Jet Crash Forum

Does someone know which ACARS failure messages were sent in which order? Please post them if possible.

See:

http://www.pprune.org/rumours-news/376433-af447-4.html

and discussion in that forum.

-rer47

You must keep in mind these messages were for guys and gals to repair problems with the aircraft when the thing landed, not some sort of substitute for the recorders. People in the know say they're arriving in order but I'm really wondering if it was built to cope with a massive amount of information in each reporting interval (like, for example, 1 minute cycles) and I'm just a interested, non-airline person with a little bit of piloting interest.

In brief, what the messages say to me seems to be

• The auto pilot turned off.
• The control system told the pilots the rules for flying were going into an alternate setup to "normal"
• messages to the captain and first officer position about airspeed(not sure if this is too slow, too fast or the two disagree with each other.)
• the auto throttle came off (this is how I'm taking "auto flight a/thr off" remark. And again, if the auto pilot was going off this would as well giving control to the pilots.)
• messages that part of the control system was having difficulty(with the data it's getting or receiving data at all is up for debate)
• a second round of messages to the captain and first officer position about airspeed(not sure if this is too slow, too fast or the two disagree with each other.)
• a message that the rudder limiter has a fault (which some have said is a usual effect of coming out of normal laws and the auto pilot coming off because of airspeed errors. But maybe not in light of tail problems on Airbus in the past.)
• further messages that flight control systems need attention
• there's a third round of messages about air speed to pilot and first officer
• the system for showing airspeed to the pilots and the computers is noted as having differing figures between different measuring devices on the plane(this is shown so they know what is displayed might be in error and they should go about checking airspeed, checking they're not going to fast or two slow for the aircraft weight, and looking for a reasonable indicator of airspeed that might be operating. If the computer isn't working they have to look for non-computer means.)

That was all in the one minute around 02:10GMT. I read the screens blink different messages at the men and maybe a few audible alerts as stuff was presented and the auto pilot turned off.

From 02:11GMT on to 02:14 there are further messages that the computer flight control system is not coping with data and is in fact shutting off different parts. And the final message is a notice that decent is too rapid for the settings of the pressure in the pressurized parts of the plane. (Others in news articles point that it's decompression but I'm not really convinced after reading the other forum's conclusions. It's an advisory message that inside pressure will be lesser (that of the pressure of 8,000ft common to leave it at while crusing) than outside (under 8,000 ft values) in short order. On a normal day it probably wouldn't happen but it would prompt a setting to be changed to equalize a bit faster before landing.) I haven't listed the messages out because I'm expecting it was already past the point where they were saving the aircraft. These were the dying airplane's final messages like those on the Space Shuttle Columbia. I have a retired airline friend saying one minute is probably all it took to fall from 35,000ft to the surface so three minutes is somewhat of an eternity in that light.

The failure reports began eleven minutes after one of the three pilots texted a quick note on a different system (at 02:00GMT or so) that they'd been in turbulence. And that was probably a "breather minute" before they found the shaking starting all over. I think at least since 01:45 or so they'd been into some weather and were minding the shop, as it were. So maybe the computer auto pilot going off and handing the flying over to them wasn't a shock. They took a risk to press on with the flight vector and approach the storm line. Maybe with the thought that it was after dark and must be dying down?

The pulse of information to Air France (which we don't really know had everything from 02:10 or if each minute was sent discretely) was sent to the satellite and at 02:14+ the plane itself had to be upright enough to connect and send and the system still had to be powered. So that in itself is somewhat curious. Air France didn't release further messages of things like engines dying and electrical shorts or they didn't get them because the ACARS system was not pointing where it could send them to a receiver. We got a flurry of messages that the computers showing flight info were having a hard time of it.

Looking at the structure of the printout documents the Air France released to French TV 2 I begin to think Air France didn't release anything more than they had to to satisfy the media. The pages appear to be 28 and 29 of 256. Page 29 has the latter data than 28 so it's somewhat possible there's more past the cabin pressure advisory. That almost seems too many pages.

There's been some sketchy report that earlier in the day the plane may have experienced what a passenger called a blackout. Some people over on the pilot's forum are doubting it. But page 27 might be an interesting read.

One tiny additional note, if you trust the search that produced these items, June 1st's AF447 did have one more "normal" note in the ACARS log. It was that something was up with the waste system around forty-five minutes after takeoff. I don't know enough to say specifically what was wrong. It's considered over on the pilots forum as too mundane to examine fully. It's probably only a "human interest" story that the passengers might have been inconvenienced by a misfunctioning toilet early in the flight.

(My airline source told me planes now store wastes for disposal instead of dumping them to air. And they don't leave if the drains are leaking. So any theory that the plane was trailing some ice fog for lighting to strike or the tail iced up with super-cool toilet fluid was 86'd by my friend. The mechanics know the hazard was possible...)

The question is whether or not there are more pages relating to this flight, or whether the other pages are each relating to other AF flights (usually one expects 0 to 3 ACARS messages per flight).  I personally think that the most likely explanation is that this is the complete transcript starting with the pages relating to the incident.    It isn't clear to me whether there might be an additional page of errors before (this would be highly significant if there was) but at the moment, that seems unlikely.

At the moment my assumption would be that these reports are complete, but that this assumption is subject to change if new information emerges.

What I'm going on here about the page 28 of 256 is I do expect that this document made for French TV was searched from the database with the aircraft's identification number. That was done at the main database place, wherever that is. Up top of the screen printout is the lettering "AV FGZCP" and I do believe that is how the search is limited to only that aircraft. Anything else would be pretty confusing for someone wanting to summarize the problems with one aircraft of the fleet over time. So I'm sure any database worker at the screens there with experience can query this info up properly.

The little bit I read about the ACARS system, this sort of screen and summary can be accessed plane-side somewhere in the cockpit for immediate use. The satellite transmission was just a sort of backup for the home office to get a big picture of maintenance needs as they occurred. It's a sweet little set up. It uses plane speed to know if it's a new flight by take-off speeds lasting more than half a minute and it also records know when it's landing the same way. No one in the plane has to pay attention to it except to select a choice of radio or satellite systems. And it can specify if something happened in flight or by some bozo knocking around stuff at the terminal.

At the bottom of the "first" page of flight 447, with the oldest times and date of 5/31/2009 is the flight "AF 444". At first look this might look it's not related to AF 447 but let me break down a little of how some, I know not all, airlines do their thing-- What you got to know about "flights" is that the airplane flies in to a city with a flight number, lands, gets services and all, and leaves with a new flight number. But it is the same plane. The search with the "tail number" of that plane will bring up different "flight numbers" each day. And in some cases the airline has the same flight numbers repeating each day to the same city. I do want to know that nothing happened on AF444 going into Brazil because it would mean the aircraft was fit to fly.

However, I think that the Air France people releasing only two pages was only to simplify things severely for the TV reporters who (as we've seen so far) will get things so wrong as to cause people to be afraid to fly. And all the people theorizing what happened without the recorders (like me) would be looking back months for some minutiae to blow out of proportion.

Chech the timestamps,  Event the 5/31 messages are after takeoff.  However, it isn't unusual for a plane on a long trip to send out three or fewer ACARS messages, and I currently see no reason that a lavatory fault would be implicated in the crash However, time will tell.......

For mundane, toilets do take it. So the toilet thing would have been the usual "oh we got to fix that" when they got to France. But if it's electrical... My retired airline guy says there's fans and stuff that could go wrong. I'm put in mind of the electrical fires that burned insulation for hours unseen before dripping melted plastic on the pilots awhile back. The entertainment wiring shorted and started a fire. Further tests showed the choices manufacturers were making were less than ideal. More like a flying tinderbox. Is that flammability problem corrected by the 2005 construction of the plane? I just at least wanted someone with the Airbus booklet to say what the specific code for the waste/water error meant and then maybe someone else would be able to say it was or was not something vital. Or, near to something that starting going wacky about three hours later. If all that is somewhere that does not have air to burn, fine then, the air-john was the least of their worries.

They are water/waste messages regarding the lavatories.  Barring further evidence of a connection to the crash, I am inclined to ignore them.

There is extensive discussion on the ACARS messages on PPRuNe.  The key issues are the chapter numbers associated with the messages and in some cases maintenance engineers have supplied more information.

What maybe we can't ignore is how much rattling the plane took prior to the 02:00 text about turbulence. They thought enough about it to, in essence, have one of the two or three pilots on the deck at the time to "phone home" about it. What sort of problems can a plane of this design get from taking a good banging around? It's like having a set of networked computers that fly. I don't seriously expect Airbus took any prototype test plane into prolonged turbulence. Maybe the Australian mini cockpit fire is a good indication of how these glass cockpit planes are going to age. Not gracefully might be the answer.

You can see ACARS messages very similar to those from AF447, and how they correlated to Flight Data Recorder and Cockpit Data Recorder content here:

This is the Australia Transportation Safety Board prelim report regarding an A330 incident 8 October 2008 when the ADIRU's went "berserk" and flew the plane through maneovers causing injury to 74 passengers and crew.

http://www.atsb.gov.au/publications/inv ... prelim.pdf

Now, consider that AF447 nighttime/weather might have made a visual horizon reference (out the cockpit window) difficult, and . .

who, other than left-brain oriented engineers and some pilots, give a rip about ACARS messages?

We, the passengers of 447 and those who cry non-stop for us want to know who killed us.

Was it "fate", "the weather", "God", "Airbus", "Air France"?

Could our pilots have saved our lives?

Wow kate, you almost take my breath away!

"Who ... give [sic] a rip about ACARS messages?"

I've been trying to follow your thinking, but my brain isn't agile enough.  You "cry non-stop" to know "who killed us [sic]" -- and in the same breath, you contemptuously dismiss what may be our only hope of answering the question!

From your "elephant" thread postings, it appears to me that you have already conducted an investigation (by reading news stories over a 10-day period?), and determined that the primary cause of the accident was the decision of the cockpit crew to fly into a weather system beyond the capacity of the flight or the crew to negotiate safely, and that the crew knew (or if they didn't know, were negligent in not knowing) that this course of action was dangerous.  Apparently, you don't "give a rip" about the ACARS messages, because you are all-knowing and all-wise.

To answer your question, the only people who "give a rip" about ACARS messages are those of us who (A) care deeply about aviation safety, and (B) want passionately to know the truth, in order (C) to do everything that can be reasonably done to prevent a repeat of this disaster, while making the aviation safety system stronger.

What ACTUALLY happened in the last half-hour of this flight?  Until and unless the recorders are found, humanity has exactly two sources of factual knowledge:

1)  recovered wreckage and remains
2)  the ACARS messages

It is because of the ACARS messages that the world knows the plane's course with some confidence and precision.  It is because of the ACARS messages that we know that in the final few minutes, instrument and flight control systems were reporting fault conditions.  If the flight recorders cannot be found (sadly, a real possibility), the ACARS messages will probably offer our best hope of learning from the accident how to improve aviation safety.

If one of the ACARS message said "PILOTS MADE STUPID CHOICE", then kate would "give a rip" about them.  Unfortunately for her conviction, these ACARS messages suggest the possibility (not conclusively prove) that from a condition of relatively normal controlled flight, the aircraft instruments may have failed in a way that suddenly confronted the pilots with a situation that, perhaps, even the best and most skillful of flight crews could not have overcome.

Really, if any one of us decides that we want to remain ignorant, a great way to do this is to reject every source of knowledge that doesn't confirm our prejudices.