AF447
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Nothing new really. It's been suspected from the very begining.
let's suppose for one second they went through the same incident Qantas did in the kind of weather they were flying. You're toast.
The fact that AF shows full confidence in the Airbus is quite understandable.
Imagine what trough we'd be in if the fleet was grounded. That would be the death of us.
let's suppose for one second they went through the same incident Qantas did in the kind of weather they were flying. You're toast.
The fact that AF shows full confidence in the Airbus is quite understandable.
Imagine what trough we'd be in if the fleet was grounded. That would be the death of us.
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DC-10 fleet was grounded on less evidence than we have so far on the A-330. L-188s kept flying despite two in-flight shreddings because a California-based airline had only Electras in their fleet. Economics dictate safety policies.
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carjockey: I thought the Times chose a rather sensationalist headline by referring to the "main suspect" as a "computer bug". While some hardware or software bug has not been ruled out, what the article text really talks about is the possibility the flight control system was receiving erroneous information from the sensors rather than a computer bug per se. As someone mentioned many msgs ago GIGO, garbage in, garbage out. It is quite possible that had a human computer been given the same information and situation that AF447 faced he/she may not have reacted any better.
Thanks to all for confirming the photo that I posted was of a crew rest area in the cargo hold. It probably was discussed earlier with a link to the photo but I missed the link before it got deleted.
I suspect that the cargo area was opened before it hit the water and other bins were probably part of the debris field. Do we recognize other bin pieces in the other photos?
I suspect that the cargo area was opened before it hit the water and other bins were probably part of the debris field. Do we recognize other bin pieces in the other photos?
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My personnal feeling and I'm very sorry to say that, is that some people within official bodies in France are praying that these boxes shall never be found.
A lot of fishy things coming up with the bodies and debris.
As I said on 2nd June
On CMC and ACARS
This system can be very customized. AF knows much more than they admit. They have been talking to their legal team right from the start. They will spoon-feed us the info when they are told its ok by their lawyers.
This system can be very customized. AF knows much more than they admit. They have been talking to their legal team right from the start. They will spoon-feed us the info when they are told its ok by their lawyers.
I would love the moderators to migrate the technical side of this discussion to Tech Log and leave this forum to not so technical speculation and rumors regarding this disaster...
I personally believe there was nothing wrong with the plane until it entered the severe weather. How and why it entered? To me the operational side presents much more opportunities for discussion...
We, professionals need to understand how come this exactly flight got to prove the 10000000 millionth probability in the statistics exercise...
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ISIS
ISIS, stby altitude, altitude indications
As written (by me among others) in previous posts, the ISIS is a self contained instrument providing Airspeed from stby pitot, attitude from internal gyros, Altitude from STBY static ports, and slip/skid info from accelerometers,
ISIS IS the stby instuments !
direct inputs from the pitot and from the static ports are provided. No computer inbetween !!
Also, the FMGC provides a "backup altitude" which is provided from the GPS's on the DATA / GPS page. It's not a pressure altitude, but nevertheless gives a good idea of whether you are at 35000' or 2000' !!
The QRH checklist for "Unreliable airspeed" suggests to use this it by the way.
As written (by me among others) in previous posts, the ISIS is a self contained instrument providing Airspeed from stby pitot, attitude from internal gyros, Altitude from STBY static ports, and slip/skid info from accelerometers,
ISIS IS the stby instuments !
direct inputs from the pitot and from the static ports are provided. No computer inbetween !!
Also, the FMGC provides a "backup altitude" which is provided from the GPS's on the DATA / GPS page. It's not a pressure altitude, but nevertheless gives a good idea of whether you are at 35000' or 2000' !!
The QRH checklist for "Unreliable airspeed" suggests to use this it by the way.
If this aircraft was equipped with ISIS, it was surely also equipped with Back-Up Speed Scale and Back-Up Altitude, that displays on PFD's and gets information from AoA probes and GPS, respectively.
This is very important, once Back-Up Speed Scale and Altitude are only displayed when ALL ADR's are switched OFF. The old procedure (for the stand-by horizon equipped aircraft), would call for the trouble-shooting of the IR fault, and in case of all confirmed to be faulted, one would be advised to switch off those connected to Captn PFD and FO PFD, i.e., IR1 and 2. This would allow the aircraft to revert to Alternate Law.
This system (although brilliantly designed) seams to work fine in rather smooth air and on flight simulators, but I find it very difficult to see it properly working in a heavy turbulent environment, as seemed to be the case of AF447.
Last edited by aguadalte; 19th Jun 2009 at 12:18. Reason: to substitute ADIRU by ADR
Per Ardua ad Astraeus
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Originally Posted by agua
Just a word to clarify that ISIS doesn't receive "attitude from internal gyros", it receives inputs from ADIRU1 and 3. It also receives inputs from Stand-By Pitot and Stand-By Static Probes.
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ClippedCub:
I stand corrected !
Was thinking of other types used I guess. From memory, off one of these Disc. Cha. or Nat. Geo. footage...
Yeah I know, not quite first hand !
I stand corrected !
Was thinking of other types used I guess. From memory, off one of these Disc. Cha. or Nat. Geo. footage...
Yeah I know, not quite first hand !
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ISIS
aguadalte:
The problem, as said earlier, is that ISIS containts are classified. I know it sounds weird but again, no one opens up this box !!
While it is true that it gets inputs from ADIRU 1 and 3, it is also true that it contains gyros !!
What inputs from ADIRUs ? I have no idea because the Airbus doumentation does not describe this. It could be to compare data, or to receive inputs from AOA and such....
It also is linked to ILS receiver 1 for example as you can display the LOC/GS sacles and diamonds.
As a matter of fact, ISIS needs to "align" its ATTitude on power up, and has an in flight ATT re-initialization button as well.
So the GYRO, Attitude information IS definitely self contained !
It is a BACKUP instrument. We know how to use it, we know what can go wrong with it, we do not know how it works inside !
Do we really need to ? not so sure.
By the way it is powered by BOTH the DC ESS bus and Hot Bus 1
Just a word to clarify that ISIS doesn't receive "attitude from internal gyros", it receives inputs from ADIRU1 and 3.
The problem, as said earlier, is that ISIS containts are classified. I know it sounds weird but again, no one opens up this box !!
While it is true that it gets inputs from ADIRU 1 and 3, it is also true that it contains gyros !!
What inputs from ADIRUs ? I have no idea because the Airbus doumentation does not describe this. It could be to compare data, or to receive inputs from AOA and such....
It also is linked to ILS receiver 1 for example as you can display the LOC/GS sacles and diamonds.
As a matter of fact, ISIS needs to "align" its ATTitude on power up, and has an in flight ATT re-initialization button as well.
So the GYRO, Attitude information IS definitely self contained !
It is a BACKUP instrument. We know how to use it, we know what can go wrong with it, we do not know how it works inside !
Do we really need to ? not so sure.
By the way it is powered by BOTH the DC ESS bus and Hot Bus 1
Last edited by captainflame; 18th Jun 2009 at 19:26. Reason: Added info.
BOAC;
The ISIS is powered off the DC ESS bus with an auto-backup to Hot Battery bus 1.
While one can guess, I do not know what is meant by the terms, "accelerometer" and "gyrometer" in the "ISIS" box. The key in that understanding is, of course, whether or not if ADIRS 1 & 3 fail, does the standby horizon fail?
Originally Posted by Asking about ISIS
I have been asking this for a while with no definitive answer - are you DEFINITE there is no l@ser gyro unit in ISIS? Others seem to think there is, and that the ADIRU inputs are pressure values only. SOMEONE in the Airbus world must know, surely? No wonder people are confused!
While one can guess, I do not know what is meant by the terms, "accelerometer" and "gyrometer" in the "ISIS" box. The key in that understanding is, of course, whether or not if ADIRS 1 & 3 fail, does the standby horizon fail?
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Could it be that the data exchange with ADIRUs is only for comparison? Otherwise I am not sure why the ISIS box would contain its own gyro/accelero if not to provide independent information.
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BEA debris and drift graphics
Quote from the BEA website regarding these images:
"During the third Press Conference that was held on 17 June on the progress of the investigation into the accident to flight AF 447, the BEA presented the sea search operations that are under way. It contains a map of the locations of the airplane debris, including the fin, that were recovered from the surface of the sea. This debris field corresponds to a relatively small area with a drift towards the north."
June 10
June 9
June 8
June 7
June 6
June 6-10
"During the third Press Conference that was held on 17 June on the progress of the investigation into the accident to flight AF 447, the BEA presented the sea search operations that are under way. It contains a map of the locations of the airplane debris, including the fin, that were recovered from the surface of the sea. This debris field corresponds to a relatively small area with a drift towards the north."
June 10
June 9
June 8
June 7
June 6
June 6-10
Last edited by DorianB; 18th Jun 2009 at 21:06.
lomapaseo;
With one exception, I don't recognize other bin pieces but in the collection of parts on display there is/are:
- One exception re "bin" - what is probably a section of the F/A crew module marked "FWD"; I suspect it comes from the forward, left-hand side.
- Several overhead bin covers
- a longish, narrow section with two "porthole-ish" holes at the ends - I suspect this is part of a cabin bulkhead structure (from which the curtains hang, etc, likely between J-class and Y)
- the structure with the video screen is one of the bulkheads in Y-class which either divides the Y cabin or is part of the J-class/Y-class divider.
- the flourescent box is either the doctor's kit or the defibrilator. I note that it is essentially unscathed and still closed, (not broken open in the accident sequence). This kit was kept near the front of the aircraft but we do not know the location of this kit on the AF330's.
- there are a great many other smaller parts, all of which seem to be the same honeycomb structure - no surprise, as such structures float...
From the available information (photos), these large, intact parts exhibit fracture, tear or blunt force patterns (including being struck by other parts as described earlier) but not large deformation patterns or a shattering into small fragments normally seen in a high-speed impact with water.
What the rest of the structure may exhibit is not yet known.
The information supplied by Great Bear is encouraging in the sense that loss of the CVR/DFDR signals may not end prospects for recovery. This still recognizes the significant task at hand and when/if discovered, the difficulties in recovery.
BTW, the galley, which photos showed up on the 17th with the skin-diver, was actually found on the 7th, as indicated by this PPRuNe posting:
Galley photo June 07
ClippedCub;
Thanks for your descriptions - I apologize for leaving my question and post open to interpretation regarding the suggestion of a "flat" spin - it wasn't yours I know but it has been made. I understand the dynamics of swept-wing flight and what happens in the stall/spiral/spin, (dynamic chord on the outside wing etc) but I wanted to understand how, and what the potential was, for a transport aircraft to enter/sustain a flat spin, where the nose is level or higher than the tail, given "normal" dynamics. In other words, with structural damage as per the BOAC 707 over Fuji which was a falling brick, all bets are off. To me, a steep nose-down attitude reaching very high speeds very swiftly and requiring great altitude to recover from, is far more likely an outcome from any non-recovered stall.
I'm using Davies' book but if you can point to other literature, I would be grateful.
PJ2
I suspect that the cargo area was opened before it hit the water and other bins were probably part of the debris field. Do we recognize other bin pieces in the other photos?
- One exception re "bin" - what is probably a section of the F/A crew module marked "FWD"; I suspect it comes from the forward, left-hand side.
- Several overhead bin covers
- a longish, narrow section with two "porthole-ish" holes at the ends - I suspect this is part of a cabin bulkhead structure (from which the curtains hang, etc, likely between J-class and Y)
- the structure with the video screen is one of the bulkheads in Y-class which either divides the Y cabin or is part of the J-class/Y-class divider.
- the flourescent box is either the doctor's kit or the defibrilator. I note that it is essentially unscathed and still closed, (not broken open in the accident sequence). This kit was kept near the front of the aircraft but we do not know the location of this kit on the AF330's.
- there are a great many other smaller parts, all of which seem to be the same honeycomb structure - no surprise, as such structures float...
From the available information (photos), these large, intact parts exhibit fracture, tear or blunt force patterns (including being struck by other parts as described earlier) but not large deformation patterns or a shattering into small fragments normally seen in a high-speed impact with water.
What the rest of the structure may exhibit is not yet known.
The information supplied by Great Bear is encouraging in the sense that loss of the CVR/DFDR signals may not end prospects for recovery. This still recognizes the significant task at hand and when/if discovered, the difficulties in recovery.
BTW, the galley, which photos showed up on the 17th with the skin-diver, was actually found on the 7th, as indicated by this PPRuNe posting:
Galley photo June 07
ClippedCub;
Thanks for your descriptions - I apologize for leaving my question and post open to interpretation regarding the suggestion of a "flat" spin - it wasn't yours I know but it has been made. I understand the dynamics of swept-wing flight and what happens in the stall/spiral/spin, (dynamic chord on the outside wing etc) but I wanted to understand how, and what the potential was, for a transport aircraft to enter/sustain a flat spin, where the nose is level or higher than the tail, given "normal" dynamics. In other words, with structural damage as per the BOAC 707 over Fuji which was a falling brick, all bets are off. To me, a steep nose-down attitude reaching very high speeds very swiftly and requiring great altitude to recover from, is far more likely an outcome from any non-recovered stall.
I'm using Davies' book but if you can point to other literature, I would be grateful.
PJ2
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Dorian B, the red dots are body recovery points? (I assume a dot could be more than one body at that location.)
Is there any list that matches the recovered items with the number shown for the item? And do you have any information on whether the numbered grey dots displayed are for the relatively larger sections of recovered wreckage?
Is there any list that matches the recovered items with the number shown for the item? And do you have any information on whether the numbered grey dots displayed are for the relatively larger sections of recovered wreckage?
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Dorian B, the red dots are body recovery points? (I assume a dot could be more than one body at that location.)
Is there any list that matches the recovered items with the number shown for the item? And do you have any information on whether the numbered grey dots displayed are for the relatively larger sections of recovered wreckage?
Is there any list that matches the recovered items with the number shown for the item? And do you have any information on whether the numbered grey dots displayed are for the relatively larger sections of recovered wreckage?
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numerical coincidence
99,9% probability of a meaningless relationship but who knows:
ISIS is linked to Adirus 1 and 3
IR2 (Adiru2 ?) was reported faulty by IR1 (ADIRU1) and IR3 (ADIRU3) (Is it true ?)
EFCS1 reported problems EFCS2 was having with pitot( - s ?) (Is it true ? Is EFCS2 linked to ADIRU2 ?)
ISIS has problems with gyroscope (comparison with ADIRUS 1 and 3?)
It is probably nonsense but I will post anyway.
ISIS is linked to Adirus 1 and 3
IR2 (Adiru2 ?) was reported faulty by IR1 (ADIRU1) and IR3 (ADIRU3) (Is it true ?)
EFCS1 reported problems EFCS2 was having with pitot( - s ?) (Is it true ? Is EFCS2 linked to ADIRU2 ?)
ISIS has problems with gyroscope (comparison with ADIRUS 1 and 3?)
It is probably nonsense but I will post anyway.
ttcse;
I was wondering about this as well - Davies discusses this at length in his section on stalls and super-stalls but the last (3rd, 1971) edition was more than thirty-five years ago; the design of wings and chord sections has changed dramatically since then and I would like very much to know what handling characteristics might be reasonably expected during the approach to stall and the stall itself and the characteristic of pitch-up as the stall moves inward from the tips and the center of lift moves forward.
This may be tech-forum stuff but it is a current topic here so once again I am seeking a contextual response rather than a non-related discussion on the stalling characteristics of modern transports.
While I understand that basic crude swept wings tend to tip-stall and subsequently the center-of-lift goes forward (enhancing the unhelpful nose-high attitude), are the swept wings of modern transports fairly immune from this with normal loading?
This may be tech-forum stuff but it is a current topic here so once again I am seeking a contextual response rather than a non-related discussion on the stalling characteristics of modern transports.
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aguadalte:
Quote:
Just a word to clarify that ISIS doesn't receive "attitude from internal gyros", it receives inputs from ADIRU1 and 3.
Captainflame:
My apologies, I may be wrong. (damn! I hate when I'm wrong
) And I hate (!) that "need to know - nice to know", Airbus philosophy 
)
Quote:
Just a word to clarify that ISIS doesn't receive "attitude from internal gyros", it receives inputs from ADIRU1 and 3.
The problem, as said earlier, is that ISIS containts are classified. I know it sounds weird but again, no one opens up this box !!
While it is true that it gets inputs from ADIRU 1 and 3, it is also true that it contains gyros !!
What inputs from ADIRUs ? I have no idea because the Airbus doumentation does not describe this. It could be to compare data, or to receive inputs from AOA and such....
It also is linked to ILS receiver 1 for example as you can display the LOC/GS sacles and diamonds.
As a matter of fact, ISIS needs to "align" its ATTitude on power up, and has an in flight ATT re-initialization button as well.
So the GYRO, Attitude information IS definitely self contained !
It is a BACKUP instrument. We know how to use it, we know what can go wrong with it, we do not know how it works inside !
Do we really need to ? not so sure.
By the way it is powered by BOTH the DC ESS bus and Hot Bus 1
While it is true that it gets inputs from ADIRU 1 and 3, it is also true that it contains gyros !!
What inputs from ADIRUs ? I have no idea because the Airbus doumentation does not describe this. It could be to compare data, or to receive inputs from AOA and such....
It also is linked to ILS receiver 1 for example as you can display the LOC/GS sacles and diamonds.
As a matter of fact, ISIS needs to "align" its ATTitude on power up, and has an in flight ATT re-initialization button as well.
So the GYRO, Attitude information IS definitely self contained !
It is a BACKUP instrument. We know how to use it, we know what can go wrong with it, we do not know how it works inside !
Do we really need to ? not so sure.
By the way it is powered by BOTH the DC ESS bus and Hot Bus 1
My apologies, I may be wrong. (damn! I hate when I'm wrong
) And I hate (!) that "need to know - nice to know", Airbus philosophy )