AF447 wreckage found
I drink gin and tonics in the back. Give it up boys, an aoa monitor would have made no difference here.
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Apparently applying nose down control with the side stick is about as effective as selecting page 94 of this thread. The thread defaults to 93. I guess the flight program defaults to stall.
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AoA surely is valuable information, but if nose points 16 deg up and altitude is going down, one would assume figuring out that there's a sh*tload of AoA doesn't really take a rocket scientist?
So maybe they didn't believe what any of their instruments were telling them - still they must have remembered climbing to FL350 - how can 16 deg NU attitude seem like a good idea up there unless you're trying to massively bleed off speed (then you're somewhat unlikely to select TOGA I guess?) or flying a Blackbird?
The more one thinks about it, the less sense it makes.
So maybe they didn't believe what any of their instruments were telling them - still they must have remembered climbing to FL350 - how can 16 deg NU attitude seem like a good idea up there unless you're trying to massively bleed off speed (then you're somewhat unlikely to select TOGA I guess?) or flying a Blackbird?
The more one thinks about it, the less sense it makes.
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AoA surely is valuable information, but if nose points 16 deg up and altitude is going down, one would assume figuring out that there's a sh*tload of AoA doesn't really take a rocket scientist?
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Canyonlight
If you will observe, the next potential page is set up prior to the exhaustion of the current page. If you select the next page prematurely, it defaults to the current page.
Apparently applying nose down control with the side stick is about as effective as selecting page 94 of this thread. The thread defaults to 93. I guess the flight program defaults to stall.
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BOAC
With all (genuine) respect, BOAC, in my view the BEA's use of the word 'slightly' is valueless (like much of the rest of the document) since the BEA provides no information at all on how much turbulence was being experienced before the increase (whether 'slight' or not)?
That there WAS an increase is clearly shown by two paragraphs in the note:-
So the facts are that the flightcrew warned the cabin about likely additional turbulence, and then, two minutes later, diverted 12 degrees to the left of course and reduced speed.
Perhaps 'severe' was too strong a word; and I'll happily substitute 'significant' if you prefer it. But you'll know much better than I do that airline pilots hate diverting or reducing speed unless they have to, because it means delays.
So I hope that you'll agree that there's little doubt that turbulence was a factor in the early stages of the accident?
And moving on from there, one has to wonder why the BEA used the word 'slightly' at all, when it provides no evidence at all to back it up - and, I repeat, no information at all on what level of turbulence was occurring before said increase?
RWA and all the other boys and girls here - I'm sorry to bang on about this, but please stop MAKING THINGS UP!
Quote:
Originally Posted by BEA Report
The level of turbulence increased slightly
- NB NOT 'Severe Turbulence'
Please try to stick to the given facts - it only confuses the thread.
Quote:
Originally Posted by BEA Report
The level of turbulence increased slightly
- NB NOT 'Severe Turbulence'
Please try to stick to the given facts - it only confuses the thread.
That there WAS an increase is clearly shown by two paragraphs in the note:-
At 2 h 06 min 04, the PF called the cabin crew, telling them that "in two minutes we should enter an area where it’ll move about a bit more than at the moment, you should watch out" and he added "I’ll call you back as soon as we’re out of it".
At 2 h 08 min 07 , the PNF said "you can maybe go a little to the left […]". The airplane began a slight turn to the left, the change in relation to the initial route being about 12 degrees. The level of turbulence increased slightly and the crew decided to reduce the speed to about Mach 0.8.
At 2 h 08 min 07 , the PNF said "you can maybe go a little to the left […]". The airplane began a slight turn to the left, the change in relation to the initial route being about 12 degrees. The level of turbulence increased slightly and the crew decided to reduce the speed to about Mach 0.8.
Perhaps 'severe' was too strong a word; and I'll happily substitute 'significant' if you prefer it. But you'll know much better than I do that airline pilots hate diverting or reducing speed unless they have to, because it means delays.
So I hope that you'll agree that there's little doubt that turbulence was a factor in the early stages of the accident?
And moving on from there, one has to wonder why the BEA used the word 'slightly' at all, when it provides no evidence at all to back it up - and, I repeat, no information at all on what level of turbulence was occurring before said increase?
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RWA - my position on the 'paucity' of information released by BEA is on record on the site. I agree we have only a 'subjective' assessment of turbulence, but it is pretty much standard practice that if moderate or worse is expected, the cabin will be told to secure carts etc and get the pax and then themselves seated and strapped. I cannot see AF being different there but with so many vital clues missing from the published CVR extracts we do not know. Of course turbulence was present, but the experts opinion is that it would have been 'average' ITCZ turbulence. From what little is published, it appears the pilots took the appropriate action initially - warn the crew, adjust route. Based on what little I see so far I do NOT consider turbulence to have been a contributory factor in the accident.
I am trying to stop the growing spread of the 'urban legend' that they "flew blindly and stupidly into the mother of all CBs". As long as that remains unproven (and unposted), I am happy. As I and others have said, there are significant and meaningful chunks of flight deck comment missing from the release for some reason which may well hold an explanation as to why they zoom climbed, for example, which precipitated the stall.
I have commented in Tech Log also on the Atlantic incident in 2001 where an A340 did a similar zoom - without crew input - and its speed reduced to a very low figure too. Way to go.
Edit to correct my error on Vls
I am trying to stop the growing spread of the 'urban legend' that they "flew blindly and stupidly into the mother of all CBs". As long as that remains unproven (and unposted), I am happy. As I and others have said, there are significant and meaningful chunks of flight deck comment missing from the release for some reason which may well hold an explanation as to why they zoom climbed, for example, which precipitated the stall.
I have commented in Tech Log also on the Atlantic incident in 2001 where an A340 did a similar zoom - without crew input - and its speed reduced to a very low figure too. Way to go.
Edit to correct my error on Vls
Last edited by BOAC; 27th Jun 2011 at 10:40.
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Re unavailable pages, as posted by somebody else, when posts reach a number higher than ending in 00/20/40/60/80, a new page is generated. If Mods. delete some so the “latest” is now within the 00/20 etc. range, the new page number is visible but has no entries and it was said that we can’t get into it.
Look at the most recent post number. If lower than 00/20 etc., there is no accessible next page. If 00/20 etc., there may be another on the next page, or maybe not yet – just have to try it.
Hope that helps.
Look at the most recent post number. If lower than 00/20 etc., there is no accessible next page. If 00/20 etc., there may be another on the next page, or maybe not yet – just have to try it.
Hope that helps.
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RetiredF4 wrote: Computers and all other stuff built in to modern FBW aircraft don´t either, but they are deemed necessary anyway. Because they help and assist to implement airamship and flying skills, as an AOA indicator would do as well.
Otherwise we could argue about what is really necessary besides airmanship and flying skills:
A cup of coffee: When the coffee leaves the cup, you are flying upside down.
And a cigar: When it is finished, it´s time to land.
AOA indicator necessity is a function of aircraft handling qualities and mission. It is neccessary in F4 where above 15 units AOA you start using pedals for lateral control, and approach using 19. Otherwise you may depart its operating envelope. In A4 you need it for carrier landings, but don't for airbase operations, although it could be more accurate than airpspeed for determination of climb airspeed, cruise airspeed, endurance airspeed etc...
If it were mandatory, it wouldn't be offered as option, e.g. most Boeing passenger transports. Like ashtrays.
Otherwise we could argue about what is really necessary besides airmanship and flying skills:
A cup of coffee: When the coffee leaves the cup, you are flying upside down.
And a cigar: When it is finished, it´s time to land.
AOA indicator necessity is a function of aircraft handling qualities and mission. It is neccessary in F4 where above 15 units AOA you start using pedals for lateral control, and approach using 19. Otherwise you may depart its operating envelope. In A4 you need it for carrier landings, but don't for airbase operations, although it could be more accurate than airpspeed for determination of climb airspeed, cruise airspeed, endurance airspeed etc...
If it were mandatory, it wouldn't be offered as option, e.g. most Boeing passenger transports. Like ashtrays.
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BOAC, we do have the report of one 'expert' on conditions along the airway that night, someone who was actually there and not in some chair greatly separated by distance and time.
The original in French:
IB6024 was 12 minutes behind AF447 (before it deviated, and before AF447 looped in its heading).
For reasons known only to the BEA, the interactive track map that was subsequently released omitted both this flight and the Lufthansa 744 that was 20 minutes ahead, and which deviated to a lesser extent. (The LH track can be traced somewhat by the AMDAR record.)
I will leave it to native Francophones to correct, but I believe turbulence forte is usually translated as severe turbulence.
When passing the INTOL waypoint, they [IB6024, a 340 at FL370] encountered conditions typical of the inter-tropical convergence zone. These conditions were particularly severe 70 NM to 30 NM before the TASIL waypoint. They moved away from the route by about 30 NM to the east to avoid cumulonimbus formations with a significant vertical development, and then returned to the airway in clear skies close to the TASIL waypoint.
En passant le point INTOL, il rencontre des conditions typiques de la zone de convergence intertropicale. Ces conditions sont particulièrement fortes de 70 NM à 30 NM avant le point TASIL. Il s’écarte de sa route d’environ 30 NM vers l’est afin d’éviter des formations de cumulonimbus à fort développement vertical puis la rejoint, en ciel clair, à proximité du point TASIL
For reasons known only to the BEA, the interactive track map that was subsequently released omitted both this flight and the Lufthansa 744 that was 20 minutes ahead, and which deviated to a lesser extent. (The LH track can be traced somewhat by the AMDAR record.)
I will leave it to native Francophones to correct, but I believe turbulence forte is usually translated as severe turbulence.
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Macinbird wrote:
Incorrect statement, the aircraft was nose high, low airspeed far below minimum for the configuration, weight and airmass instability, sinking like a rock.
What about the "stall stall stall" warning you say? Unfortunately that occurred in a context where its validity was called into question. That is why AOA indicators could have helped.
Needs no complex evaluation to determine flight condition and corrective actions. AOA indicator would confirm it, and the stall warning is obvious.
Did you use your AOA as you flew, or did you consider it redundant?
When the airspeed packs up and anytime you are flying slowly, it can tell you quite a lot about your aircraft's performance potential.
Were your airmanship and flying skills as good at 0200 in the morning as they were at 1000 in the morning? If you had been in one of the front office seats in AF447 when the airspeed went South, are you certain it would have been a non-event for you?
I am not the typical airline type. As chief experimental pilot with decades experience, who determines the authorized flight envelope by flying out of it (for example, to determine VMO [maximum operating airspeed] we fly at 125% its value), and writes pilot manuals and procedures including stall recovery.
In my operational flying, I am better at 2 am, because I know the associated problems and make proper advance preparations. I never use any questionable chemical substance, not even anti-perspirants which poison your body with aluminum, but instead deodorants which lack it (most readers don't know that).
Part of the AF447 crew problem that night must have been stall recognition. The flying qualities in the stall were too much like normal flight. Should that be a certification issue?
What about the "stall stall stall" warning you say? Unfortunately that occurred in a context where its validity was called into question. That is why AOA indicators could have helped.
Needs no complex evaluation to determine flight condition and corrective actions. AOA indicator would confirm it, and the stall warning is obvious.
Did you use your AOA as you flew, or did you consider it redundant?
When the airspeed packs up and anytime you are flying slowly, it can tell you quite a lot about your aircraft's performance potential.
Were your airmanship and flying skills as good at 0200 in the morning as they were at 1000 in the morning? If you had been in one of the front office seats in AF447 when the airspeed went South, are you certain it would have been a non-event for you?
I am not the typical airline type. As chief experimental pilot with decades experience, who determines the authorized flight envelope by flying out of it (for example, to determine VMO [maximum operating airspeed] we fly at 125% its value), and writes pilot manuals and procedures including stall recovery.
In my operational flying, I am better at 2 am, because I know the associated problems and make proper advance preparations. I never use any questionable chemical substance, not even anti-perspirants which poison your body with aluminum, but instead deodorants which lack it (most readers don't know that).
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there WAS an increase is clearly shown by two paragraphs in the note:-
At 2 h 08 min 07.....the level of turbulence increased slightly and the crew decided to reduce the speed to about Mach 0.8.
This is very close to the LH crew testimony :
Flight LH507
Flight LH507 (B747-400) preceded flight AF447 by about twenty minutes at FL350. The crew reported that it flew at the upper limit of the cloud layer and then in the clouds in the region of ORARO. In this zone they saw green echoes on the radar on their path, which they avoided by changing their route by about ten nautical miles to the west. While flying through this zone, which took about fifteen minutes, they felt moderate turbulence and did not observe any lightning. They lowered their speed to the speed recommended in turbulent zones. They saw bright St Elmo’s fire on the windshield on the left-hand side.
Flight LH507 (B747-400) preceded flight AF447 by about twenty minutes at FL350. The crew reported that it flew at the upper limit of the cloud layer and then in the clouds in the region of ORARO. In this zone they saw green echoes on the radar on their path, which they avoided by changing their route by about ten nautical miles to the west. While flying through this zone, which took about fifteen minutes, they felt moderate turbulence and did not observe any lightning. They lowered their speed to the speed recommended in turbulent zones. They saw bright St Elmo’s fire on the windshield on the left-hand side.
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Read
Saturn V, #1868,
you are correct in your statement that the French words
"Ces conditions sont particulièrement fortes"
can be translated into the English words
"These conditions were particularly severe".
But where in this little piece of text do you see the word "turbulence"?
The typical ITCZ conditions that were particularly severe may mean that there were more CB's than usual, so a little more deviating action than usual could be necessary.
Once again, as BOAC has stated many times now, it is not at all necessary to fly through the middle of a CB, in order to get the pitot icing problem. I have seen the TAT anomaly (TAT probe icing due to high ice crystal content) when flying through "light green" radar returns in the neighbourhood of CB's, in other words, while avoiding CB's. Turbulence then was only light, occasionally moderate, nothing out of the ordinary. Saint Elmo's and a sound like rain on the windscreen were also present.
Certainly it is problematic that on certain Airbus types the pitot heating can be overwhelmed by ice crystal icing, that's why a recommendation has been made to change the type of pitots, even before AF447 happened, but the outcome of the accident has much to do with basic pitch and power flying. Remember, four perfect attitude sources where always available, showing a very unusual 15 degrees nose up attitude at high altitude.
you are correct in your statement that the French words
"Ces conditions sont particulièrement fortes"
can be translated into the English words
"These conditions were particularly severe".
But where in this little piece of text do you see the word "turbulence"?
The typical ITCZ conditions that were particularly severe may mean that there were more CB's than usual, so a little more deviating action than usual could be necessary.
Once again, as BOAC has stated many times now, it is not at all necessary to fly through the middle of a CB, in order to get the pitot icing problem. I have seen the TAT anomaly (TAT probe icing due to high ice crystal content) when flying through "light green" radar returns in the neighbourhood of CB's, in other words, while avoiding CB's. Turbulence then was only light, occasionally moderate, nothing out of the ordinary. Saint Elmo's and a sound like rain on the windscreen were also present.
Certainly it is problematic that on certain Airbus types the pitot heating can be overwhelmed by ice crystal icing, that's why a recommendation has been made to change the type of pitots, even before AF447 happened, but the outcome of the accident has much to do with basic pitch and power flying. Remember, four perfect attitude sources where always available, showing a very unusual 15 degrees nose up attitude at high altitude.
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Saturn -it would help if you would lay your cards on the table with all this back and forth stuff - most indications we have so far.are that we have NO evidemce that the crew penetrated an active CB, either from a 'separated' armchair or anywhere. You obviously believe they did. Why not state so and declare your evidence please?
I think 'turbulence forte' was discussed extensively on thread 1. I believe it was said to be a non-'standard' grading and thus thought to be subjective. I also think the report was sent well before the LOC. Had it been 'severe' (in your words) the a/c would most probably have been forced to turn back or descend to avoid LOC at that point and/or structural damage and injury to crew and pax. Even your quote from your 'armchair expert' did not consider the weather conditions there to be exceptionally bad.
So - let's hear your facts?
I think 'turbulence forte' was discussed extensively on thread 1. I believe it was said to be a non-'standard' grading and thus thought to be subjective. I also think the report was sent well before the LOC. Had it been 'severe' (in your words) the a/c would most probably have been forced to turn back or descend to avoid LOC at that point and/or structural damage and injury to crew and pax. Even your quote from your 'armchair expert' did not consider the weather conditions there to be exceptionally bad.
So - let's hear your facts?
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Gerard C, of the three other flights on the track that BEA references, the LH reported moderate turbulence and deviated to the west, the IB chose to deviate 30NM to the east, and said conditions were severe. AF459 deviated 20 NM to the west, then chose to deviate 70-80 NM to the east of the track. (The summary of AF459 indicates they encountered unexpected turbulence at NATAL, and immediately began adjusting their radar, but there is no further mention of conditions they encountered, only what they saw on their radar.) So I don't know how you conclude that going in one direction off the track produced a smoother ride. (AF447 deviated slightly to the west.)
EMIT, as noted in the BEA's first interim report,
The narratives of the other flights as published by the BEA are incomplete, and the BEA has not yet provided any additional information. The BEA has also chosen to not release transcripts of the other flights' communications with ATLANTICO. Are there descriptions of conditions being encountered in their communications with ATLANTICO?
(The BEA summarizing seems to contain at least one error: the LH is said to be at FL 350; but the AMDAR trace says 325.)
I agree we have to await the full CVR transcript to see how situationally aware the flight crew was of the weather they were encountering. For example, did they adjust the mode and tilt of the radar, as AF459 did? If they had, and there was discussion of such on the CVR, would you think the BEA might have mentioned that in their most recent note?
EMIT, as noted in the BEA's first interim report,
the BEA made a list of flights close to airway UN 873 during the night of 31 May to 1st June 2009 and asked crews for testimony. Not all of the information requested has been received at present. The testimony summarised hereafter is representative of the information already analyzed.
(The BEA summarizing seems to contain at least one error: the LH is said to be at FL 350; but the AMDAR trace says 325.)
I agree we have to await the full CVR transcript to see how situationally aware the flight crew was of the weather they were encountering. For example, did they adjust the mode and tilt of the radar, as AF459 did? If they had, and there was discussion of such on the CVR, would you think the BEA might have mentioned that in their most recent note?
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BOAC, I don't believe they knowingly and purposefully flew into a meso-convective complex with cells that were overshooting to FL 520 or 560.
I do have questions, suspicions if you will, about how aware they were of the weather they were encountering. I do wonder whether and why their perceptions of the outside environment were so different from the flights following that they continued on, and the other flights chose to avoid. Clearly, the actions of the crew of AF459 following, with the same plane model, same radar, presumably the same AF training and procedures, on encountering the amas between ORARO and TASIL were dramatically different. How to explain or reconcile the actions of the two AF flight crews?
I do have questions, suspicions if you will, about how aware they were of the weather they were encountering. I do wonder whether and why their perceptions of the outside environment were so different from the flights following that they continued on, and the other flights chose to avoid. Clearly, the actions of the crew of AF459 following, with the same plane model, same radar, presumably the same AF training and procedures, on encountering the amas between ORARO and TASIL were dramatically different. How to explain or reconcile the actions of the two AF flight crews?
Originally Posted by GerardC
I agree with "BOAC", there WAS a turbulence increase but, since they only elected to reduce speed at 2h 08, the level of turbulence before that time must have been very benign ideed.
The conditions previous to upset are not as important (in terms of understanding pilot response) as conditions during the period 2:10 to 2:14.
As we all know, conditions change in the vicinity of big buildups. Sometimes those changes are significant. The crew expected some change in conditions before the course correction of 12 degrees. There is no guarantee that their correction was sufficient, though it may have been. It also could have been insufficient, with a result of flying into turbulence that they'd expected to avoid by the course change.
One useful piece of non-evidence that we can work with is lack of evidence of an action taken: absence of further warning to the CC to secure the cabin for turbulence.
I do not feel it reasonable to rule out the possibility that a change in condition was coincident to the other problems they encountered.
The well asked question is then: why no alert to the cabin crew? When things get rough, it is standard practice to have the CC secure the cabin.
Aviate, navigate, communicate is also standard. Crew got very focused on aviate, and were having sufficient trouble with aviate to summon the Captain. That is a possible accounting for the non-call to the CC to secure the cabin.
Admittedly, this doesn't give an answer, it just raises another question. So be it, only so much information to work with.
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BOAC, I don't believe they knowingly and purposefully flew into a meso-convective complex with cells that were overshooting to FL 520 or 560.
The 'difference' you query could be explained by the fact that they were two different crews who 'read' the situation differently. Also in 10 minutes a cell can move quite a distance in relation to an avoid distance of 20 miles or so, so the question is not what 449 or IB did, but what 447 did. If I had 2 Drachma for all the different interpretations of 'weather' I have seen in my career I would be able to rescue Greece from bankruptcy.
As you say, the information from the other flights (and 447) is not complete. We do not know, for example what they saw or decided weather-wise after the CVR 'left 12 degrees'.
I do not understand why you do not accept that at the moment the accident APPEARS to have been primarily triggered by pitot icing in cloud - not a CB. Cloud is pretty difficult to avoid at night.