AF 447 Thread No. 9
Lack of overspeed warning
Salute!
Good grief, Doze, how ya gonna get an overspeed warning if the air data system is FUBAR?
So maybe the junior crewmember up front was more worried about overspeed than stall or something else. And I have a problem with the senior guy in the other seat not "suggesting" something early in the UAS.
The simple fact is that we here shall never know until we meet those dudes in that neat hootch bar in the sky and get their side of the story.
That's what Gums says this nice evening in the high country...
Good grief, Doze, how ya gonna get an overspeed warning if the air data system is FUBAR?
So maybe the junior crewmember up front was more worried about overspeed than stall or something else. And I have a problem with the senior guy in the other seat not "suggesting" something early in the UAS.
The simple fact is that we here shall never know until we meet those dudes in that neat hootch bar in the sky and get their side of the story.
That's what Gums says this nice evening in the high country...
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@gums:
The speeds had in fact been back online for almost a minute prior to the "crazy speed" comment. Just before the comment was made, the air data was again fouled, this time by stalled air.
The reason I can't fathom why he'd think "overspeed" is that the aircraft had been descending increasingly rapidly with the nose consistently pitched above neutral for 45 seconds prior to the comment - this behaviour is completely inconsistent with overspeed.
The speeds had in fact been back online for almost a minute prior to the "crazy speed" comment. Just before the comment was made, the air data was again fouled, this time by stalled air.
The reason I can't fathom why he'd think "overspeed" is that the aircraft had been descending increasingly rapidly with the nose consistently pitched above neutral for 45 seconds prior to the comment - this behaviour is completely inconsistent with overspeed.
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@bubbers44:
Experience is certainly a factor, but there are other more complex issues involved.
The PNF didn't actually have a great deal more hours under his belt than the PF, but it seems apparent that he had a better handle on the situation at first. Regardless of experience, some people handle pressure and abnormal situations better than others - and the initial difference in approach between the two FOs seems to highlight this.
What's more disturbing is the complete lack of CRM throughout the sequence and the fact that upon his arrival, the Captain got bogged down in a reactive mode rather than taking charge and pooling all the information as to what happened before his arrival.
Experience is certainly a factor, but there are other more complex issues involved.
The PNF didn't actually have a great deal more hours under his belt than the PF, but it seems apparent that he had a better handle on the situation at first. Regardless of experience, some people handle pressure and abnormal situations better than others - and the initial difference in approach between the two FOs seems to highlight this.
What's more disturbing is the complete lack of CRM throughout the sequence and the fact that upon his arrival, the Captain got bogged down in a reactive mode rather than taking charge and pooling all the information as to what happened before his arrival.
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Hi,
DW:
Just five times more ....
1.5.1.2 Co-pilot in left seat (Robert)
Male, aged 37
ˆ Medical certificate (class 1) issued 11 December 2008, valid until 3
2009 with compulsory wearing of corrective lenses.
ˆ Experience:
y total: 6,547 flying hours
y on type: 4,479 flying hours
y in the previous six months: 204 hours, 9 landings, 11 take-offs
y in the previous three months: 99 hours, 6 landings, 5 take-offs
y in the previous thirty days: 39 hours, 2 landings, 2 take-offs
1.5.1.3 Copilot in right seat (Bonin)
Male, aged 32
ˆ Medical certificate (class 1) issued on 24 October 2008, valid until 31 Oc
2009 with compulsory wearing of corrective lenses.
ˆ Experience:
y total: 2,936 flying hours
y on type: 807 flying hours
y in the previous six months: 368 hours, 16 landings, 18 take-offs
y in the previous three months: 191 hours, 7 landings, 8 take-offs
y in the previous thirty days: 61 hours, 1 landing, 2 take-offs
DW:
The PNF didn't actually have a great deal more hours under his belt than the PF, but
1.5.1.2 Co-pilot in left seat (Robert)
Male, aged 37
ˆ Medical certificate (class 1) issued 11 December 2008, valid until 3
2009 with compulsory wearing of corrective lenses.
ˆ Experience:
y total: 6,547 flying hours
y on type: 4,479 flying hours
y in the previous six months: 204 hours, 9 landings, 11 take-offs
y in the previous three months: 99 hours, 6 landings, 5 take-offs
y in the previous thirty days: 39 hours, 2 landings, 2 take-offs
1.5.1.3 Copilot in right seat (Bonin)
Male, aged 32
ˆ Medical certificate (class 1) issued on 24 October 2008, valid until 31 Oc
2009 with compulsory wearing of corrective lenses.
ˆ Experience:
y total: 2,936 flying hours
y on type: 807 flying hours
y in the previous six months: 368 hours, 16 landings, 18 take-offs
y in the previous three months: 191 hours, 7 landings, 8 take-offs
y in the previous thirty days: 61 hours, 1 landing, 2 take-offs
Last edited by jcjeant; 16th Jul 2012 at 01:58.
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Originally Posted by Dozy
The reason I can't fathom why he'd think "overspeed" is that the aircraft had been descending increasingly rapidly with the nose consistently pitched above neutral for 45 seconds prior to the comment - this behaviour is completely inconsistent with overspeed.
In any case, it is tragic that the lack of deceleration when he briefly deployed the speedbrakes didn't start someone thinking. Instead the lightning bolts sparking between the PM and PF by then washed away the ability to form that type of question.
Incidentally, has anyone considered the short period that PM was awake as a potential reason for his lack of assertiveness. Perhaps he just didn't trust himself yet?
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Originally Posted by DozyWannabe
At any rate, the point I was trying to make was that in modern airliners, yokes aren't simply attached to a big metal bar like they were in the days of yore, they are complex electro-mechanical devices that can behave in unexpected ways when put into unusual configurations.
And I should clarify that my point was only that the Airbus dual-input logic makes sense when one thinks about it and probably wasn't designed by "idiots".
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As to why the PM/PNF was not more assertive; after he told the PF to be more gentle with SS movements while PF was “stirring mayonnaise” (and PF had taken back control when PNF had started to correct the nose up condition), PNF concentrated on calling back the CDB. It seemed to me that the way CDB had handed control to PF before he left the cockpit may have implied that PF was not only PF but acting PIC too.
This would explain (not justify, but explain) both why PF felt he could seize control back from PNF, and why PNF then gave up trying to override PF and instead wanted the CDB back to assert his authority.
Admitted speculation, but it fits who did what.
(I tried to find the CVR transcript again but can’t – but I did read some of it that reached the public, which had that implication as i read it.)
This would explain (not justify, but explain) both why PF felt he could seize control back from PNF, and why PNF then gave up trying to override PF and instead wanted the CDB back to assert his authority.
Admitted speculation, but it fits who did what.
(I tried to find the CVR transcript again but can’t – but I did read some of it that reached the public, which had that implication as i read it.)
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@DL-EDI...
"And I should clarify that my point was only that the Airbus dual-input logic makes sense when one thinks about it and probably wasn't designed by "idiots"."
Howdy. Yes, the solution is elegant. My point went to the actual need for a solution in the first place. In creating a system that facilitates inadvertent dual input, the solution becomes mandatory. The argument against dual yoke seemed to be based on physical confrontation, a separate issue. At no time did I imply that The Airbus system was vulnerable to battling pilots. On the contrary, the danger is in the subtlety of the SS, and it's other shortcomings, visibility being one, and I'll add lack of shaker warn to that. BEA have demonstrated that in Alternate Law, the Airbus is mostly vanilla, but untested in STALL, so the basis for a stick (shaker) waiver is found to be awarded in error.
Clandestino has posited, in my opinion, that a shaker is not needed, simply because it is not fitted ...
The CVR has been removed from the report, at least in my efforts, I cannot find it. I was trying to locate the new to the discussion remark made by CDB DuBois to the effect that the selector had remained in "ON". That is my conclusion, or that he had attempted to select it "ON" for some reason. The CVR remark was not clear, only that the sound of a selector being cycled was picked up by the Cockpit Area Microphone....
"And I should clarify that my point was only that the Airbus dual-input logic makes sense when one thinks about it and probably wasn't designed by "idiots"."
Howdy. Yes, the solution is elegant. My point went to the actual need for a solution in the first place. In creating a system that facilitates inadvertent dual input, the solution becomes mandatory. The argument against dual yoke seemed to be based on physical confrontation, a separate issue. At no time did I imply that The Airbus system was vulnerable to battling pilots. On the contrary, the danger is in the subtlety of the SS, and it's other shortcomings, visibility being one, and I'll add lack of shaker warn to that. BEA have demonstrated that in Alternate Law, the Airbus is mostly vanilla, but untested in STALL, so the basis for a stick (shaker) waiver is found to be awarded in error.
Clandestino has posited, in my opinion, that a shaker is not needed, simply because it is not fitted ...
The CVR has been removed from the report, at least in my efforts, I cannot find it. I was trying to locate the new to the discussion remark made by CDB DuBois to the effect that the selector had remained in "ON". That is my conclusion, or that he had attempted to select it "ON" for some reason. The CVR remark was not clear, only that the sound of a selector being cycled was picked up by the Cockpit Area Microphone....
Last edited by Lyman; 16th Jul 2012 at 12:26.
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I haven't seen actual audio file, anywhere.
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Thanks, that is working
2:13:53. From Captain. "(so wait) AP OFF". Sound of selector.....
Whether or not the a/p was engaged, apparently, the selector was ON. Seems a poor result that may upset or interrupt, or lengthen, the attempt to recover flight path.
If the crew rejected STALL from the very first chirp, the campaign against it for the rest of the descent makes sense, the WARNING was actively ignored. IS there no CB to eliminate the perceived distraction? Why carry on listening to something deemed an enemy of recovery?
Is there a linked circuit that shows a conflict in the a/p channel? Because as important as the system is, it would seem imperative to extinguish a false
display...is this in the report?
Not one mention of the STALL WARN by anyone of the three? Challenges credulity.
Jcjeant, you follow the trial? Has anyone formally challenged the BEA to supply the full CVR, with audio? Seems an obvious course of action, the part released to the public challenges common sense, not to mention airmanship...
2:13:53. From Captain. "(so wait) AP OFF". Sound of selector.....
Whether or not the a/p was engaged, apparently, the selector was ON. Seems a poor result that may upset or interrupt, or lengthen, the attempt to recover flight path.
If the crew rejected STALL from the very first chirp, the campaign against it for the rest of the descent makes sense, the WARNING was actively ignored. IS there no CB to eliminate the perceived distraction? Why carry on listening to something deemed an enemy of recovery?
Is there a linked circuit that shows a conflict in the a/p channel? Because as important as the system is, it would seem imperative to extinguish a false
display...is this in the report?
Not one mention of the STALL WARN by anyone of the three? Challenges credulity.
Jcjeant, you follow the trial? Has anyone formally challenged the BEA to supply the full CVR, with audio? Seems an obvious course of action, the part released to the public challenges common sense, not to mention airmanship...
Last edited by Lyman; 16th Jul 2012 at 13:21.
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Jcjeant, you follow the trial? Has anyone formally challenged the BEA to supply the full CVR, with audio?
as it's expected in many years to come ..It's a possibility that one partie or the judge itself ask the full CVR recording (I think the judicial experts have already acces to the full FDR listing .. but the public not yet )
Regarding the full CVR (not a partial transcript) I know a case where the court (canadian) asked for have it with succes ( judicial battle about what was exactly with ATC).. and it's in the Toronto AF A340 accident .. IMHO
Last edited by jcjeant; 16th Jul 2012 at 13:45.
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Originally Posted by Lyman
The argument against dual yoke seemed to be based on physical confrontation
what idiot designed a system where by max nose down input on the left stick was canceled by max nose up input on the right stick?
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@ Lyman,
So in the instance of AF447, would a stick shaker be of help at 350K, M 0.8 with the A/P & A/T disengaging shortly followed by a stall warning? Isn't the key here what was recorded on the CVR, "We have no speeds"? If you have no speeds and you have been flying normally, wouldn't that be interpreted as UAS? Wouldn't you then apply the Unreliable Speed Indication/ADR Checklist? So then, you would level the wings and apply 5º pitch and get out the pitch and power tables? Now would a stick shaker shaking help or hurt you accomplishing this as very gentle adjustments of the sidestick are required? Where would the stick shaker get it's information from that wouldn't be erroneous? Would this extra layer of "protection" add to the confusion having not reacted in the correct manner? Wouldn't the designers, engineers and test pilots of the aircraft thoroughly thought through the need for a stick shaker and implications it might present, both positive and negative and concluded the negatives outweighed the positives?
And finally, would the pilots who have or do regularly fly Airbus aircraft, such as Clandestino, be clamoring for sidestick shakers if it were of true benefit? Just asking....
Quote by Lyman: On the contrary, the danger is in the subtlety of the SS, and it's other shortcomings, visibility being one, and I'll add lack of shaker warn to that. BEA have demonstrated that in Alternate Law, the Airbus is mostly vanilla, but untested in STALL, so the basis for a stick (shaker) waiver is found to be awarded in error.
Clandestino has posited, in my opinion, that a shaker is not needed, simply because it is not fitted ...
Clandestino has posited, in my opinion, that a shaker is not needed, simply because it is not fitted ...
And finally, would the pilots who have or do regularly fly Airbus aircraft, such as Clandestino, be clamoring for sidestick shakers if it were of true benefit? Just asking....
I just looked at the CVR transcript for the first time in a while.
What do people think of the sudden smell of ozone, and the sudden change in perceived cockpit temperature (noted by both crew, and sufficient that PF asks PNF if he did something to the A/C).
It seems odd that in an 11 hour flight, this should occur only a minute before presumed pitot freezing
I am sure this has been discussed previously, but I can't find any reference to it.
Thanks in advance.
What do people think of the sudden smell of ozone, and the sudden change in perceived cockpit temperature (noted by both crew, and sufficient that PF asks PNF if he did something to the A/C).
It seems odd that in an 11 hour flight, this should occur only a minute before presumed pitot freezing
I am sure this has been discussed previously, but I can't find any reference to it.
Thanks in advance.
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@slats11:
I think people said a while back that it was consistent with transiting the weather they encountered.
EDIT : Yes.
I think people said a while back that it was consistent with transiting the weather they encountered.
EDIT : Yes.
Ozone smell probably came from the Cb overshoot they were flying near. I believe the top of the Cb was estimated by Meteo France as 52000 feet, and by Vasquez as 56000 feet. Ozone is present in significant amounts near the tropopause and the Cb overshoot reached into the ITCZ tropopause by 6,000 feet according to Vasquez.
The PNF seems to have recognized what it was.
The PNF seems to have recognized what it was.
there is no electronics failure that will fill an aircraft cockpit with ozone. Ozone production requires voltages that are not present. When they stink electronics failures are very distinctly not ozone smells. Phenolic (not used anymore) has a distinctive smell when it burns. Various wire insulation materials have their own distinctive smells. Burned transformer varnish and insulation has yet another smell. Burned carbon composition resistor (not used anymore) is yet another smell. Burned metal film resistors have too little smell to worry about. Burned epoxy fiberglass circuit boards are burned epoxy smell. (Don't ask. It was after three months of 60-70 hour work weeks.) The blue smoke from integrated circuits has little or no smell because it's generally magical and in small quantities. (No, you cannot stuff that blue smoke back inside, either.) When an electrolytic capacitor overheats and dies the odor is "impressive"; but, it is not ozone. A modern cockpit has few if any motors present spinning at high currents and high voltages.
Last edited by DozyWannabe; 16th Jul 2012 at 14:49.
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In my reply at the time, I suggested that Ozone accompanies heated wiring, and electrical fire. It did not play well, but there were artifacts that made a human caused Ozone release possible, the ACARS "WRG" data, and the immediate recovery of the avionics bay in the first moments of seabad acquisition possibilities. Were the recovery team eager to catch the avionics bay and sequester it with special care? Yes, I have smelled the remnants of Lighning strike, and electric motor under great load, the smell is unmistakable.
Listen, we are in an area that can confuse, and I want to call Dozy's attention to it. Both in JD-ee's post, and many of Dozy's, there is this attitude that what someone senses or believes is wrong because they do not understand the data involved. The PF asked about a smell, it was PNF who offered St Elmo, or whatever. It is disturbing that some people believe an explanation that doesn't click with them perforce means that the experience did not happen....or should not continue to be challenged...
The pilot smelled something, else he would not have asked. The explanation given by PNF may have been accurate, it may have been WRONG. We are supposed to be chastened and drop the topic because some one can explain OZONE? What if it was wires burning, or shorting? What if the AP selector was in the circuit that caused this smell? How does supplying an astute answer to anything necessarily answer correctly the question asked? It does not. I would rather keep asking questions if appropriate, and I reserve the right to call any explanation into question. For the record, I believe Lightning was determined not to be in the area.
Listen, we are in an area that can confuse, and I want to call Dozy's attention to it. Both in JD-ee's post, and many of Dozy's, there is this attitude that what someone senses or believes is wrong because they do not understand the data involved. The PF asked about a smell, it was PNF who offered St Elmo, or whatever. It is disturbing that some people believe an explanation that doesn't click with them perforce means that the experience did not happen....or should not continue to be challenged...
The pilot smelled something, else he would not have asked. The explanation given by PNF may have been accurate, it may have been WRONG. We are supposed to be chastened and drop the topic because some one can explain OZONE? What if it was wires burning, or shorting? What if the AP selector was in the circuit that caused this smell? How does supplying an astute answer to anything necessarily answer correctly the question asked? It does not. I would rather keep asking questions if appropriate, and I reserve the right to call any explanation into question. For the record, I believe Lightning was determined not to be in the area.
Last edited by Lyman; 16th Jul 2012 at 15:12.
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Lyman,
JD-EE's comment was in fact addressed directly to you in the original post. I elected to summarise rather than potentially cause discord, but just so we don't get sidetracked, let's have the rest of it.
I repeat : JD-EE is an electrical and electronic engineer of 60 years' standing. I think she knows what she's talking about.
[EDIT : Good catch!]
JD-EE's comment was in fact addressed directly to you in the original post. I elected to summarise rather than potentially cause discord, but just so we don't get sidetracked, let's have the rest of it.
Originally Posted by JD-EE
And, yes, in more than 60 years playing with electronics and electricity I've smelled all those smells above, some under rather dramatic conditions. (Wet slug tantalum capacitors don't stink much at all. They just embed themselves in ceilings. They're not used anymore.)
[to Lyman/bearfoil :] Your fancy is getting too many flights of late. Maybe you should have it take a vacation. It's not in the competition for frequent traveler miles. I know people who could run rings around your imagination.
[to Lyman/bearfoil :] Your fancy is getting too many flights of late. Maybe you should have it take a vacation. It's not in the competition for frequent traveler miles. I know people who could run rings around your imagination.
[EDIT : Good catch!]
Last edited by DozyWannabe; 16th Jul 2012 at 15:20.