AF 447 Search to resume
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My last post mentions nothing of any disintegration or even a dropped gerkin fork.
It could easily have ended as BEA would have it. Without questions, the temptation is to let others think for us. As you say, BEA makes no conclusions. why not challenge each other with possibilities. I know, wait for the final report.
I'm going Phishing, Phor Phlounder.
bear
My last post mentions nothing of any disintegration or even a dropped gerkin fork.
It could easily have ended as BEA would have it. Without questions, the temptation is to let others think for us. As you say, BEA makes no conclusions. why not challenge each other with possibilities. I know, wait for the final report.
I'm going Phishing, Phor Phlounder.
bear
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Stall Warning
I wonder, did they mention stall warning, and why it was ignored?
HN39
HN39
If so, the pitot tubes were already declared unreliable.
With the computers deciding the pitot tubes were malfunctioning (unreliable air-speed)
would they immediately trigger as stall warn just in case, or suppress the stall warning because they're 'not sure'?
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Stall Warning
TiberiusKirk;
I was asking about the content of a BBC program that I was unable to see.
From BEA's 2nd report:
The angle of attack is obtained from AoA vanes located on the nose of the airplane.
HN39
I was asking about the content of a BBC program that I was unable to see.
Originally Posted by TiberiusKirk
What generates a stall warning? Is it low air-speed detected?
In alternate or direct law, the angle-of-attack protections are no longer available but a stall warning is triggered when the greatest of the valid angle-of-attack values exceeds a certain threshold. In clean configuration, this threshold depends, in particular, on the Mach value in such a way that it decreases when the Mach increases. It is the highest of the valid Mach values that is used to determine the threshold. If none of the three Mach values is valid, a Mach value close to zero is used. For example, it is of the order of 10° at Mach 0.3 and of 4° at Mach 0.8.
HN39
Last edited by HazelNuts39; 31st May 2010 at 23:26. Reason: vanes
I would hazard a guess that the stall protection will be based on alpha provided by the AoA vanes to the Adirs.The QRH states that with a triple ADIRS failure stall warning is lost.The QRH continues by requiring use of the standby altimeter/ASI but if these are unreliable as well you are rapidly into unreliable airspeed territory which the x-list fails to mention!This x-list does appear next in the QRH.
The x-list for unreliable airspeed is quite long and initially requires a number of memory items.Pitch and power settings for level flight do not appear until the fourth page.
Did anybody else notice the sim in the BBC programme was an A320?
The x-list for unreliable airspeed is quite long and initially requires a number of memory items.Pitch and power settings for level flight do not appear until the fourth page.
Did anybody else notice the sim in the BBC programme was an A320?
Last edited by tubby linton; 31st May 2010 at 23:43.
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tubby linton;
Which explains why they stated the turbulence penetration speed was M0.78 instead of M0.80 in the A330.
mm43
Did anybody else notice the sim in the BBC programme was an A320?
mm43
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Originally Posted by Wilyflier
Can any one equate the design strength of the VS with the max possible deceleration "G" in any sort of flat ditching, and the forward "G" required to permit a fin and rudder to rip clean off its fittings?
I have no idea though, what decel 'g' in a flat ditching situation would fail the fin as suggested by the BEA report... other than more than 3g
Last edited by HarryMann; 1st Jun 2010 at 00:44. Reason: change quote author
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No mention of stall warning specifically. I can imagine it would be quite easy to ignore stall warning if you already believe the plane doesn't have a clue how fast it's going anymore.
The BBC had limited time, to go into everything, particularly when trying to get in as much dramatic commentary as possible...
They may well have filmed discussion on stall warning and then cut it.There was very little on the VS also - basically taken as read the BEA conclusion that it was still attached at impact. There's probably enough material on the VS on this thread to make an hours television just on that subject - however the interested audience would then be a bit more limited!
Not a bad program at all (certainly not full of hype or innaccuracies), but equally it doesn't bring anything new if you've already read this thread (for instance).
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ACARS transmitted
Hello mm43,
Right, I have seen this but it is a different matter that considering that other ACARS messages were actually sent and not received.
All cases discussed above are linked to ACARS sequences interrupted which relevant part missing were actually NOT sent by the systems but which fault msg had not reached their time limit before being possibly triggered. On the other hand, Hydraulics faults messages are completely missing and it is consequently possible to point out that no hydraulic fault occured between 02.10 and ~02.14. If one hydraulic fault ever occured without being tansmitted, it would be at the very very end when ACARS were shut down.
Then, if one want to explain an upset between 02.10-02.14 with problems triggering hydraulic faults, he should be able to explain why it would take 4, 3, 2 or 1 minute for such an ACARS to be sent and to verify if such a case is possible, which is not.
My point was that investigation pointed that all ACARS sent by AF447 were received. There was no imaginatory sent ACARS missing as Bearfoil was suggesting and possible delays for such hard fault are only in the order of few seconds.
S~
Olivier
Originally Posted by mm43
In a reply to Bearfoil you wrote:- Quote:
I never read something about that. Reports are saying that all ACARS transmitted by AF447 were received.
I think that Bear is referring to the following detail from page 36 (English version) of the BEA Interim Report No.2. The PRIM 1 and SEC 1 faults below are possibilities, but the MAINTENANCE STATUS ADR2 would have been sent (if possible to do so).
F/CTL PRIM 1 FAULT (2 h 13)
This message indicates that FCPC1 (PRIM 1) has stopped functioning. This shutdown may have been commanded or be the result of a failure. In the absence of an associated fault message, it is not possible to command a shutdown. However, a fault message that had not had sufficient time to be transmitted can not be excluded. Indeed, this message was received at 2 h 13 min 45 and the last message at 2 h 14 min 26, whereas the fault message could have appeared up until 2 h 14 min 45.
F/CTL SEC 1 FAULT (2 h 13)
This message indicates that FCSC1 (SEC 1) has stopped functioning. This shutdown may have been commanded or be the result of a failure. In the absence of an associated fault message, it is not possible to command a shutdown. However, a fault message that had not had sufficient time to be transmitted can not be excluded. Indeed, this message was received at2 h 13 min 51 and the last message at 2 h 14 min 26, whereas the fault message could have appeared up until 2 h 14 min 51.
MAINTENANCE STATUS ADR2 (2 h 14)
This message was received at 2 h 14 min 14 and a class 2 fault message should have been received between 2 h 15 min 00 and 2 h 15 min 14.
I never read something about that. Reports are saying that all ACARS transmitted by AF447 were received.
I think that Bear is referring to the following detail from page 36 (English version) of the BEA Interim Report No.2. The PRIM 1 and SEC 1 faults below are possibilities, but the MAINTENANCE STATUS ADR2 would have been sent (if possible to do so).
F/CTL PRIM 1 FAULT (2 h 13)
This message indicates that FCPC1 (PRIM 1) has stopped functioning. This shutdown may have been commanded or be the result of a failure. In the absence of an associated fault message, it is not possible to command a shutdown. However, a fault message that had not had sufficient time to be transmitted can not be excluded. Indeed, this message was received at 2 h 13 min 45 and the last message at 2 h 14 min 26, whereas the fault message could have appeared up until 2 h 14 min 45.
F/CTL SEC 1 FAULT (2 h 13)
This message indicates that FCSC1 (SEC 1) has stopped functioning. This shutdown may have been commanded or be the result of a failure. In the absence of an associated fault message, it is not possible to command a shutdown. However, a fault message that had not had sufficient time to be transmitted can not be excluded. Indeed, this message was received at2 h 13 min 51 and the last message at 2 h 14 min 26, whereas the fault message could have appeared up until 2 h 14 min 51.
MAINTENANCE STATUS ADR2 (2 h 14)
This message was received at 2 h 14 min 14 and a class 2 fault message should have been received between 2 h 15 min 00 and 2 h 15 min 14.
All cases discussed above are linked to ACARS sequences interrupted which relevant part missing were actually NOT sent by the systems but which fault msg had not reached their time limit before being possibly triggered. On the other hand, Hydraulics faults messages are completely missing and it is consequently possible to point out that no hydraulic fault occured between 02.10 and ~02.14. If one hydraulic fault ever occured without being tansmitted, it would be at the very very end when ACARS were shut down.
Then, if one want to explain an upset between 02.10-02.14 with problems triggering hydraulic faults, he should be able to explain why it would take 4, 3, 2 or 1 minute for such an ACARS to be sent and to verify if such a case is possible, which is not.
My point was that investigation pointed that all ACARS sent by AF447 were received. There was no imaginatory sent ACARS missing as Bearfoil was suggesting and possible delays for such hard fault are only in the order of few seconds.
S~
Olivier
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Icing conditions
Originally Posted by Loose rivets;#1306
The program gave a mini-course on supercooled water and pitot heads, but said little or nothing about airframe icing while encountering the phenomenon.
Severe icing from supercooled droplets can be astonishingly sudden, and flying an aircraft in turbulence, with the added burden of ice, could be one reason the crew had difficulty in staying inside the envelope.
Severe icing from supercooled droplets can be astonishingly sudden, and flying an aircraft in turbulence, with the added burden of ice, could be one reason the crew had difficulty in staying inside the envelope.
... the presence of super cooled water at FL350 is not very probable and would necessarily have been limited to small quantities.
It seems that the relatively recent icing problem at high altitudes with pitots (and perhaps also engines) is not caused by liquid water but by fine ice particles which present no particular problem for the airframe. From BEA report no.2:
Examination of reported UAS events in cruise has shown that the majority of them occurred outside of the envelope defined in Appendix C. In fact, the certification criteria are not representative of the conditions that are really encountered at high altitude, for example with regard to temperatures. In addition, it appears that some elements, such as the size of the ice crystals within cloud masses, are little known and that it is consequently difficult to evaluate the effect that they may have on some equipment, in particular the Pitot probes. In this context, the tests aimed at the validation of this equipment do not appear to be well-adapted to flights at high altitude.
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BBC Video
Although I am a hard defender of the need for commercial pilots to keep proficient and skilled in manual flying, it was sad to see that the "investigators" and "experts" interviewed by BBC, have passed to the general public, the idea that the Air France pilots were unable to recover from stall, because they were not trained (and not used to fly manually)...
To compare the ability of that military pilot, to recover from stall, without mentioning that there was a huge difference between doing it in a flight simulator, with available speed information, and trying to recover a stalled heavy bird without speed info, is intellectually dishonest.
That colonel has lost almost half of his altitude to recover from stall. I'd love to see him talking, after a couple of attempts in a heavy jet, with almost 5 tons of fuel in the trim tank and without proper speed read-outs, in turbulence and dark...
To compare the ability of that military pilot, to recover from stall, without mentioning that there was a huge difference between doing it in a flight simulator, with available speed information, and trying to recover a stalled heavy bird without speed info, is intellectually dishonest.
That colonel has lost almost half of his altitude to recover from stall. I'd love to see him talking, after a couple of attempts in a heavy jet, with almost 5 tons of fuel in the trim tank and without proper speed read-outs, in turbulence and dark...
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Humble SLF question here.
It's been suggested that digital displays are hard to read if everything is vibrating in extreme turbulence. If the conditions are that rough, how easy is it to actually get your fingers onto a button or dial to change settings?
Is it easier to have throttles to physically hold onto while you're trying to change engine settings, than tweak a smallish dial?
If these are dumb questions, I apologise. I'm just wondering if this kind of situation has been factored into Airbus design?
It's been suggested that digital displays are hard to read if everything is vibrating in extreme turbulence. If the conditions are that rough, how easy is it to actually get your fingers onto a button or dial to change settings?
Is it easier to have throttles to physically hold onto while you're trying to change engine settings, than tweak a smallish dial?
If these are dumb questions, I apologise. I'm just wondering if this kind of situation has been factored into Airbus design?
overthewing,
I think you have already guessed the correct answer.
Other than a short play in the simulator, I haven't flown the 'Bus but with Boeings, one would also normally make selections via the Mode Control Panel or Flight Management System keyboard.
In moderate turbulence, on occasion, I've had to use both hands to make selections, one to steady the other.
Turbulence also makes instrument interpretation a little more difficult.
IF those guys flew into a Cb then, clearly, things would be a deal worse than I've described.
Over my aviation career, even mechanical instruments became smaller in order to fit more onto a finite panel space. If I had to make a choice between 1980s mechanical instruments and a glass cockpit, I'd have to say that maintaining situational awareness is much easier with glass.
Perhaps someone with a few thousand hours on each of Airbus and Boeing could comment further. (or give the posting number if it's been mentioned already
)
I think you have already guessed the correct answer.
Other than a short play in the simulator, I haven't flown the 'Bus but with Boeings, one would also normally make selections via the Mode Control Panel or Flight Management System keyboard.
In moderate turbulence, on occasion, I've had to use both hands to make selections, one to steady the other.
Turbulence also makes instrument interpretation a little more difficult.
IF those guys flew into a Cb then, clearly, things would be a deal worse than I've described.
Over my aviation career, even mechanical instruments became smaller in order to fit more onto a finite panel space. If I had to make a choice between 1980s mechanical instruments and a glass cockpit, I'd have to say that maintaining situational awareness is much easier with glass.
Perhaps someone with a few thousand hours on each of Airbus and Boeing could comment further. (or give the posting number if it's been mentioned already
)
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FBW. It is not "state of the art", it is old. Likewise, it is dependable. No authority would allow skimping on Stall Recovery training without unquestionable confidence in it. When I fly, I yank the straps tight, just short of pain. As a student, a defective seat rail slid me back full on take off. Luckily I am tall, and didn't need to squirm forward while flying solo at launch.
Throttle manipulation? Panel reads? Bouncing about when called upon to start reading a book through page four to find out life saving instructions isn't old, it is stupid. Likewise, when a specific throttle position is do or die, and you can't scratch your ass let alone smoothly caress the power, something is terribly wrong.
Look for Voice recognition commands to the controls in the future.
ACARS is a maintenance option, something to cut the costs for big carriers. It is not intended to substitute for FDR. It logs and sends information so the Mx crew at the next shop can prioritize their work and have a lead on important parts. Just because a message wasn't received certainly does not mean it was not sent. It takes the pilots out of the Mx equation as well, someone whose input will be included at the next stop.
I think the VS failed laterally while in flight, as a result of the fractures seen in the mountings in BEA's photography. This does NOT mean a failure of hydraulics, necessarily. My estimate of the lateral play in this control is 1-2 feet at the tip, post fracture. Obviously, if the VS failed flat (the photography does not show this), it would have been lost. So the cracks in the female bracket (tower) allow dangerous play, but suggest no loss (departure) of the VS/Rudder in flight. Some combination of lateral rods, remaining integrity of the lugs, and lack of overwhelming deflection argue that the VS was hobbled, not missing. At impact? Severely compromised lateral strength and a weakened bed may not have required much more than 2-3 g's for forward separation at water entry, (impact). A sharp pilot might read lack of crisp yaw control as a breaking or broken Stabilizer or Rudder, and laid off, or tried spoilers? Perhaps asym thrust for yaw control? Or was it RTLU at ~8 +/- ?
bear
Throttle manipulation? Panel reads? Bouncing about when called upon to start reading a book through page four to find out life saving instructions isn't old, it is stupid. Likewise, when a specific throttle position is do or die, and you can't scratch your ass let alone smoothly caress the power, something is terribly wrong.
Look for Voice recognition commands to the controls in the future.
ACARS is a maintenance option, something to cut the costs for big carriers. It is not intended to substitute for FDR. It logs and sends information so the Mx crew at the next shop can prioritize their work and have a lead on important parts. Just because a message wasn't received certainly does not mean it was not sent. It takes the pilots out of the Mx equation as well, someone whose input will be included at the next stop.
I think the VS failed laterally while in flight, as a result of the fractures seen in the mountings in BEA's photography. This does NOT mean a failure of hydraulics, necessarily. My estimate of the lateral play in this control is 1-2 feet at the tip, post fracture. Obviously, if the VS failed flat (the photography does not show this), it would have been lost. So the cracks in the female bracket (tower) allow dangerous play, but suggest no loss (departure) of the VS/Rudder in flight. Some combination of lateral rods, remaining integrity of the lugs, and lack of overwhelming deflection argue that the VS was hobbled, not missing. At impact? Severely compromised lateral strength and a weakened bed may not have required much more than 2-3 g's for forward separation at water entry, (impact). A sharp pilot might read lack of crisp yaw control as a breaking or broken Stabilizer or Rudder, and laid off, or tried spoilers? Perhaps asym thrust for yaw control? Or was it RTLU at ~8 +/- ?
bear
Last edited by bearfoil; 1st Jun 2010 at 20:15.
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