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Old 7th Jun 2009, 15:29
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ACARS via L-band, possible to RX for amatuers ?

First thread and not pilot, hope this is ok anyway with you all.

Could someone in pilot or eng-profession give a hint if my speculation in the following matter is of the wall or maybe possible in this tragic event?.

ACARS txm:s is via VHF ground network or switched to L-band via Satcom. Therefore it is normal that amatuers don´t pick up any of the txm:s on L-band. If the downed 330 had an array-mounted antenna for L-band txm:s and was doing a violent out of control flight, mother in Paris (receiving dish) should have a threshold point on rx, and as the flight may have been doing a lot of txm:s, it would be possible that more txm:s was aired but not recived by "mother" due to the gain-step setting (eB/no) in the receiver in Paris if the array-antenna was out of it´s prime focus during the last minutes.

As there are a minor group of dx:ers active on the L-band (microwave band), it could have been possible that additional data could have been recieved and stored on a hard drive at a l-band fan amatuer, as amatuers always are on the edge of possible receiving limits-settings. The only issue is if ACARS is encryped and how hard encrypted any ACARS-txm:s would be to decode.

Is there a back-up recordings at Satcom NOC downlink-station, or is Paris the only active downlinker for AF ACARS txm:s. It could maybe be a good idea to spread the world to the L-band people and ask if someone was recording Satcom ACARS on june 1st on 1700 band, especially if worst scenario occurs were´s the "blaxboxes" never gets retrived or are in a degraded condition.

Just a thought in this tragic situation.

Thomas in Stockholm / engineer.

Edit-1: Not sure if this link is the right antenna-config, but phase-arrays can be tilted a lot and mantaine communication, suspect more that the CB:s would damp the signal to a critical threshold depending on downlink size of dish and eb/no-setting.
Link is:

Edit-2: Also in mind, these array-antennas has a specific radiaton pattern, and when accessing satellites, usually the NOC keeps an record on time-signalstrength etc for tech-monitoring and billing purposes. So with the NOC data and the previous post of the ASCARS messages, it could may be possible to determind the angle of the A/C if a calculation was made of NOC telemetri-data compared with the time-stamp of ACARS txm:s, as we know the pattern and how is mounted on the A/C body.

foootprint map of ACARS-service reveils degraded zone within the same area:
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Old 7th Jun 2009, 15:29
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There is much talk about high altitude performance in this thread. May I remind You that the flight plan called for a step climb to FL370 at SALPU.
To my knowledge there has been no attempt either by HF (Atlantico) nor by relay transmission to get a clearence.

I could imagine that they did so in order to increase their performance.

@Rainboe: absolutely correct.......
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Old 7th Jun 2009, 15:34
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Media make much about autopilot being disengaged. Until recently, one is led to believe, disengaging autopilot in CB was sop. Is the Airbus autopilot of a type that could be expected to cope with wild excursions or would a pilot switch it off if he saw things were becoming hairy? Thank you for your patience.
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Old 7th Jun 2009, 15:34
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Dominique Bussereau the French Transport Minister has been quoted as saying.....

that it is too early to reach conclusions but has confirmed that the speed readings and their impact on the Airbus automated flight system are at the focus of the inquiry.

"Obviously the pilots did not have the right speed showing, which can lead to two bad consequences for the life of the aircraft: under-speed, which can lead to a stall, and over-speed, which can lead to the aircraft breaking up because it is approaching the speed of sound and the structure of the plane is not made for resisting such speeds,"
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Old 7th Jun 2009, 15:59
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The other way around, that the outside air pressure is going to over-take that of the cabin unless the cabin gets recompressed at a rate unpleasant to the pax. Specifically, it means that the re-compression rate of the cabin is higher than 1800ft/min if cabin pressure intercepts outside pressure upon landing. The pressure intercept is managed by the system automatically based on key inputs, one of them the descent rate of the ac. The warning indicates that the pax are heading for an ear pop.
So if the cabin pressure is at 8000ft, this warning suggests that the a/c is descending at a rate such that it would hit the water in less than 4.5 minutes, correct?

Or could this warning also be a result of bad air pressure data from iced-up probes?
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Old 7th Jun 2009, 15:59
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There was some discussion at about midday Sunday 7th June, in posts around #465, concerning thepossibility and usefulness of an automated Mayday facility. The objections seem to be from traditionalist professionals who quote the Aviate, Navigate Communicate philosophy drummed into them at an early stage in their flying career. ANC is perfectly reasonable in situations where the flight crew have the time and space to establish reasonably stable flight, work out where they are and where they can go in the immediate future, and then inform the rest of the world. In such cases early communication may not be of any advantage to that flight or to anyone else. However, there are other situations where very early announcement could be very useful. If coupled to a GPS and other sensors, an automated Mayday could give precise positional and other information; it could produce high quality sound in clear English, without the intrusion of background noise; it could make other aircraft aware of someone nearby who was having to ignore normal separation rules; and if the worst came to the worst, it would give SAR a good position from which to start searching.

On different theme, Interflug speculates (in post #498 at the time of writing):

could someone have tampered with the documented weight in order to stay within margins, avoid timeout etc?
could the pilots have been unaware they were too heavy?
Would any significant excess weight become apparent to the crew once airbourne as a difference between actual and expected Angle of Attack for the current altitude and airspeed? Are instrument displays sufficiently precise to make any such discrepancy apparent, and if so is it the sort of thing the crew would notice and take into account?
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Old 7th Jun 2009, 16:18
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FDR Data

According to german magazine 'Der Spiegel' there is allready a discussion going on between aviation safety experts to implement a system to automatically transmit FDR datas by satellite.
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Old 7th Jun 2009, 16:21
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CNN reports total bodies recovered up till now is 5.

Re weight: F350 with max weight and high temp is not a problem, especially since they've been 3 hrs in their flight.
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Old 7th Jun 2009, 16:37
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Forensic Pathology & importance of post mortem results in aviation accidents

Sadly I think that in relation to this particular incident the role of the forensic pathologists may be crucial in helping determine what actually happened to the passengers & crew and therefore will be a valuable resource for the accident investigators .

There is a wealth of information available on the internet in concerning the discoverys of forensic pathologists with relation to Air Accident investigations.

And Air accident investigators have found crucial evidence contained within post mortem reports that have in the past enabled them to discover what actually occurred to the aircraft and its passengers .

In fact concerning the speculation concerning the recent Russian accident report & the charge that the pilot was in fact drunk while in charge of his aircraft is in fact a highly contentious issue amongst medical professionals . test results can be altered by many different factors .

see below taken from forenscic science international

Interpreting results of ethanol analysis in postmortem specimens

interpretation of BAC in autopsy specimens from the pilot and crew is highly contentious and great care is needed to reach valid conclusions.

Thankfully the fact that bodies have now been discovered can only help the air accident investigators in their quest to find out exactly what happened to this aircraft , its crew and its passengers .
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Old 7th Jun 2009, 16:37
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traditionalist professionals who quote the Aviate, Navigate Communicate philosophy
I do not want to clutter up this thread with an off-topic debate about the supposed pros/cons of a button push mayday.

What I do want to say, however is there is nothing "traditionalist" about the ANC philosophy. I hope that the majority of pilots on PPrune would agree with me here !

It is a very important philosophy, there are multitude of excellent reasons why it is taught to pretty much all student pilots. Correct and professional prioritisation is critical in a flight deck environment, irrespective of whether you are flying a SEP or Jet and irrespective of whether you're flying as single PIC or MCC ops (with appropriate MCC considerations about flight deck level communication of course e.g. DODAR and NITS, or however else you want to put it !).

Last edited by mixture; 7th Jun 2009 at 16:54.
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Old 7th Jun 2009, 16:53
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Brazilian Air Force and Navy had sight of multiples bodies on the water and wreckage from the airplane, yet, awaiting visual confirmation and news from those authorities.
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Old 7th Jun 2009, 16:53
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How Does It Work

Until the causal chain (multiple factors) is established I do hope that we can keep the opinions about good and bad aircraft design out of this thread. That kind of stuff belongs in generic technical discussions.

The how does it work on an A330 stuff is appropriate for this thread.
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Old 7th Jun 2009, 16:58
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@Thermal Rider

'and assuming a descent from FL370 would extrapolate into a descent rate of 9000ft/min or more to trigger the warning'
We have no clue by now about the possible start of descent. Any calculation can only be faulty.

By the way, there is also no indication that the flight was at FL370
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Old 7th Jun 2009, 17:06
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"Hard Turbulence Report: Source?

At various points in this and other thread there has been reference to a message from AF 447 regarding the aircraft being in "hard turbulence" in a storm-cloud system. The very earliest versions of this supposed message even referred to the pilots being "cut off" in mid-conversation, or in mid-text message.

Given that this would be the *only* direct evidence of AF 447 actually being in or very near the storm system (rather than just appoaching it), does anyone have a direct AF / Airbus / BEA source for the "information".

Part of my reason for asking is that some French-language discussion groups (who also can't find a direct source) are suggesting the the "information" is based on a mis-translation of something Airbus said early on about "reports having been received" of hard turbulence, but not necessarily from AF 447 itself.

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Old 7th Jun 2009, 17:20
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Thoughts from an observer

Please forgive in advance intrusion by ex-amateur pilot and frequent passenger.

Two things stand out for me after having followed this discussion from the beginning. The first is that no pilot of the experience of the AF crew would willingly end up in the weather situation they were in. And yet they did. That suggests either a failure of the weather radar, a failure of interpretation, or a weakness in the pilot/radar software interface (which could lead to a failure of interpretation of the weather radar). Other similarly-experienced crews were successfully dealing with the same weather system that night. So what was different about AF 447?

It is striking that crews in this part of the ITCZ have no real-time tools to deal with convective activity other than the onboard radar. PIREPs seem few and far between (and hampered by problems with HF), there’s no ground-based radar of any kind (ATC or dedicated weather radar) to assist, and there appears no current way of getting any detailed information from the weather satellites, which at least would provide a bigger picture of what’s behind whatever the onboard radar is painting. It appears that, by comparison with crews dealing with the same kind of weather in a continental context, crews traversing the ITCZ over the oceans are flying with the equivalent of at least one eye shut.

The other thing I found striking is trying to imagine what that cockpit must have been like with all the alarms going off, trying to make sense of multiple failures happening virtually simultaneously, trying to reset computer systems, and all while trying to hand-fly an aircraft to maintain a very delicate balance between stalling and overspeed without accurate airspeed information – while in the kind of turbulence that’s not a common experience even for the most experienced crews – and at night.

Not getting accurate airspeed information is bad enough in that situation, and would have presented a very difficult challenge all by itself (harder, perhaps, that the one the AeroPeru crew faced – at least they didn’t have to deal with a very narrow margin between stall and overspeed). But having to be computer operators at the same time?

That’s not to say that a Boeing crew would have had things any easier. But there are downsides to automation in any context. Airbus normal law would undoubtedly have saved the Buffalo Dash-8 crew from stalling. But being surrounded by computers, all screaming failure at the same time, couldn’t have helped the AF crew deal with what was already a horrible situation.
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Old 7th Jun 2009, 17:27
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Manual ELT activation?

Referring to suggestions of "push button mayday systems" or "automated mayday systems with GPS reference" in previous posts:

Would manual activation of ELT be an option once a crew realizes they are unable to regain control of the aircraft and the aircraft is doomed to crash/ditch?

In a case like this the SAR team would have saved 5 valuable days and possibly could have saved lives of any survivors.

Is manual ELT activation as a last resource ever discussed / considered during crew training?
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Old 7th Jun 2009, 17:29
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ACARS Transmission Method


The satcom has got to be pointing up.... We're lucky we got a message in the dive at 2014z (if that's what happened.)
Either we were lucky, or should one conlcude it still *was* pointing up when handing out this msg?

While I have been following both threads in detail and know it ws mentioned, but I do not recall exactly whether the transmission method of ACARS msgs had been firmly established?

EDIT: I see this has been at least partially answered while I typed. Ignore my question.


Last edited by rattler46; 7th Jun 2009 at 17:42.
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Old 7th Jun 2009, 17:31
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FBW alternate law
Rudder Travel Limiter Fault
So, right at the point of alternate law, in manual flight, the important bit of kit which stops any strong input to the rudder pedals shearing off the rear flight surfaces failed? Or am I reading into this too much.
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Old 7th Jun 2009, 17:35
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Amidst all the speculations thus far, I find it strange that nobody has jumped onto a story posted much earlier by some-one who spoke to some passengers who were on the south bound leg of this A/C. He said they said there was a "black-out" during the leg, but all came right after a while. Now, was this problem snagged (reported) after landing, and released as "unable to duplicate snag"? Could this same "black-out" have occurred again, this time in or near a CB ? Whatever this black-out was, as far as I can remember, if one does get something resembling a "black-out" (any major system trip-off), it never was a simple problem...usually the start of a multiple failure of sorts. What if.......
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Old 7th Jun 2009, 17:41
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Surely, sticking to the South American east coast for a few hundred miles more, before heading across the water would reduce the risk.

Ok, it would cost a bit more.
I believe they didn't have any deviation fuel because the PIC didn't request any in RIO.

If they had, I'm sure AF would have pointed out that fact by now.
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