AF 447 Search to resume (part2)
takata, seems the general take on the evidence is that the FA were not seated. Given that some would have been resting, are you saying that there is no evidence one way or the other (for an unsecured cabin and FA not seated) in your opinion ?
Lemurian;
Thank you for calculating the probable crew relief times for the flight. Your numbers are what I would also have expected.
For further understanding I would like to comment/expand upon your points. My comments are in blue:
Lemurian wrote:
"Among the CRM / Human factors that the investigators are going to concentrate on, a few seem quite important :
- The accident happened very soon after the crew relief, at one of the worst times for vigilance..."
Could I ask you to clarify what you mean by "worst times for vigilance"? In my experience, crew-changeover time is (and should be) a routine matter providing thorough briefings are done. I'm interested in the point, especially as it has been placed under the notion of "human factors" - merci.
"- The AF procedures don't allow LHS qualifications for the F/Os."
Yes, understand - the procedures I am familiar with are the same, except perhaps that for the Relief Pilot position, AF uses First Officers who are licensed to sit in the RHS? Regardless, at some point, the F/Os doing the relief for one or the other two crew members will have to sit in the LHS but this would only be in cruise flight. By your statement I believe you mean that F/O's are not allowed to sit in the LHS for takeoff or landing, and that is the way I am familiar with. The Relief Pilot does not sit in either the LHS or RHS until the aircraft is in the Cruise phase of flight...that would be top-of-climb to top-of-descent.
"That means that the captain must be at his LHS for T/O and LDG. Which makes him take in 99% of the flights the middle slot."
No, not necessarily because crew breaks don't begin until reaching cruise, if I understood your note. In my experience, the RP almost always was given the first break and the landing pilot the last break, but that was just one of the more common ways of arranging breaks. Often I would take the middle break as it was the quietest in terms of cabin service and lighting but there was no real pattern. That said, in my view it would be a bit unusual for the captain to take the first break and I too believe he was on middle break.
"The fact that his body was recovered, and not the other two seem to confirm that fact."
Yes, I agree.
- In all certainty, the operation of this flight was performed by a senior F/O seating on the RHS with command functions and a junior F/O seating on the LHS with basic radio-com and navigation duties, along with some minor engineering duties.
Agree.
"IMVHO, we are very far from an optimum use of the flight deck crew's capability as the PF/PM duties are made difficult because of that task distribution : ECAM actions from the LHS are not that obvious and in many cases, there is a risk for the RHS pilot to lose his main flight instrument panels."
Agree. However, it works 99.9% of the time so the "approach to risk" is satisfied by the data. Whether it is justified is an entirely different question, and is the question which you have asked.
"- Still IMVHO, the risk of locking the captain out of the flight deck, for security reasons is immense. Maybe there's a way around it."
I believe the final descent would have been very turbulent, bordering on violent movements. Obtaining access to the flight deck would be near impossible if using the usual means, (staying away from describing).
Thanks again Lemurian.
Thank you for calculating the probable crew relief times for the flight. Your numbers are what I would also have expected.
For further understanding I would like to comment/expand upon your points. My comments are in blue:
Lemurian wrote:
"Among the CRM / Human factors that the investigators are going to concentrate on, a few seem quite important :
- The accident happened very soon after the crew relief, at one of the worst times for vigilance..."
Could I ask you to clarify what you mean by "worst times for vigilance"? In my experience, crew-changeover time is (and should be) a routine matter providing thorough briefings are done. I'm interested in the point, especially as it has been placed under the notion of "human factors" - merci.
"- The AF procedures don't allow LHS qualifications for the F/Os."
Yes, understand - the procedures I am familiar with are the same, except perhaps that for the Relief Pilot position, AF uses First Officers who are licensed to sit in the RHS? Regardless, at some point, the F/Os doing the relief for one or the other two crew members will have to sit in the LHS but this would only be in cruise flight. By your statement I believe you mean that F/O's are not allowed to sit in the LHS for takeoff or landing, and that is the way I am familiar with. The Relief Pilot does not sit in either the LHS or RHS until the aircraft is in the Cruise phase of flight...that would be top-of-climb to top-of-descent.
"That means that the captain must be at his LHS for T/O and LDG. Which makes him take in 99% of the flights the middle slot."
No, not necessarily because crew breaks don't begin until reaching cruise, if I understood your note. In my experience, the RP almost always was given the first break and the landing pilot the last break, but that was just one of the more common ways of arranging breaks. Often I would take the middle break as it was the quietest in terms of cabin service and lighting but there was no real pattern. That said, in my view it would be a bit unusual for the captain to take the first break and I too believe he was on middle break.
"The fact that his body was recovered, and not the other two seem to confirm that fact."
Yes, I agree.
- In all certainty, the operation of this flight was performed by a senior F/O seating on the RHS with command functions and a junior F/O seating on the LHS with basic radio-com and navigation duties, along with some minor engineering duties.
Agree.
"IMVHO, we are very far from an optimum use of the flight deck crew's capability as the PF/PM duties are made difficult because of that task distribution : ECAM actions from the LHS are not that obvious and in many cases, there is a risk for the RHS pilot to lose his main flight instrument panels."
Agree. However, it works 99.9% of the time so the "approach to risk" is satisfied by the data. Whether it is justified is an entirely different question, and is the question which you have asked.
"- Still IMVHO, the risk of locking the captain out of the flight deck, for security reasons is immense. Maybe there's a way around it."
I believe the final descent would have been very turbulent, bordering on violent movements. Obtaining access to the flight deck would be near impossible if using the usual means, (staying away from describing).
Thanks again Lemurian.
bear, not clear on the point. This was discussed a few hundred posts back (maybe last week ?). I understood there had been a tally of the recovered: does this align with the number you would expect to be resting: if more then that would point to active crew still in the cabin wouldn't it. Forgive me if I have the wrong end of this particular stick.
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Mr. Optiistic
The flight crew rest was discussed in the original thread, and concluded at the time that it was as PJ2 has just reiterated. FA break is undetermined. With nine, the logical conclusion is that one or two FAs were occupying the crew rest module at the upset. I do not remember if upon opening the box, that BEA discovered more victims. If it is disclosed, I missed it, and not the only thing I've missed, tbs.
The flight crew rest was discussed in the original thread, and concluded at the time that it was as PJ2 has just reiterated. FA break is undetermined. With nine, the logical conclusion is that one or two FAs were occupying the crew rest module at the upset. I do not remember if upon opening the box, that BEA discovered more victims. If it is disclosed, I missed it, and not the only thing I've missed, tbs.
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Originally Posted by Mr Optimistic
takata, seems the general take on the evidence is that the FA were not seated. Given that some would have been resting, are you saying that there is no evidence one way or the other (for an unsecured cabin and FA not seated) in your opinion
- fact #1: two FA seats were recovered floating and clearly unused.
- fact #2: there was 9 FAs on board, and the cabin passenger seats were fully occupied.
- fact #3: but there was a crew rest module (for FAs) and possibly three FAs service slots to be filled, like for the pilots.
The only evidence behind those three facts put together is that, at this stage of the flight, at least two (but possibly three) FAs were not seated in the cabin (resting in the module?), not that it was not secured!
On the other hand, some proof that the cabin was (well) secured should be left to the forensic analysis of the recovered bodies (which is not public so far).
CFIT
The term has been used several times of late. As this is (intended to be) a technical forum, I feel compelled to mention that there is no possibility that this accident could be / will be classified as a "CFIT" occurrence.
Rather than take up space in a thread not related to definitions of aviation terminology I shall simply say that if you are not convinced (as I'm sure the techical people here are) feel free to PM me -- after googling "CFIT".
The term has been used several times of late. As this is (intended to be) a technical forum, I feel compelled to mention that there is no possibility that this accident could be / will be classified as a "CFIT" occurrence.
Rather than take up space in a thread not related to definitions of aviation terminology I shall simply say that if you are not convinced (as I'm sure the techical people here are) feel free to PM me -- after googling "CFIT".
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I don't know the material, but the under counter stiffeners are completely untouched by the impact. Additionally, the food boxes were stowed, and undamaged. The one straddling the partitions I believe was placed there by the rescue diver.
Some help with the ACARS.?? The last "vertical speed" warning, it was determined it alerted because the a/c had passed cabin altitude at greater than 1800fpm ?? Meaning the cabin was not bleeding out with the drop in altitude ? The sensing is generic due three things yes?? descent, ascent, and depressurization?? If losing pressure, the cabin tells the computer it is "Ascending" correct?? Since ACARS is not a flight aspect warning system, but a maintenance tool to prioritize Mx at the landing, it is not going to report, "Depressurization, we'll need a new Aft Bulkhead at DeGaulle."
So ACARS could well have ended with the a/c at altitude, especially due upset and antenna issues. It is still a stretch for me to entertain antenna lock from 35k to 6kASL, plus the time it took to sense the difference?? It is more logical that ACARS quit at some great height, four minutes and some control into the upset phase...... If the a/c LOC at altitude, then is when I would think antenna was unlocked. So loss of some parts to me, is more than feasible.
It remains to be seen, but as I said, the evidence thus far is that the a/c CORE hit the water intact. A logical explanation has ensued, re: floaters, higher drift, etc. It seems presumptuous to eliminate another possibility out of hand. The other sections of fuselage?? Flaps?? HSs??
The lack of O2 masks, is that conclusive of intact, does it not exclude malfunction possibilities??
With a/p drop, is it in fact conclusive of UAS?? How about the a/p was overwhelmed, and the turbulence that did the whelming fubared the Pitots?? That is sufficient, given the conditions re Wx, No?? Mostly what I've read has to do with, "It cannot happen that way"....... Which I trust like I trust the USD....
Some help with the ACARS.?? The last "vertical speed" warning, it was determined it alerted because the a/c had passed cabin altitude at greater than 1800fpm ?? Meaning the cabin was not bleeding out with the drop in altitude ? The sensing is generic due three things yes?? descent, ascent, and depressurization?? If losing pressure, the cabin tells the computer it is "Ascending" correct?? Since ACARS is not a flight aspect warning system, but a maintenance tool to prioritize Mx at the landing, it is not going to report, "Depressurization, we'll need a new Aft Bulkhead at DeGaulle."
So ACARS could well have ended with the a/c at altitude, especially due upset and antenna issues. It is still a stretch for me to entertain antenna lock from 35k to 6kASL, plus the time it took to sense the difference?? It is more logical that ACARS quit at some great height, four minutes and some control into the upset phase...... If the a/c LOC at altitude, then is when I would think antenna was unlocked. So loss of some parts to me, is more than feasible.
It remains to be seen, but as I said, the evidence thus far is that the a/c CORE hit the water intact. A logical explanation has ensued, re: floaters, higher drift, etc. It seems presumptuous to eliminate another possibility out of hand. The other sections of fuselage?? Flaps?? HSs??
The lack of O2 masks, is that conclusive of intact, does it not exclude malfunction possibilities??
With a/p drop, is it in fact conclusive of UAS?? How about the a/p was overwhelmed, and the turbulence that did the whelming fubared the Pitots?? That is sufficient, given the conditions re Wx, No?? Mostly what I've read has to do with, "It cannot happen that way"....... Which I trust like I trust the USD....
I had post #37 in mind:
'It can take the CC a long time, from the receipt of a command to secure the cabin, to complete the task. The most compelling evidence I've seen that they had not completed that task was the excellent picture posted by Shadoko, here, of one of the galley catering-cannister stowage units. The latches that must be closed to secure the cannisters are plainly open. Any proximate cabin crew member worth his/her salt would have secured them before sitting down, if severe turbulence was expected. '
with apologies to CS.
'It can take the CC a long time, from the receipt of a command to secure the cabin, to complete the task. The most compelling evidence I've seen that they had not completed that task was the excellent picture posted by Shadoko, here, of one of the galley catering-cannister stowage units. The latches that must be closed to secure the cannisters are plainly open. Any proximate cabin crew member worth his/her salt would have secured them before sitting down, if severe turbulence was expected. '
with apologies to CS.
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I think Chris is referring to what I call "Flipper doors", the panels that keep the boxes inside the cabinet when closed, and open and then stow "inside" the partition on either side of the opening. This is to hide the doors out of the cabin space when open. It is a neat design, but requires very thin profile partitions to save weight. This is not a stout structure, by any means, especially when loose from the cabin superstructure. As difficult as others believe it is, that these cabinets were not in the a/c when it impacted, it is, in my professional opinion impossible they were present. I am leery of the size of the "Thrown Clear" file.........
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bearfoil Additionally, the food boxes were stowed, and undamaged. The one straddling the partitions I believe was placed there by the rescue diver.
http://cybermanin.eu/Blogs/Images/Ne...820_1_mini.jpg
and the box was on her place before.... with strait diagonale
http://cybermanin.eu/Blogs/Images/Ne...90820_mini.jpg
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rest periods
lemurian:
Am not familiar with AF traditions, but:
Disadvantage of dividing in 3 stretches is that 2 pilots end up with a long "sit" (6' 20" min). So at my airline it is usually divided in 6 stretches, ie in your example first 3x 1hr and then 3x 2hr10min. Enough left for a descent nap and enough rotations to stay awake upfront!
Ergo, hard to make conclusions who were in the cockpit.
- a T/O at 22:30 z
- a landing at 09:00 z
- The rest period of each pilot will be 10:30 - 1 = 9:30 : 3 = 3:10 hrs.
- They 'd then had crew changes at :
TOC + 3:10 = 23:00 z + 3:10 = 02:10 z : first crew change, and
02:10 z + 3:10 = 05:20 : second crew change.
- a landing at 09:00 z
- The rest period of each pilot will be 10:30 - 1 = 9:30 : 3 = 3:10 hrs.
- They 'd then had crew changes at :
TOC + 3:10 = 23:00 z + 3:10 = 02:10 z : first crew change, and
02:10 z + 3:10 = 05:20 : second crew change.
Disadvantage of dividing in 3 stretches is that 2 pilots end up with a long "sit" (6' 20" min). So at my airline it is usually divided in 6 stretches, ie in your example first 3x 1hr and then 3x 2hr10min. Enough left for a descent nap and enough rotations to stay awake upfront!
Ergo, hard to make conclusions who were in the cockpit.
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Originally Posted by Bearfoil
takata
"- fact #3: but there was a crew rest module (for FAs) and possibly three FAs service slots to be filled, like for the pilots."
I think full complement of FAs on duty is six, three resting.
"- fact #3: but there was a crew rest module (for FAs) and possibly three FAs service slots to be filled, like for the pilots."
I think full complement of FAs on duty is six, three resting.
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The Importance of Timely Control Input
The following discussion will not be able to reach to everyone here because of differing areas of experience, but to those who understand, it will help make the point-Timeliness is everything in control input, particularly when you are attempting to stabilize an unstable situation.
How many of you have flown tail draggers? Of those, how many have performed wheel landings? (I know of a couple of guys who pass the first criterea but not the second.) If you qualify for the second criterea, read on.
During a wheel landing the aircraft is (generally) flown down to the runway in a level attitude and the wheels are placed gently on the runway which if you are skillful will cause a slight pitch down as the momentum used in spinning up the wheels acts upon a point below the CG and creates a brief nose down pitch. This slight pitch down will help hold the aircraft on the runway and the aircraft can then be decelerated and transitioned to 3 point landing attitude. (Remember that tail draggers have the main landing gear positioned ahead of the CG)
If you reach the surface a little more firmly, the landing can be saved by a small amount of nose down input, but that nose down input must be timely. If you are half a second late, the aircraft will have skipped back into the air and your nose down input will create a second slightly more firm touchdown. If your response is again late, the result is a rapidly escalating series of bounces that would make a Kangaroo jealous.
At that point you must go around or crash.
A similar process is also at work on MD-11 landing accidents although there are many more factors causing the effect.
So what is the relevance to an Airbus flight control system? Simple. Timeliness is everything. When the aircraft's CG is aft, inherent pitch and yaw damping are reduced. Inherent stability is reduced. The aircraft gets its nice flying characteristics by virtue of timely computer directed control inputs. Let those control inputs be delayed and Katy bar the door.
Discussion?
How many of you have flown tail draggers? Of those, how many have performed wheel landings? (I know of a couple of guys who pass the first criterea but not the second.) If you qualify for the second criterea, read on.
During a wheel landing the aircraft is (generally) flown down to the runway in a level attitude and the wheels are placed gently on the runway which if you are skillful will cause a slight pitch down as the momentum used in spinning up the wheels acts upon a point below the CG and creates a brief nose down pitch. This slight pitch down will help hold the aircraft on the runway and the aircraft can then be decelerated and transitioned to 3 point landing attitude. (Remember that tail draggers have the main landing gear positioned ahead of the CG)
If you reach the surface a little more firmly, the landing can be saved by a small amount of nose down input, but that nose down input must be timely. If you are half a second late, the aircraft will have skipped back into the air and your nose down input will create a second slightly more firm touchdown. If your response is again late, the result is a rapidly escalating series of bounces that would make a Kangaroo jealous.
At that point you must go around or crash.
A similar process is also at work on MD-11 landing accidents although there are many more factors causing the effect.
So what is the relevance to an Airbus flight control system? Simple. Timeliness is everything. When the aircraft's CG is aft, inherent pitch and yaw damping are reduced. Inherent stability is reduced. The aircraft gets its nice flying characteristics by virtue of timely computer directed control inputs. Let those control inputs be delayed and Katy bar the door.
Discussion?
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Pitots and UAS events
Hi,
Originally posted by sensor_validation (#1385)
I wouldnīt like to design one with much more than this ~12+ Amps. A temp. feedback is easy to implement and has benefits.
We donīt know if this parameter is used for the pwr modulation.
n/c
Typical pwr modulation steps could be:
1) "Idle" (your 60 deg)
2) Normal, letīs say the current max power used today (approx. 300W)
3) Max, when a temp. sensor (TAT?) "inform" itīs required or JUST AFTER UAS is detected. (feedback from temp. sensor return pwr to Normal step)
4) A manual mode (time limited) for Max activation (feedback from temp. sensor return pwr to Normal step)
Note. This approach TOGETHER the "use of IR data" during short term (detected) UAS could IMHO reduce the UAS cases (water, ice, etc. related)
I am assuming the UAS cases could be less frequent using higher power.
How much more? But this requires replacement by new Pitots with Max pwr handling capability. Or even with pressure transducer separated.
Obs. The use of higher voltage: 115V in order (if heater MTBF is preserved) to apply more than 28V (by transformer) or by "inverting" 28V to letīs say, 50% could led to the use "the same" Pitots. Commenting on that iīm just "optimizing" overall costs. But this is questionable by many reasons.
The other option is to use the Laser "pitots" when (if ever) available.
A Patent filed by EADS less than 6 months after loss of AF447.
Originally posted by sensor_validation (#1385)
The A300 FCOM mentions 28VDC and 320W, but the actual power deliverable will not be constant.
The probe heaters are made out of resistance wire, the actual resistance changes with temperature, so monitoring the current gives an indication of the heater coil temperature.
In other applications such as process industries handling flammable materials self limiting heat tracing tapes are used exploiting this effect.
For what power - consider a bench soldering iron - 12W can be used without any control to limit tip to about 200degC. 60W irons need temperature control - can only use higher power when soldering big things. Instant heat guns 100W will heat tip to red-heat in a few seconds. I'm sure you don't want the pitot tube more than 60degC on the ground, but its very important that you can check the heating - design case for heating and drain holes will be take-off clinb in bad weather.
1) "Idle" (your 60 deg)
2) Normal, letīs say the current max power used today (approx. 300W)
3) Max, when a temp. sensor (TAT?) "inform" itīs required or JUST AFTER UAS is detected. (feedback from temp. sensor return pwr to Normal step)
4) A manual mode (time limited) for Max activation (feedback from temp. sensor return pwr to Normal step)
Note. This approach TOGETHER the "use of IR data" during short term (detected) UAS could IMHO reduce the UAS cases (water, ice, etc. related)
I am assuming the UAS cases could be less frequent using higher power.
How much more? But this requires replacement by new Pitots with Max pwr handling capability. Or even with pressure transducer separated.
Obs. The use of higher voltage: 115V in order (if heater MTBF is preserved) to apply more than 28V (by transformer) or by "inverting" 28V to letīs say, 50% could led to the use "the same" Pitots. Commenting on that iīm just "optimizing" overall costs. But this is questionable by many reasons.
The other option is to use the Laser "pitots" when (if ever) available.
A Patent filed by EADS less than 6 months after loss of AF447.
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Quote by Bearfoil:
On Pg. 39, BEA Interim Report #1, there is a photo of a galley storage unit. Externals look in relatively good shape, basket and racks found compressed at the bottom. This is the center G2 galley, located in the middle of the first/business class, at the second exit doors location. So it survived the vertical impact. Now the other galley depicted in grity's post is not clear in my mind as to location, but guessing near the rear of the plane?
Although they don't seem stout in construction, they seemingly survive rather well. I wonder if what is beneath these galleys play a role in their survival. Could it be LD-3 containers present or no LD-3 containers (air) that plays a role on a high speed but generally flat vertical descent?
This is not a stout structure, by any means, especially when loose from the cabin superstructure. As difficult as others believe it is, that these cabinets were not in the a/c when it impacted, it is, in my professional opinion impossible they were present. I am leery of the size of the "Thrown Clear" file.........
Although they don't seem stout in construction, they seemingly survive rather well. I wonder if what is beneath these galleys play a role in their survival. Could it be LD-3 containers present or no LD-3 containers (air) that plays a role on a high speed but generally flat vertical descent?
Last edited by Jetdriver; 16th May 2011 at 11:30.