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AF447

Old 14th Jun 2009, 18:02
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After trying to read through the many pages here I have a couple of points/questions that I would like to bring up....

1. If this situation came about due to one of the factors belonging to the pitot tubes and it was indeed similar to previous documented cases then...can and will they not retrieve the ACAR's fault reports, or even the status/ecam faults to see if there is a similar sequence of events being triggered and recorded at the start of this sequence?

2. If as the situation progressed and they eventually found themselves in direct law trying to control the a/c with the joystick....how much of an effect can moderate to severe turbulance along with the possibility of unusual attitude have on controlling a joystick? Is there not the extreme possibility of the joystick being bumped constantly with the hand while trying to use the thumb and finger to control this situation. Being on Boeings for 12 years (727 and 757/767) and never flown a Bus I would find it seeming difficult to maintain a steady hand in this situation whereas with a control column you have much better chance of dampening the turbulent effects with your body and thus lessoning the chance of overcorrecting and let alone misguided imputs at every bump. Is this a plausible and sensible thought?

As a side note I am also currently studing to take my JAR exams to convert my FAA ATP and I must say this is all so very fitting in application...in a serious and sobering way.
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Old 14th Jun 2009, 18:06
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In 2006 I was discussing the Toronto accident with an Airbus employee. He suggested that a major change resulting from it might be making the use of AT compulsory unless inop or recommended by ECAM/paper procedure. Obviously Airbus has thought better – introducing this kind of major change to the way the Buses are operated could be very costly!
Today there are already rumors that insurance companies might have to foot a bill of up to 750 million USD. And they have to recuperate the money themselves from somewhere… Correct me if I am wrong, but I have a certain gut feeling that this nuclear sub is roaming the depths not to find the FDR and/or CVR but to MAKE SURE they are not found by the right people, that need them so badly.
IN a world where MONEY MATTERS you and me are only pawns on a huge board.
No government/regulatory agency will stipulate that an a/c must be 100% safe. Because it will never get off the ground and make money. So most a/c are 99.99999999999999999999% safe. Or this is what we are told. And in order for everybody to make MORE money, we got rid of the flight engineers, we accept ab-initio CPL holders to fly FBW a/c with less than 500h career time, we accept maintenance outsourcing, etc. etc.
I don’t intent staring the blame game. But we, professionals should help the general public become more and more aware of the issues facing our industry, like THE GUY who spoke up after he landed successfully on the Hudson….
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Old 14th Jun 2009, 18:10
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Probably cause...

DC-ATE:
Let's just list the "Probably Cause" now and save all this bandwidth of speculation.

The Probable Cause of the loss of AF447 was due to the aircraft having problems with the pitot static systems in an area of storms that caused the pilots to lose control of the aircraft because of erroneous airspeed and altitude indications, resulting in an upset from which they were unable to recover.
I would humbly rephrase it:

The Probable Cause of the loss of AF447 was due to the aircraft having problems with the pitot static systems, the complete failure of all IR's and (maybe the partial) failure of the ISIS in an area of storms that caused the pilots to lose control of the aircraft because of erroneous (or no) attitude, airspeed and altitude indications, resulting in an upset from which they were unable to recover.

(agree with you Safety Concerns, what disturbs me more is the failure of all IR's...)

V.
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Old 14th Jun 2009, 18:12
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ChrisVJ:

That was the normal sequence of events during a lightning strike in the old turboprop days. Strike on the radome, takes out the radar and exits through the back somewhere.

It has happened to me in the past more times than you have had a moose steak.

I doubt it has anything even remotely to do with AF447.
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Old 14th Jun 2009, 18:26
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2 weeks in to the investigation and some of you are already talking about "Probable Cause".

Unbelievable.

Thankfully BEA will be more open minded as to the events surrounding this accident.
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Old 14th Jun 2009, 18:27
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Originally Posted by S Steve
BOAC

Perhaps DG stands for Directional Gyro?
I'm very familiar with a 'DG' - 44 years or more! That's the one that spins 'up and away' from you so that if it comes off its bearings it won't smack you in the ...............

It is the DG in an inertial display I am stuck on. Do we assume:

a) The prof is wrong
b) the ATA is wrong
c) you and I are wrong?

I think the ISIS message is because it lost valid inputs from its Air Data sources. These come from the Standby system ADMs (Air Data Modules that convert pitot and static to digital close to the probes/ports)
- absolutely, but why the ATA 'gyro' reference? Are there pitch/bank limits to the system?
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Old 14th Jun 2009, 19:02
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I think the ATA is just plain out of date. When ATA100 was introduced there were only gyros, and now its IRUs it uses the same ref for both.
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Old 14th Jun 2009, 19:16
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stains on spoiler panel

Of course one expects some grime underneath, depending on how anal the maintenance people are, but there is a lot of grime on the top panel as well, and distributed in a matter consistent with it washing up on the panel while in a debris field.

-drl
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Old 14th Jun 2009, 19:22
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@STEVE
The ISIS is one display that takes the place of the Standby Instruments on older aircraft. It doesn't have a DG, it has a Ring Laser Gyro.
I think the ISIS message is because it lost valid inputs from its Air Data sources. These come from the Standby system ADMs (Air Data Modules that convert pitot and static to digital close to the probes/ports
)

maybe in Stockholm they feed an STANDBY SYSTEM with values from ADM's.

DESCRIPTION
The back of ISIS is fitted with two pressure connectors:
- One is connected to the standby pitot probe for total pressure
acquisition.
- The other one is connected to the left and right standby static probes
for static pressure acquisition.
ISIS is fitted with:
- One pressure module,
- one inertial module,
- one computation module,
- one display module,
- and one interface module.
The pressure module is connected to the total and static pressure
connectors.
Each pressure line is connected to a pressure sensor in the pressure
module.
The inertial module is composed of three single-axis rate gyros and
two acceleration sensors.
The computation module performs the computing and graphics
generation functions.
The display module is fitted on the front face of ISIS. It is of the
Liquid Crystal Display (LCD) type.
The front face is also fitted with
several knobs for operation purposes.
The interface module is composed of:
- a filtering board linked to an electrical connector at the back of ISIS,
- the 28VDC power supply unit,
- the interface board which links the pressure, inertial, computation

Thats why it is called STANDBY, apart from normal ADIRU SYSTEM
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Old 14th Jun 2009, 19:28
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Really trying to understand this Alternate law on the flight controls here.
These SLF questions are really useless at this point and provide no positive influence or information to this thread.
Can you guys tone it down a bit so some real crew can read through this and maybe try to have a understanding to what has happened without having to read useless information?
I think I seen a thread on jet blast that may be more in line.
Not saying that what you have to say is not news worthy, but please leave this thread to the front end crews.
Some of us have been around for a long time and are more interested in facts, procedure, known issues, not in what if this situations.

Last edited by Earl; 14th Jun 2009 at 19:50.
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Old 14th Jun 2009, 19:42
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Originally Posted by Skiperica
Excuse me if my question is stupid or trivial or disruptive in your discussion. I´m not a pilot, not even a couch pilot and I will accept if my post is deleted.


I´m puzzled by the different lat/lon positions of "Last ACARS 0214Z" used in different maps, charts and data from Brazilian Air Force and others. I think this is important, because Força Aérea is referring to that position measuring distances, e.g. of debris found. Here at pprune and in other discussions there are conclusions drawn from this distances - e.g. if the Airbus could have been broken in high altitude or not and in what weather conditions AF 447 really was at 0214Z.

I found different data concerning last ACARS:

1/ Wikipedia, pprune:
Last ACARS 0214Z
3°34'40"N, 30°22'28"W

2/ Last Report ref. to Brazilian Air Force
"Ultimo Reporte"
3°16'28"N 30°22'28"W

Wikipedia does not provide a reference for this particular information. I also could not figure out a reliable source in many days of research. Not even where this "information" first occurred. It has been assumed that lat/lon position is data coming with the ACARS by satellite transmission, but I cannot find a reliable source for this assumption either.
Brazilian Air Force uses different positions for "Ultimo Reporte" in different plotting they provide, one of them suggesting "Ultimo Reporte" being in about 167km distance from TASIL: http://www.pprune.org/rumours-news/376433-af447-49.html#post4986435 (see lower picture).

Thus I have the following 2 questions:

Do/could ACARS messages technically include information about lon/lat position?
Are the ACARS messages that have been published truncated in a way that would suggest Air France to have additional information about exact position transmitted by satellite?


Thank you for the opportunity to learn!
Skiperica/self loading freight (-;

You ask very good questions. All these "positions" appear to be only estimates based on where AF447 should have been had they continued on their track from INTOL to TASIL on the UN873 airway.


I don't think anyone has any actual information on the actual position of AF447 when the ACARS messages were sent, or where they actually entered the sea.

Someone please prove me wrong.
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Old 14th Jun 2009, 20:04
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ISIS

BOAC:

Are there pitch/bank limits to the system?
Roll / Pitch -180 to +180...as stated in the AMM.

A330Tech.
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Old 14th Jun 2009, 20:14
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Do ACARS messages technically include information about lon/lat position?


No

Could ACARS messages technically include information about lon/lat position?


Assuming, that no VHF coverage is avail. ACARS is communicating via SATCOM. To contact the satellite, the A/C has to know his position in regard to the satellite to adjsut the dish.
ACARS is linked with most of the computers , so it should be easy to track it by sending LAT/LON datas.

Are the ACARS messages that have been published truncated in a way that would suggest Air France to have additional information about exact position transmitted by satellite?
Maybe, but till now all flight trackings are based on OOOI messages and calculated flightplan. I think there are also some legal issues.
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Old 14th Jun 2009, 20:17
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Thesandbox - In response to your second question;
No quite simply. The joystick has no feedback. Even if the plane was all over the place, the joystick would not move at all. There is no feedback. Of course, I haven't flown a 'bus in severe turbulence in direct law, but as you were asking about the fact that you can't use your "body strength" etc then it makes no difference as there still isn't feedback.
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Old 14th Jun 2009, 20:22
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A33Zab

A330 tech: please translate the following ACARS report from you AMM or fault isolation manual:

Quote:
34 43/06 WRN WN0906010210 344300506 NAV TCAS FAULT 09-06-01 AF 447

Thanks,

GB
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Old 14th Jun 2009, 20:31
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ISIS

BOAC:

Quote : "Is there any (unlikely?) cross-tell between ADIRUs and ISIS?

EDIT: I do query PBL's diagnosis of the ISIS fault, however "At a similar time, the DG in the stand-by flight instrument system complains." - what is a 'DG'?"

The ISIS is a self containted intrument, no one knows what exactely is inside because stuff is still military classified (when there's a glitch with it, maintenance sends it straight to Airbus. There's NO opening the case !

contains Gyro and accelerometers (says the FCOM)

It gets direct pitot and static inputs from the stby probe and port. There's no air data computer inbetween.

IT ALSO GET'S INFO from ADIRUs 1 and 3 !!
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Old 14th Jun 2009, 20:32
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Who, in their right mind therefore, decided it was a good idea to fit three identical tubes, all from the same manufacturer...
Ah, probably the same people who decided to put two identical engines from the same manufacturer on the airplane....
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Old 14th Jun 2009, 20:36
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The aircraft needs two identical-ish engines for stable flight. The pitot tubes, however are somewhat different.

I fail to see the logic in using three identical tubes, purportedly for safety reasons, when three dissimilar ones would reduce the chances of all three failing due to a design flaw/stock fault.

Little additional cost but reduced likelihood of complete failure. It's a no-brainer as far as I can see.
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Old 14th Jun 2009, 20:37
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@graybard

MAINTENANCE WARNING REPORT
---------------------------
A/C ID DATE FLTN
XXXXX 090614 XXXXX
ECAM WARNING MESSAGE
+--------------+
GMT PH ATA SEQ DESCRIPTION
195X 06 27 90 400 F/CTL SENSOR FAULT

this is the normal format we get. To translate yr format

34 43/06
ATA chapter 34-43 flightphase 6
WRN WN0906010210
Warning Date 09.06.01 0210UTC
344300506 NAV TCAS FAULT
Failure code 344300 SEQUENCE 506 NAV TCAS FAULT
09-06-01 AF 447
IDENT


Normally no big deal .
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Old 14th Jun 2009, 20:37
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Originally Posted by barrymung
As I understand it, the plane was fitted with three identical pitot tubes. Presumably, the reason 3 are fitted is in case one or more fails.

Who, in their right mind therefore, decided it was a good idea to fit three identical tubes, all from the same manufacturer, all of the same type and presumably the same date of manufacture??

If one tube had a stock fault, all three would have it.

Surely it'd be far more sensible to use three different tubes from three different manufacturers?

That way, if one failed, chances are the remaining two would be unaffected.
Well, there are various practical problems with dissimilar designs, especially for systems that need to have data in agreement from multiple sources in order to assure safe operation. With three different probe designs you'd get far more ADR DISAGREE type situations with the increased hazard that represents.

You also need to spec the dissimilar designs, and the performance specs would presumably be identical. Since the state of the art for pitot probe design is mature, chances are you'd get very similar designs even from dissimilar vendors.

You'd also end up with the same environmental spec, so the same conditions which would overwhelm one probe's heater capability (if that happens) might very well overwhelm all the dissimilar probes.

And, finally, they didn't put all their eggs in one basket. The ISIS/standby is using a different means in that the standard probes have ADMs at/near the probe, while the ISIS is (I understand) plumbed traditionally with the sensing as part of the ISIS unit. So if you were to have some kind of catastrophic design flaw that took out every ADM the ISIS should still be running.

I don't think the air data system designers are as clueless as you seem to think.
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