AF 447 Thread No. 12
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Well .. it's not really a argument
Pitot is not a new technology .. icing and deicing of Pitot is not new knowledge
All will result in 3 different erroneous Pt measurements.
I think this was enough time for find a system for alert the crew that a Pitot is out of use .. by audible or visible alarm
If the heater fails this is announced otherwise freezing is only a temporary issue.
Apart from icing it could be blocked and/or damaged by other means (bugs/birds/radome/mechanical damage).
It would need additional sensors (which are pronounced to fail by itself due to the severe environment) and computers to supply an reliable specific PITOT failure message, and - once again - all failures would lead to Pitch and Power.
Last edited by A33Zab; 31st Oct 2014 at 04:00.
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Winnerhofer/Join Date: Oct 2013/Location: Wengen/Age: 44/Posts: 281
A computer did not cause this accident- the copilot did...
Basic CRM doctrine says that the crew were supposed to act as a team - working together to solve problems, and they did not. AF - aware that their A330 fleet used Thales AA probes - were supposed to pass relevant info regarding UAS procedures to their crews and they did not. Airbus may have dropped a failsafe point on THS movement between the A320 and A330 design. The only important question is why.
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Originally Posted by DozyWannabe>
...either he retired two years ago, at age 42 of career, either there is a slight dysgraphia symptom
Here you're talking, so why? Why the THS and AOA indicators are not mandatory?
Either your profile age is dodgy, or there's something else fishy going on...
Airbus may have dropped a failsafe point on THS movement between the A320 and A330 design. The only important question is why.
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Originally Posted by A33Zab
No we don't agree, pitot failures are clustered and result in NAV ADR DISAGREE (if value and time constraints are exceeded).
This crew at that time needed to do the comparison themselves and take the appropriate action (pitch and power) like it was done for many years.
This crew, as anyone who actually fly the thing, just needed the good honest briefing that Airbus missed the opportunity to publish ...
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Winnerhofer, read the previous umpteen thousand posts before coming to the conclusion that the pilots were incompetent, please!
Now back to looking for Spaceship Two info.
Now back to looking for Spaceship Two info.
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jcjeant, considering the various regulations; a requirement for an indication of failure is not the same as an indication of system state. The pitot did not ‘fail’, the problem was that the data was not reliable.
Similarly before considering the ‘risk of error’, what is an error? A system should be designed to minimise risk, but it cannot ensure that there is no risk, nor any error.
Winnerhofer, irrespective of your experience with ASI problems, what was the experience in unusual ice crystals. And please do read a HF reference on the limits of human performance.
As per CONF iture’s link, Airbus had associated the pitot deficiency with ice crystals. Unfortunately, the manufacturer, regulator, operator, or all, continued to focus on the pitot system as the threat (flight with UAS) instead of the conditions which triggered the system problems.
Looking at this accident with hindsight, and with a ‘safety 2’ view (resilience – the human as a help not a hazard), a backward search can identify a situation where a crew’s normal behaviour could have avoided the pitot ‘failure’ situation – by avoiding ice crystals / cbs. The normal everyday behaviour, opposed to LoC recovery, would be using Wxr to deviate around cbs, with a greater distance margin due to an awareness of the ice crystal threat.
Comparing flight paths with other aircraft this operation might be questioned, as might the crew’s knowledge of the ice crystal threat as above.
Thus the safety weakness was with an incorrect choice of threat, possibly aided by considering the human as a hazard, requiring refresher training.
Similarly before considering the ‘risk of error’, what is an error? A system should be designed to minimise risk, but it cannot ensure that there is no risk, nor any error.
Winnerhofer, irrespective of your experience with ASI problems, what was the experience in unusual ice crystals. And please do read a HF reference on the limits of human performance.
As per CONF iture’s link, Airbus had associated the pitot deficiency with ice crystals. Unfortunately, the manufacturer, regulator, operator, or all, continued to focus on the pitot system as the threat (flight with UAS) instead of the conditions which triggered the system problems.
Looking at this accident with hindsight, and with a ‘safety 2’ view (resilience – the human as a help not a hazard), a backward search can identify a situation where a crew’s normal behaviour could have avoided the pitot ‘failure’ situation – by avoiding ice crystals / cbs. The normal everyday behaviour, opposed to LoC recovery, would be using Wxr to deviate around cbs, with a greater distance margin due to an awareness of the ice crystal threat.
Comparing flight paths with other aircraft this operation might be questioned, as might the crew’s knowledge of the ice crystal threat as above.
Thus the safety weakness was with an incorrect choice of threat, possibly aided by considering the human as a hazard, requiring refresher training.
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Would they have been to able to override AutoTrim with StabTrim in ALT 2B?
Manual inputs override all other stab trim inputs on the A330, but if you let go of the trim wheel, the system will try to take it back to where it computes the trim needs to be.
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Hi CONF iture,
Correct, AFS = Δ 20kts 425ms, apparently they don't want the 'logical but with lack of intelligence' AP to make inappropriate actions.
EFCS ALTN = Δ 30kts 1s compared to median @ T-1, latched > Δ 50kts after 10s compared to median @ T-11
No bizarre ALTN LAW, THE only ALTN LAW (PROT LOST) as it is announced.
PROT LOST = NO protections.
The 'reason why’ AP dropped off and EFCS reverted to ALTN LAW was direct in view,
on the PFDs, different speed displays / flagged SPD and SPD LIM in capitals, bold and red.
Apparently value and time constraints have been exceeded long enough to command the AP and A/THR to quit and the FCS to switch to a bizarre ALTN LAW but not to announce the reason why, be it NAV ADR DISAGREE ... !?
Correct, AFS = Δ 20kts 425ms, apparently they don't want the 'logical but with lack of intelligence' AP to make inappropriate actions.
EFCS ALTN = Δ 30kts 1s compared to median @ T-1, latched > Δ 50kts after 10s compared to median @ T-11
No bizarre ALTN LAW, THE only ALTN LAW (PROT LOST) as it is announced.
PROT LOST = NO protections.
The 'reason why’ AP dropped off and EFCS reverted to ALTN LAW was direct in view,
on the PFDs, different speed displays / flagged SPD and SPD LIM in capitals, bold and red.
Last edited by A33Zab; 4th Nov 2014 at 11:33.
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I can't see anything in the final report's main body specifically relating to the *latching* of Alt2B, just the flight law change itself, which would obviously occur in a much shorter period of time.
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OK465,
For the EFCS LAW:
The MEDIAN value is polled every second (T0) and compared to the MEDIAN at T0-1s, if the MEDIAN at T0 falls below 30kts of MEDIAN at T0-1s then at T0:
A// The EFCS goes to ALT LAW (ALT2B) and this is announced on ECAM: F/CTL ALTN LAW (PROT LOST)
B// A monitoring timeframe of 10sec is opened and if the MEDIAN value at T0+10s returns within 50kts of the MEDIAN at T0-1s then the EFCS returns to NORMAL LAW.
However if, like in AF447, the difference is more than 50kts then ALT LAW is latched for the remainder of the flight.
Resume: ALT LAW at T0 and LATCHED after T0+10sec.
(Source BEA report #1)
For the EFCS LAW:
The MEDIAN value is polled every second (T0) and compared to the MEDIAN at T0-1s, if the MEDIAN at T0 falls below 30kts of MEDIAN at T0-1s then at T0:
A// The EFCS goes to ALT LAW (ALT2B) and this is announced on ECAM: F/CTL ALTN LAW (PROT LOST)
B// A monitoring timeframe of 10sec is opened and if the MEDIAN value at T0+10s returns within 50kts of the MEDIAN at T0-1s then the EFCS returns to NORMAL LAW.
However if, like in AF447, the difference is more than 50kts then ALT LAW is latched for the remainder of the flight.
Resume: ALT LAW at T0 and LATCHED after T0+10sec.
(Source BEA report #1)
Last edited by A33Zab; 5th Nov 2014 at 04:06.
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Dozy
I understand your curiosity
But what is going to help (interpreting) you to know from where come this text or who is the author (it's plain english)
What is important and that can be analyzed or criticized .. in first place is what is in the text and not the author or the place ...
This can also avoids bias
Apart a netiquette problem of course ...
@Winnerhofer - I don't mean to be a pain, but it'd really make interpreting your posts a lot easier if you could state where your quotes come from.
But what is going to help (interpreting) you to know from where come this text or who is the author (it's plain english)
What is important and that can be analyzed or criticized .. in first place is what is in the text and not the author or the place ...
This can also avoids bias
Apart a netiquette problem of course ...
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@mm43 - Cheers, I did Google it last night. It's actually a comment on the blog IIRC, but I looked up the guys profile and he seems to know what he's on about. I don't know where the first one came from though.
@jcj - One of the fundamental things that my history teacher taught me about critical thinking is that most information is useless unless you have at least some idea of its provenance. By copy/pasting verbatim, Winnerhofer is making it very hard to ascertain the value of the info being posted.
Also, for people reading the forums who aren't regulars (remember that journalists do tend to prowl here from time to time), it won't be at all clear that WH is in fact copy/pasting. This is why we have a [QUOTE] function.
@jcj - One of the fundamental things that my history teacher taught me about critical thinking is that most information is useless unless you have at least some idea of its provenance. By copy/pasting verbatim, Winnerhofer is making it very hard to ascertain the value of the info being posted.
Also, for people reading the forums who aren't regulars (remember that journalists do tend to prowl here from time to time), it won't be at all clear that WH is in fact copy/pasting. This is why we have a [QUOTE] function.
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Question about AirFrance 447
A fellow A-320 Captain and I were discussing the findings in the crash of AF 447 . Was there ever any evidence of in flight break up of the aircraft? Specifically the separation of the vertical stabilizer and rudder? The image of that part of the aircraft floating on the surface seems similar to the same image of the American Airlines A-300 accident at JFK some years ago.
Just curious...
Just curious...
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@Pappy320:
None whatsoever - the vertical stab was still partially attached to the fuselage frames and the break pattern was consistent with detachment upon impact with the ground. See Final report section 1.12.2.6 - "Visual examination of the vertical stabiliser".
None whatsoever - the vertical stab was still partially attached to the fuselage frames and the break pattern was consistent with detachment upon impact with the ground. See Final report section 1.12.2.6 - "Visual examination of the vertical stabiliser".
Winner, all these pointers and references to other incidents have made me curious; are you involved in any aspect of the flight safety programs at your carrier and if so in what capacity? SMS? FDM? Investigations?
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Original Quote by Winnerhofer: An ounce of prevention is worth a pound of cure!
Now, specifically as applying to the A-330 and A-340:
It seems to me, emphasis has been placed on pitot tube icing by both Airbus and Boeing, specifically at high altitudes and high speed. Additionally, training of this situation by airlines together with safety organizations certainly has made flight crews more aware of procedures to be followed when UAS happens, lesson learned from AF-447.
You should keep in mind that UAS resulting from pitot tube icing is a temporary situation that self corrects given the opportunity, 30+ Airbus flight crews proved that point, 1 did not.
Back to the peanut gallery…
