bomarc,
Look at post 1632. He does a great job of explaining how the TL system works and possible failures that could cause TLA false readings. |
yes bubbers, I read it; also something not posted that makes alot of sense.
TO NIGEL ON DRAFT: in your own post, you use the word "ALMOST". <<<This shows you know nothing about aviation, and accident investigation in particular. Almost all accidents>>> by using the word ''almost'' even you allow for a possibility. I take great offense that you say I know NOTHING about aviation. I even know who the pitot tube was named after. ;-) BUt I think you might learn something about thinking outside of the box by my little challenge. to all responding to my post, especially soaring the skies and slip and turn... you understand. you understand that I am using an old debate technique. One that challenges you to think outside of your position...to take the other side, to challenge your mind to be open to help find the truth. thank you for understanding! |
So often in life the most difficult thing is to know when to quit.
|
I believe the psychologists tell us that when we become overloaded the first sense which the brain "deletes" is that of hearing. This has happened on several incidents where, for example, the non flying pilot has been making comments on the operation but the flying pilot has not "heard" the comments.
I am not saying this has happened with this accident but you can have all the aurul callouts in the world going but if they dont reach the brain(s) of the humans they are unlikely to respond in overload situations. Without prejudging the full report I think this accident only goes to prove the Swiss cheese model -it's never one thing but when all the holes line up....... |
Translation
Perhaps even us Brazilians here will disagree and this is OK. But from my perspective, if one of us tell the other to "desacelerar" this has only one meaning: "reduce thrust". If one wanted to tell the other to brake he would have said: "freiar". And if one tell the other "não consigo" he means that he tried and discovered that he could not complete the action.
Mind you the "desacelerar" in the transcript came from an english translation of what was said, as done at the NTSB. One would have to listen to the tape and the voices to learn what the pilots really said in portuguese. Anyone has done this? But "desacelerar" in usual portuguese will never mean "slow down". It could mean "slown down in the contect of reducing thrust". Do you know how it is called the thrust pedal in a car: "acelerador". |
Dani
If someone wants to insinuate that the TL no 1 was stuck in climb mode, that still doesn't take away the blame from the pilots. What would you do in a split second if you see that it's stuck and engines are not spooling down? Right, cut the engine by the fuel lever, called Master Switch on the Airbus. Lemurian with the very unusual dual autopilot configuration which one only uses for an autoland. Cheers, TP |
TyroPiccard, EXACTLY!!
That's what I always try to say. This means that up to touchdown, there was nothing wrong, or at least the crew was not aware that something was wrong. If there would have been - zack! Go Around! This means nothing else that the problem started AFTER touchdown. I still don't find any argument against my reasoning: They touched down, thought that they shouldn't touch the "faulty" engine no. 2, left it where it was, no deceleration, the rest is history. Dani |
Since we are now at the CVR, don't forget the PF says: "Olha isso!" (Look this!) one second before PNF said: "Desacelera, desacelera!" (decelerate, decelerate!). PF then says: "Não dá, não dá" (closest translation would be: I can't, I can't or can't do, can't do)).
And also something like : It's rolled (?) (Está enroscado) was said by the PF, (according to the local press at the time CVR was made "public") but I can't see it on the voice transcripts (page 12 of the FDRs). |
Dani
I thought you would have shut down the engine? TP |
marciovp raised this interesting "if"
• If the co-pilot also had a long experience with A-320s... I think more relevant questions would be .. How often had the PNF flown RHS, and how recently? Is there any evidence that two Captains are more or less safe than a properly constituted crew? Any Airbus FBW FDR experts about? Page 2: From 18:48:20 to touchdown four seconds later I would expect to see increasing back stick in the flare. Instead, on the graph Stick Long-L the stick goes to 4° back then neutral then 9° forward then neutral. Full deflection is 20° so 9° is a sizeable nose down input about one second before touchdown. From first WOW there is dual stick input - RHS has a fairly steady 1 to 2° back stick for 6 seconds, during which LHS goes to 6° back to land the nosewheel. Not something you usually do. Is the Stick Long - L graph representative of usual stick position in the flare? Cheers, TP |
Dani
They touched down, thought that they shouldn't touch the "faulty" engine no. 2, left it where it was, TP |
Arrgh, TyroPiccard, keep it simple, please! Read all my posts.
If you are in the air, and your TL is stuck, you go around. If you are on the ground, you brake on one engine already, and your other TL is stuck, you don't go around, you cut the engine. Of course I don't know what happened, I'm no wizzard. I just say what the most plausible answer is. You can find here thousands of theories. According to Ockham's knife (read this theory!), mostly the most simple theory is the correct one. Dani |
TP,
please educate me on this. I imagine that all this GS logic is to avoid a situation where the pilot wants to go around after touchdown, and he has ground spoilers up. But I learned from this thread that less than a second after touchdown, pilots are engaging T/R (it's OK to do it even if you don't have nose WoW). When he decides to go around after touchdown with T/R (not recommended?), the time it takes to go from reverse to forward thrust wouldn't be enough to also "close" GS (also automatically)? What I am trying to say is: Why not make GS available if EITHER TL is at reverse? thanks Rob |
Maybe it is time for a summary of the story so far? This seems about right to me.
Originally Posted by madherb
As I understand things so far:
This is all very interesting; however the consensus seems to be that the aircraft could have been stopped within the distance available, had some sort of failure/error not occurred which prevented:
I'm certain this will have a large effect on AB training programmes. It appears that a lot of 'traditional' sensory input is now indicated on a screen. I recall well the time it took me to adapt on the 737 to look at the Flight Mode Annunciators to see which mode I was in rather than the button I had just pressed. Are all AB pilots made fully aware of this change of emphasis? Now we have a clever system with lots of circuits/logic gates and what-have-you chuntering away all the time doing what it thinks the pilot wants. The problem is when what it thinks you want and what you actually want are not the same. We can go back to the beginnings of AB history and see the same problem - the Indian crash, the Strasbourg crash, Habsheim. Each time, I assume, the training system adapted. It appears it needs to again. There was, and often is, not enough time to go through a logical sequence of the 'what-is-it-doing-now' process. We need some memory items that can be drilled into heads so reaction becomes 'automatic'.
Originally Posted by woodvale
I was able to do 3 relight attempts because they were drills etched into my brain and practiced monthly in the Sim, absolutely no thinking required to do them.
Originally Posted by SoaringThe Skies
In aviation, memory items are design to reside exactly here, in procedural memory. Repetition makes memories go there over time. Procedural memory is very fast to access, it's usually very simple stimulus-action type of memory.
We appear to be down to: either they forgot to retard number 2 OR they did retard it but there was some sort of failure which told the machine that it was not retarded. I do not think we will ever know. It is pretty certain that there was no throttle 'jam', or someone would have commented during the flare/landing. Unfortunately the position of the number 2 TL in the wreckage will not confirm where it was on the runway. Who knows if anyone moved it during those last frantic seconds? Maybe there is something in the FADEC (if it has a 'memory' which survived) or elsewhere in the data banks. There were certainly a few holes in the well-known cheese. Lastly, for reference, the latest FDR reading is here and the CVR translation is here. Although a 30 minute loop would probably not give us the landing briefing, I am puzzled by the 'missing' 20 minutes on the CVR? Anyone know where it went? |
Dani
I tend not to write long-winded posts, but just for you.... What I mean is: when you retard the thrust levers in the flare and discover that one of them will not move, it is instinctive to go-around/reject the landing and take the problem into the air. I think every airline pilot would do the same on a short wet runway with no grooving and an Inop T/Rev in addition. It would not even cross my mind to think about Ground Spoilers logic or autobrakes.. if that lever is stuck go flying again! One in TOGA and one doing it's own thing will get you airborne again. You, on the other hand, suggested shutting down the engine immediately, which I happen to think is the wrong course of action. TP |
Now there have been the most sophisticated and intellectual contributions on more than 1800 answers to this thread ..... and still there is a mystery and 1801 different oppinions by AB wizards.
But .... if the thing would have been designed to move .... the pilots may have realised that thrust was still on .... and might have simply pulled back the levers. It's so simple .... food for thought. |
BOAC
"Missing" CVR - we have only seen what "they" want us to see. TP |
I imagine that all this GS logic is to avoid a situation where the pilot wants to go around after touchdown, and he has ground spoilers up. Maybe somebody will correct me, but I think it's more the other way around: it's to avoid at all cost deploying GS (which destroy lift and act like speedbrakes) a tad before touchdown, and shoving the u/c through the wings as a result. |
It;'s both really, but the in-air deployment case can get very bad, very quickly.
GS destroy a LOT of the lift on the wing. To the extent there may be almost NO lift. The gear is designed to a 10ft/sec impact. Drop an aircraft (or anything else) purely free-falling from 10ft and the impact velocity will be of the order of 20ft/sec. Twice the design velocity, 4 times the design energy. That's going to break a lot of bit of aircraft if it happens. (You'll note that the radalt threshold for "on ground" is usually set down at 5-6ft, to minimise the impact in the event of a deployment at the radalt limit) |
BOAC, very good post, on which all further posts should be based on.
Except for: Unfortunately the position of the number 2 TL in the wreckage will not confirm where it was on the runway. Who knows if anyone moved it during those last frantic seconds?
Please compare the FDR printout. The TLA engine 2 stays constant. In the CLB detent. It's pretty obvious that they "forgot" about the TL 2... Dani |
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