Since JD-EE has said that a signal may take 30 seconds to re-establish, we may also be looking at an interruption that is immediate, and a re-acquisition on the order of the 27-30 seconds?

This is an enormous airplane, and local velocities are distorted towards the "gentle" when we visualize. Every thing this airplane does is "slow", but occasionally only in scale.IMO

JD-EE

With great respect, onlookers have busted the King's nakedness for centuries. Somewhere between your naivete and my aggression towards BEA, is the balance that people seek who wish not to believe that which is to them impossible. We live in a World where information that is readily available is ignored, or where no data at all is used as "evidence", on this you are quite correct. If you are unwilling to entertain less than noble motives on the part of BEA, that is your prerogative.

Others may wish to ponder to what extent incestuous "Guardians" may go to protect a Trillion Dollar Enterprise. To each his own, if you are offended, look away.

What Is somewhat disturbing is your dismissiveness and arrogance. I take your point in general, but frankly, some of your rhetoric is beyond dismissive, as it seems to pander to those whose views are similar, but in an adversarial way. Pity.

Much respect to you,

bear

I don't think that I buy into any conspiracy theory, but more one of actions. My concern over BEA’s procedures reverts back to when the accident occurred. Whenever an airplane goes down in the ocean, the first few days of search and rescue are critical. Each day afterward increases the difficulty exponentially as the footprint of sunken debris can shift, deteriorate, move around, and become covered. It is therefore paramount that all possible effort and resource be devoted immediately to the task of locating the site. Underwater detection capabilities is best achieved by the military, yet no request to Governments which obviously have this capability was made. The British claim that their subs while sitting in the UK have equipment that can detect a ship that is leaving New York harbor. To me it appears that the BEA took more of an attitude of job ownership (and pride), rather than at best humbly request outside resources which could have been made available. The precious time to find the airplane lingered, on and on and on. I fear there is every likelihood the site will never be located, not after such a long period. I hope that I am wrong.

wes wall

The word itself, conspiracy, has acquired an odious and paranoid feel. It is the most marginalized of words, and panders to the wide scope of ignorance in the Field. It merely means an agreement between (among) people to do mischief. A practical joke is a conspiracy of sorts. An Industrial or Administrative entity, in pursuing its mission, daily engages in conspiracy. If one hasn't the objectivity to grasp that, and instead goes to the fear of fear, (paranoia) directly, one should consider eliminating the word from one's working (?) vocabulary. Eh, my friend?

bear

bearfoil, I am mainly suggesting that it is premature to buy into a conspiracy of silence. The downside is too great given the probability of exposure. There may come a time when it's proper to consider such things. Let's first dismiss most other probabilities.

One interesting thought was fed to me in a convention session this past week. Different cultures think differently and have different "blinders" on. I remember reading of some relatively recent research that indicates some of this is "language" blinders. For example, with most European languages you're forced to convey a sense of "sex" with each object you describe. The article showed how this appeared to affect architecture. They drew a comparison between the gender of the word "bridge" and the form of bridge commonly built by the culture. This effect could affect the BEA experts to dismiss some things that should not be dismissed. Can we dismiss that potential before we jump in to indict BEA for conspiracy?

(It MAY be time for BEA to listen to talented outsiders to give them more (idiotic as well as good) ideas to dismiss in their searches for clues and causes.)

Conspiracy is a very serious charge (at least in North America for the most part.) As such the charge of conspiracy must be associated with strong evidence rather than mere "it looks like" and (as with 911 Truthers) faulty "common sense physics" which more resembles "cartoon physics." You're welcome to the BEA conspiracy theory. Just please be prepared to be vigorously challenged to prove it if anyone cares to push it very much.

In the total time I've been reading these threads conspiracy by BEA to withhold evidence and not find other evidence has been brought forward many times - never with a nice clear solid argument in support of the accusations. Please bring evidence of a smoking gun.

{^_^}

HazelNuts39, I was about to shake my head "Yeah" to bearfoil's phugoid scenario when something dribbled into my thick skull regarding the timing of the transmissions. I don't know (or have forgotten) how long each ACARS message plus handshake takes AND what length of guard time must exist between messages. I also don't remember if BEA established AND published whether there had been any other transmissions that would have consumed some of the blank intervals.

Messages appear to take (an incredibly long) 6.5 seconds. There were just a whole lot of planes in the air that would be using that same satellite. Message frequency is normally very low. What is the usage rate of that particular satellite channel? Could some of those time intervals been consumed by other competing messages?

That aside some form of attitude instability would make sense with a periodic transmission interruption. However, the number of interruptions you have charted seems high to me.

I also believe that BEA did not comment about messages being delayed from the time it was expected the message would be sent other than the messages that should have been cued for transmission next after the last message ever transmitted.

That basically says, "This is an area that could be reviewed again." Once we know the duration of typical ACARS message transactions that can be added to your charts to show gaps that are suspicious. Then we'd need to ask if the message after a gap would have logically been sent earlier if it could be sent.Let's establish the phugoid spin as being near the same level of probability as other possible explanations.

I've long entertained a attitudinal upset or spin scenario to explain the gaps. Maybe it's time to establish how likely messages really WERE delayed. I've probably been remiss there.

{^_^}

JD-EE

As you say, conspiracy is a serious charge. I have never made it, relative to any part of this accident. Long ago I defined what I thought was afoot as a certain lack of interest, or momentum, if you will. The Inertia of a large group can be hobbling in ways that mimic actual wrongdoing. Many times here, the language bug has appeared. I can't prevent others from calling what I write a "conspiracy theory". As above, the word itself has lost virtually all its meaning in modern discourse. It is almost exclusively used to savage an opponent as "Irrelevant", an "idiot", or other. What is most discouraging is the lack of agreement about the word itself. This has polarized people into two groups, each permissive of nothing that isn't in complete agreement with either "Party Line". It is intolerant of criticism, or disagreement, and stifles objective debate. All I have tried to convey is BEA's at times "laziness", a lack of assertiveness and a reporting system that is wide open to proofs of same. This does not even include their distressing lack of clarity and transparency, something that insults almost everyone who has an interest in this accident.

It is extremely difficult to prove foul play, and I doubt there is any to pursue, can I make it more clear? In the absence of anything done, it is difficult to demonstrate a motive of any kind, and why would anyone attempt to do that? Hard to make a mistake without doing anything.

I'd like BEA to get off the damn dime, or failing that, explain what is happening, from their point of view, Fair?

edit: JD-EE, I haven't considered Phugoid and Spin together, and am not sure it is even possible. A phugoid would have to be consonant, not increasing, decreasing, or "interrupted" to add some cycle that is consistent with HN's graph, this in itself may not be likely. A flat spin may be more likely; loss of signal with one aspect (orientation) followed be a re-acquisition of signal, followed by the same aspect with another signal break. I can't get any further with it than that, so HN's graph is most intriguing, and should be addressed by someone who has the signal skills with an experience of heavy/unusual attitudes.

bear

bearfoil, why are you taking it so seriously. I did not comment to anybody in particular. I'd simply noticed a trend in the discussion which is fatal to considered discussion, as fatal as breaking Godwin's law.

One would think that you thought it applied to you. I note that I am willing to let anybody try the shoe on for fit. It's not a shoe *I* would want to wear.

{^_-}

The "Why"
 

According to the time stamps in HazelNuts39's excellent graph, all hell broke loose prior to and during the minute of 02:10, with fifteen messages time stamped during those 60 seconds. By message 16, beginning with time stamp 02:11, the situation had likely degraded to irrecoverable, and by time stamp 02:14 SATCOM sent the grim hint of an aircraft falling from the sky ("Cabin Vertical Speed").

JD-EE's failure analysis trees might be characterized as "event trees," and they are, indeed, complicated and many because the data are simply too sparse to easily "hone in" on the event. Start with AUTO FLT AP OFF and work backwards... What would cause this message? Unusual attitudes? Failure of GEN1 and transient electrical disturbance? Tie in a branch for PROBE-PITOT disagreement causing out-of-parameter airspeed calcs. Tie in a branch for overwhelming meteorology. A branch for radar (failure). etc. etc. Such an event tree is , as JD-EE stated, "very large," but when properly weighted, this upside-down tree might point to the WHY in a best-guess methodology.

An understanding of the A/C's attitude during its fall might help to narrow the search area beneath the 02:10 LKP, a good effort by HazelNuts39. But it seems to me that any answer as to WHY the upset occurred that can be derived from the ACARS messages lies in the group of messages time stamped 02:10. The rest were sent as the plane went down, and again, they don't tell us WHY it went down...

A readable CVR and FDR would "rule in" conclusions in the event tree(s) about why the aircraft was upset. Analysis of a recovered hull and debris might "rule out" other conclusions. Pardon the double negative, but I cannot imagine how BEA could refuse to continue the search! As mm43 counsels, stay tuned for a new phase in the new year.

GB

What is the 911 official story if not a conspiracy ?
Where is the strong evidence that OBL did it ?

Please, let’s stick to AF447 on this interesting thread.

Absolutely in agreement, but if we wait too long, corrosion may destroy the data.
Also, kudos to HN39 for his ACARS message timing analysis.

I've stated it before, but I'll repeat again. BEA & Airbus would have serious credibility problems if they gave up on AF447 and we then had another similar accident. These searches are expensive-but in the big scheme of things, not that expensive. Should BEA give up the search, that would allow any 3rd party to conduct a search of their own, which would be embarassing, particularly if successful.
If we ever find the cause of AF447, I personally believe it will tie in to the protections built into the flight controls. Sorry Airbus, but leaving the aircrew no way to override protections except by a cumbersome degrade procedure was not smart. When the Fit hits the Shan, seconds count. The recent Perpignan accident report shows how dangerous an Airbus can be when presented with erroneous flight data of the type resulting from a common mode failure.

For those who feel the need to keep this thread visible by proposing continuing conspiracy theories, I wish you would stop. I think what you end up doing is trivializing this thread in most peoples minds. Lets try to only post news and new theories/questions and keep the thread on track.

RE: Loss of SATCOM. Question to our comm specialists: Does this mean that for loss of signal the airplane must be banked 67 degrees away from the satellite (assuming satellite position was 28 deg from vertical for the AC position)?

CMA-2102 Data Sheet

Jane's Avionicsregards,
HN39

I guess I have a question about the Beam steering unit. Does it rely on data from the aircraft's system for orientation, or does it use satellite signal for orientation? Probably a related question is whether the antenna has sufficient gain to communicate by way of sidelobes as well as the main lobe? (I.E. can it lose lock and still communicate to some limited extent.) Not really more than a baseline description in those documents.

HN39, the analysis is not quite so easy as to admit a precise angle.

If I presume there is no navigational feedback to the antenna aiming algorithms a gentle roll that leaves the antenna no more than (conservative bogey number) tilted less than about 75 degrees will be tracked and communications can transpire. A rapid roll would destroy antenna lock once the antenna fell out of the beam - say 40 to 50 degrees of roll even if the beam could be steered to point to the satellite. If there is navigational feedback then you're back to the the detail that the antenna cannot effectively steer to smaller angles to its plane than 15 degrees or so. (Somebody familiar with polar routes may correct me on precisely what latitude is the limit for SatCom capability on aircraft. My experience is with land/maritime SatCom and I know that works adequately down at angles around 10-15 degrees. That's with physically steerable antennas, though.)

I believe navigational aiding exists for the antenna. So I suspect that a rather dramatic event would be required to shadow the satellite. My memory insists the pertinent satellite was somewhere "roughly" near the African coastline. So I'd expect such an unfortunate event to be a roll with left wing down in this case, perhaps after the plane was oriented well off course to the North. ("Oh Shirt! What's that!" as the pilot pushes stick forward and to the left to avoid that suddenly appearing bright light ahead of the plane getting larger fast. (Grumble) We cannot even rule out a UFO sighting and a move to avoid striking it. Ball lightning does freaky things.)

I didn't answer your comment with a number. But I hope the data above helps visualize what it would likely take.

Machinbird....
The downside to a conspiracy for BEA is high with regards to exposure and loss of faith in France, French airlines, and French airframes. That's so high a risk it's hard to envision them taking it.

I can envision then "cheaping out". One airframe saved is XXX megabucks. That loss has some small probability per year. (Decades before one plane went down in these circumstances?) What's the cost in airframes per year for continued search? The risk of "cheaping out" is much the same as above, though. So they are under immense pressure from two sides to not only solve it but to solve it cheaply. I can understand there being considerable deliberation before spending more money in bulk measure.

Regarding nav aid - I am SURE the antenna can self track the satellite. The marine antennas I worked on tracked fairly easily. Once I rewrote the algorithm I had a lab unit tracking within 0.1dB (about 3%) of the peak signal. I described a square in the sky. I moved it until the signal level from all four corners was equal. I then knew the antenna was pointed very near the satellite at any given time Precise pointing was worth that fraction of a decibel in signal level. The antenna itself had accelerometers that allowed it to track in remarkably rough sea states.

For the airborne antenna the antenna gain is less meaning it has a wider beamwidth. In fact it is so wide that a simple navigation feed from the plane can keep the antenna aimed properly. Attitude feedback can ensure lock even if the plane is tilted. I'd expect that. I can't guarantee that it is there. Again, it's such a simple thing to add that correction to the antenna aim that the thought of not doing it feels "dirty" to me. If it comes rapidly enough, say once every 10 seconds or less, it'd take a REALLY violent move on the part of the plane to make communications impossible.

Hi,

Cost of a new A330-200F: $194.8 million (official price)
Cost of researches so far (as know by the press) : $28 million

JD-EE;

Thanks for your detailed reply. As to the satellite location, BEA has established that the ACARS messages all passed through Inmarsat Atlantic Ocean West (AOR-W) which is at 53 or 54 degrees West (sources differ), and would put it West of the aircraft at an elevation of about 72 degrees.

regards,
HN39

JD-EE
Good morning. Your explanation with visual was excellent. Given HN's stated SAT position, I figure a roll either way gains the a/c access with the Satellite via its dorsal antennae placement.

What would not be conducive to signal maintenance would be (imo) a Pitch Down.

Roll limit in autoflight before involuntary uncouple is 45 degrees. The Pitch Down limit is 15 degrees (9 in PU). With a signal at ~70 to horizon and perhaps 8 o'clock (?), some combination of Roll right and nose down would cut the signal? The cycling in HN"s graph suggests exactly what, to you? In either extreme of attitude, whether only PD or Rolling with reversals, what would the related aerodynamic picture of this signal behaviour be in your opinion?

bear

bearfoil, "Deponent sayeth naught."

(Meaning I am a EE not a pilot. You guys are the experts on how planes can misbehave in the air.)

I will note that we've not established the minimum "allowed/possible" time between ACARS messages. For that I'd need a copy of the Inmarsat specifications for that mode. I suspect the channel is very low data rate and there may be a hold-off interval. That hold-off interval MAY vary with "history". Until we know these details I'm not sure we can find most of the gaps HN39 found. The two really long ones need explanation. The others may be artifacts, especially if a message had to be resent for whatever reason. (I can almost see a potential for such congestion if we consider all planes that might be in AOR-W's footprint and the toilet configuration errors from AF-447 suggesting some small level of traffic is normal.)

This is one area BEA needs to explain a little more, IMAO. Can they explain the precise timing or is there something to those two long gaps. (And as I wrote this I had a "duh" moment. Yes, there IS a minimum interval between messages. During that interval data is coalesced into more compact messages than if they were sent one at a time. So an extra few seconds could very well be a transmission that needed to be sent a second time.

ACARS Sequencing
 

HN39 has raised an interesting point regarding the sequencing and 'dead' time slots in the time apparently available, i.e. up to the handshake received back on the aircraft following the last message.

As a short refresher, here are the ACARS messages as time-stamped to the nearest minute, along with their receipt times:-

http://i52.tinypic.com/24culnq.jpg

An interactive web page with the above list is available from here. You can highlight one or more lines by clicking on them, and clicking again will return the line to normal.

Below is a revamped version of how the BEA described what was displayed in the cockpit, and what wasn't.

http://i53.tinypic.com/1zbxshl.jpg

Notes:

• The ACARS time stamp has been given a different background color for each minute.
• Warning messages take precedence over Fault Reports, and the 0210 position report had overall precedence in the ACARS sequence.
• Sequencing within the FMS of the AOC messages is not precisely known.
• The receipt timing (not provided by the BEA) of the 0200 position report in the ACARS system will provide a good indication of when the 0210 report was probably ready in the FMS to be inserted into the AOC sequence.
• Highlighted cockpit effect messages are secondary faults, i.e. not causative.
• The note associated with TCAS cockpit effect message has been inserted by me (from BEA Interim Report No.2).

The gaps in the message sequencing are for either of the following reasons, i.e.

1. there was no AOC traffic queued in the FMS,
2. data corruption required a retransmit,
3. loss of data link.

Total time for each message was approximately 6 seconds, which comprised synchronization, message header, data and receipt confirmation.

Finally, for those that remember the old Telex/Teleprinter systems, the ACARS protocol was a product of that time, and the data transmission speeds are similar.

mm43

mm43;

For the record: When comparing time-stamp to time-received, I have assumed time stamp is minute without seconds, i.e. 2:10 covers everything between 2:10:00 and 2:10:59, rather than 'rounded to' nearest minute.

JD-EE;
About 'gentle' and 'rapid' roll and pitch rates:

Roll axis: Regulation requires a minimum roll rate capability of 5 deg/sec at speeds above Mmo for recovery from lateral upsets. I believe the roll rates typically used when initiating routine heading changes are of similar order of magnitude. In the accident near Perpignan the A320 exhibited uncontrolled roll rates in stalls of 30 to 40 deg/sec.

Pitch axis: Typical pitch rate during takeoff rotation is 3 deg/s, in cruise probably somewhat less, say 2 - 2.5 deg/s. In the QF72 accident the airplane involuntarily pitched down at 8.5 deg/s, then pitched up in response to the pilot's control input at 5.6 deg/s.

regards,
HN39

HN39

I've taken everything at face value, and each time-stamped minute represents 30.1~60 secs and 00.1~30 secs, which is as you mentioned the "rounded" time.

As I mentioned in the earlier post, it would be interesting to know the actual timing of the 0200z AOC position report. It could conceivably help determine more closely when the 0210 time-stamped events possibly commenced.

Regarding the pitch and roll periods, the electronically phased array antenna is quite capable of tracking the satellite (provided it can see it) at far greater angular speeds than that recorded in the QF72 incident. Think of ships at sea; they often pitch and roll at remarkably high rates and even physically steered antennas manage to keep "locked on".

mm43

mm43;

I agree that whether or not the time-stamps are rounded is just one of many things we don't know. Note that the BEA doesn't speak of 'nearest minute':
.

regards,
HN39

mm43 wrote
I hope you are speaking about 6 seconds between each message
(anothers planes have had to transmit own messages).

If not, It seems difficult for me to understand a so long period to transmit a few bytes, even if each "transmission packet" needs an ACKnowledge signal before transmiting the folowing.

Even if ACARS transmiting rules are comming from RTTY, I don't think a message transmission burst needing more than a quarter of second.

HN39

"... to the nearest minute", doesn't provide an exact meaning, and rightly or wrongly I construed that to mean "rounded". The alternative would be to say the events occurred within the minute in which they are time-stamped.

Lets face it, the plus or minus 30 secs difference represents less than 4NM, and we haven't located (so far) any bottom debris within a 40NM radius of the LKP!

rgds mm43

First, mm43: Thanks so much for your great work (as usual)! Those depictions make it so much easier to get one's head around the messages and timings.

Speaking of locating the remains of the aircraft...

As it may relate to AF447, I have been trying to get a handle (as a lay person) on sonar systems, technology and capabilities. From my reading it seems the capability (and possibly the in situ equipment) exists to have recorded the noises of AF447's initial impact, descent of pieces, and even the impact with the ocean floor of some portions.

Apparently there may well have been stationary (permanently installed) sensors in various parts of the Atlantic, as well as onboard sensors of ships / subs at sea of course, that would have recorded the above mentioned noise.

We know the time (within a few minutes), so if there were even two or three widely separated monitoring / recording stations, then it follows that it should be relatively easy to arrive at a fairly precise location. This of course is predicated on the respective governments / agencies sharing data with BEA.

Discussion?

Sam

NeoFit;

The timing sequence is carefully described by the BEA in its Interim Report #1.

Possibly a gap or two was caused by the system reverting to its prime task of trying to do an auto-connect with Dakar Oceanic using ADS-C. I'm sure that the Dakar log would have recorded another "failed connect" if that had occurred.

The BEA in its reports has made no mention of satellite traffic queuing, so that can probably be discounted.

You are right about the speed! RTTY, Morse code and then semaphore comes to mind!

mm43

Mayday or not
 

There has been some arguments posted here about why the pilots of AF447 would not send any mayday when in beginning trouble.
On a.net you can find a description of an event on AF445 between Paris and Rio, where the pilot called mayday upon hitting severe turbulence.

AF445: Mayday Call Due To Severe Turbulence — Civil Aviation Forum | !!!!!!!!!!!!!!

The handling of CVR and other info by AF after the flight sound strange or sloppy to me. Furhermore, the disk problem with the QAR is also strange. Such things can often be solved (at least partly) by disk-specialists if one is willing to pay.
Nor do we know if any ACARS similar to AF447 were sent.
BEA is very silent about this incident and I had to dig around a lot to find a short comment saying that the incident was being investigated because it might help to shed some light on AF447.
Regards

AF445 -No ACARS
 

AF 445 GIG-CDG hit some severe turbulence, the crew was unable to obtain descent clearance and applied oceanic procedures by transmissting MAYDAY to perform a level change.
Clearance to a new level was later granted by ATC.
There were no ACARS messages.

As to AF447 not sending a MAYDAY, just think how the events might have unfolded.
Pilots are in their seats in cruise, they may not be wearing their headset.
All the alarms go off and one is handflying in turbulence during the night with limited informations, as they both try to solve their problem.
To make a transmission, one has either to put on the headset and use it's mike or to use the handmike wich is hanging on its hook under the side window , that's if it's still there in the turbulence or upset.