HazelNuts39,

I am rather wondering what the performance of BUSS might be in "unusual attitudes". It is intuitively obvious to me that if the plane can be expected to stay flying "normally" on pitch and power one could work backwards from altitude, pitch, and power to get an airspeed indication when the plane is more or less in a steady state. At reduced accuracy it might even be able to make good guesses while altitude is varying. What's not obvious is what could have been derived from the plane's movements and power settings once the upset had begun. At that time the velocity vector becomes more interesting than mere speed.

BUSS would be good for getting through an upset period if you don't do anything stupid.

rudderrudderrat, "Pilots can only sense accelerations - not speed. The sensation of high speed was due to the unusual air noise around the cockpit sounding like they were going very fast."

Indeed, and they're not as good at it as they think they are. He was leaning back. That felt like acceleration to him. The comment made makes it seem like he was pulling back on the stick to get the nose up to slow down and it wasn't happening. The acceleration was continuing. His brain froze solid.

A full motion simulator can show you this effect happening. And if the training program includes a module to explain how such simulators work maybe then the idea that you cannot trust even the pressure on your back or seat when flying with no visibility at all outside the plane. That brain freeze prevented him from recognizing the stall. (Darnedifiknow what led the PNF to be so meek about breaking through PF's fog. It cost him his life, whatever the reason.)

Now ask the important question. Could the THS deliver ENOUGH lift at any setting to eventually produce an ND attitude? It's not sufficient that the THS and elevator produce lift. It must be sufficient lift to materially affect the orientation of the plane.

As a thought experiment a stiff sheet of cardboard held outside the car window tilted at 60 degrees produces some lift. But it's very small compared to the lift when it is nearly horizontal. And it depends highly on the velocity of the car. Memory if playing with such stuff when I was MUCH younger suggests the curve involved is not a simple lift proportional to some constant times the cosine of the angle relative to horizontal. The upward force needed is, however, proportional to the cosine of the angle of the plane to horizontal.

Can the THS/Elevator combo win this race? I don't have the data to know one way or another. I am sure simply generating lift "ain't enough."

Hi JD-EE,
I disagree.
He would know that with a nose up attitude around 15 degs that the sensation on his back felt normal. Most of the time he held around 15 degs pitch - they didn't exceed 20 degs of pitch at any time. If he was confused about acceleration and pitch attitude he would have pitched up even higher.

Pilots recognise the difference between horizontal accelerations felt on take off and the sensation at some nose up attitude - by using the PFD.
This crew simply used the wrong pitch attitude.

I think he's used the pitch attitude he's associated with TOGA power. OK at low level - but completely inappropriate at cruise FLs and they never recognised the fact they were stalled.

jcjeant, you're annoying. You're starting to ask my kind of questions.

(grinning ducking and running ---->>>>>> that way!)

Really ---

I wrote and posted 520 BEFORE I wrote and posted 519. Something glitched!

Spooky!

What do the pilots know that the computers don't already know? In fact everything the pilots see is filtered by computers. The AF447 pilots were just as blind and bereft of real data as the pilots. So there really is a valid question here. Why DID the pilots have to take over?

The only valid excuse that comes to mind is that the designers did not know this particular failure mode existed. Until this crash the doctrine was that such errors could not happen.

Now, the computer actually has more information than the pilots saw, it appears. At the very least it has AoA. It also has GPS, raw and processed and the inertial system that it can use to work with. It HAS altitude. It never lost it. So it can monitor its pitch and thrust and fiddle both to maintain altitude. It might be a "lumpy" process. But it would keep the plane flying. The pilots may have had the GPS/INS data displayed somewhere. It appears it was as little in their scan pattern as the trim wheels. So it might as well not have been there if it was. The computer would scan these things if the software design had it doing so.

rudderrudderrat - that's the theory. His actions and words suggest he plain forgot, fell back on seat of the pants flying, and died.

02:11:40 "I have the impression (we have) the speed."

How did he get that impression?

Hi JD-EE,
Good question.

If the Autopilot could have remained engaged controlling both pitch and roll - but with a Health Warning such as "ATT", then it would have freed up more brain cells.

What is the point of playing "Keep the Wings Level" with roll direct when faced with UAS?

I would guess from the unusually loud air noise. If they thought they were accelerating, they would have closed the Thrust Levers.

JD-EE, rudderrat. He wanted evidence for overspeed, he found it, and acted accordingly? Brain Lock, dangerous, lethal, at times.

Sometimes, and I have been guilty of it here at times, The human Brain makes up its mind, then looks for evidence in support of conclusion.

Doubt everything, especially one's own opinions. Advice to self.

"I have the Impression...." Linguistically, that is a statement in want of a supporting opinion. If supported by either of the other two pilots, he is affirmed. Then the group can act. PF is too fond of the plebiscite, the election. "Wrong, My Airplane....."

Like the AD's Three, a vote, then?

JD-EE,

You're the expert on this, but trying to program the computer to recognize every possible failure mode (and to avoid confusing them with each other or the failure modes you inevitably failed to anticipate) seems like a much taller order than just progressively shutting down the automation when it becomes apparent something's wrong. Maybe something you could do if starting from scratch today, but not with the technology the A-330 was designed around?

Yes, I agree with that - a nominal 5 degrees pitch, held fast and gently achieved with tiny stick movements, and thrust levers in the CLB detent would not stall the aircraft.

One way of perhaps making a change which retains the essential and necessary actions in the original drill is to modify the qualifying condition at the start of the memorized drill, which is, "If the safe conduct of the flight impacted". There is little guidance on how to make this decision in a hurry. In some explanations, the "safety of the flight is impacted" if all three airspeed indications fail". While such an assessment is probably a wise and accurate one, I disagree that the automatic response to this qualifier in the drill should be a pitch-up to 5deg.

The drill was originally conceived to deal with pitot or static system failures close to the ground, the takeoff phase being the obvious and most critical phase. The memorized items, as I have argued, cater to the takeoff phase, and, I have argued, the "Above FL100" caters to the climb, perhaps even out of high altitude airports, but not to cruise levels where the aircraft is already in stable, level flight. I submit that it is a mistake of interpretation and lack of clarity in the drill, to execute the 5deg pitch-up using this qualifier. This qualifier is followed by three items and the statement, "When at, or above MSA or circuit altitude, level off for troubleshooting". Well, one is already well above MSA and is already levelled off. Why divert from that qualifying condition, only to return to it "quickly", as the "How to do this drill" notes require?

If the memorized items are to be correctly placed and the subjective, very individual assessment as to whether the "safety of the flight is impacted" avoided if the memory actions are qualified not by "the safety of the flight" but by flight phase and by altitude. Then the drill is much more clear as to what actions to take. Qualifying by flight phase and altitude are the first memory items after the "safety of flight" qualifier anyway.

So it might look like this:

DRAFT - DO NOT USE - FOR DISCUSSION ONLY:
http://www.smugmug.com/photos/i-58PX...-58PX24p-M.jpg

As Clandestino has pointed out, these drills and checklists have been created carefully by test pilots and others who know this work thoroughly. The suggestion for change will have implications not imagined or considered and clearly needs examination by many others. But the basic notion is removing the initial qualifier to define more precisely, where different behaviours, (crew responses) will occur. I think that confusion and the training resulting from this confusion is at the heart of the initial pitch-up - what cannot be explained in this view is the immediacy of the response and the absence of SOPs and CRM.

Changing drills and checklists occurs all the time as new knowledge and experience emerge. This is normally done through meetings between checkpilots, standards pilots, flight safety/flight data people and so on and is otherwise a process with heavy vetting of such changes.

In fact, the UAS memory items and ADR Checklist have perhaps half a dozen iterations from around 2001 on - the first drill did not mention "levelling off" at all and was a straight response to the Birgenair and Aeroperu accidents. However, the B727 pitot-icing event pointed out by a poster recently, was not considered, nor, I believe, were pitot failures at cruise altitude until after 2002 or so even though such failures had been occurring since 1996.

There are other serious matters at hand which this accident has made clear. But the accident sequence began with the instant pitch-up, with no SOPs followed, and it is important to establish why this occurred and to take measures to examine and change those reasons.

Pitch and power
 

Which computer? The AP and A/THR disconnected, and handed 'control' to the FCPC, which reconfigured to Alternate law. The purpose of 'pitch and power' is to "keep the plane flying", not to maintain altitude or airspeed (in UAS and in turbulence). The FCPC does just that - maintain pitch and power. Why can't it maintain bank angle?

JcJeant
There is another question - to what extent do simulator exercises provide sufficiently real training for emergencies?

There is a considerable psychological impact that the human factors people seem to have ignored. That is that transferring computer game simulator learning into handling 'real world' emergencies does not work well with all people. In the 'old days' before clever simulators all such training was in the air and if a trainee repeatedly 'lost it' under pressure it became immediately apparent. This weeding out will not happen with sim rides where trainees learn to pass the sim ride.

It could be said that the only reason that pilots are required is for when the automatics fail.

Several posts here have statements like: "The simulator does not perform like the real aircraft after a stall" or "the simulator cannot behave as the real aircraft does outside the normal flight envelope" and even "the simulator does not fly like the real aircraft in Alternate Law"

So the simulator is being used to train pilots in how to handle emergencies, upsets and LOC, despite actually not behaving like the real aircraft in emergencies, upsets and LOC? :ugh:

The current approach of only using simulators for training pilots to fly simulators does not seem extremely logical. I am sure that the accountants love it.

PJ - the problem with your suggestion is that it does not cover all bases, in that with a total baro data failure one could see a crew 'floundering' for a pitch attitude, whereas 5 is SAFE, will not cause a stall from steady cruise and will then give time to enter the trouble shooting phase with pitch/power from the QRH. I really see no need to change OR to worry about the definition/interpretation of 'danger' either. It will work, it will give 'breathing space and it is easy to remember without having to try and find a pitch attitude that produces a steady GPS altitude! Heaven knows the ship is complicated enough without adding to it.

Ian W - indeed - and the exercise is self satisfying in a circular way, since it can be demonstrated that with improved sim time and training sim performance is improved, and it is there that thankfully 99% of our aviation 'nasties' happen. When they happen in the real world we discover the holes.

To my understanding, PJ's suggestion should be in effect exactly the same as the current procedure, just making it easier to decide how it should be applied...

http://tinyurl.com/3or72nd

Thanks BOAC. Yes, I knew there were "holes" and perhaps that's one. The intent is to examine the drill, for all reasons given.

Zorin_75;

Yes, my thought was to keep it as close as possible to the original. Thinking about it, BOAC's critique applies equally to the original drill.

Boldface, OODA and training
 

I am disturbed by some here that believe you can handle an emergency situation or an "upset" ( love that term, and cracks me up and guess it really means "WTF?, over") by following rote, memorized procedures for more than a few seconds.

I am a "professional pilot" or would not have joined the fray here. Granted, folks like me and RF4, Wolf, 'bird, Smilin', et al flew way beyond the envelope I would expect for a pilot hauling SLF and trying to get the zillion $$$ jet safely to the destination. Nevertheless, we had our "boldface" procedures to rely upon for the first few seconds. Then we tried to figure out exactly what was going on and what we could do about it. The ol' OODA loop.

Make no mistake, great cockpit displays and unambiguous caution/warning indications are extremely important. I don't believe the AF447 crew had such.

The stall warning implementation deeply disturbs me. No "stick shaker" gizmo, no clear display of AoA, etc. AF447 was above that 60 knot speed that disregards the AoA, and even if the pitot system was FUBAR and output was zero, the AoA should have been provided in a clear manner to help the crew. Some jets have very benign stall entry characteristics, preceded by mild buffet sans wing rock, little yaw moments, etc. hence the 'stick shaker/rudder shaker" and other gizmos. They told you, GET THE NOSE DOWN!!!

A few here have noted that at high speed the AoA only needs to be changed slightly to get really large changes in gee and pitch changes. True, but the 'bus FBW major pitch law is mainly gee, so big deal. OTOH, once getting slower and approaching or actually in a stall, the AoA is the best gauge, and friend, you have!! It's also super when flying an approach and something is awry with your weight versus approach speed calculations. in other words, it tells you something is wrong. And remember that the plane flies on AoA and not airspeed ( which can go Tango Uniform, as has happened numerous times in the 'bus"). i might add that the Viper AoA versus gee command function reduced available gee command from 9 to 1 as our AoA increased. So at max AoA we could only command one steenkeeng gee!

So I shall still not let Airbus off the hook. Neither shall I let the crew off the hook.

I would pray that current and future crews have a requirement to fly the jet in the alternate laws under strict supervision. Not depend upon simulators. Actually "feel" the plane and maybe even the buffet associated with an approach to stall.

Sorry if I have ranted.

why did the autopilot disengage ?

stalls and "deep" stalls, yet agin
 

Yep, Ventus, we've all heard about the "deep stall", and went thru the litany a thousand posts ago.

I even posted a graphic of the pitch moments of the Viper to show the problem, and no T-tail or downwash on the HS or....

We have looked at some unofficial charts of the Airbus and it does not appear to to have the classic deep stall combinations of downwash or lack of nose down pitch moments due to c.g. as with the Viper In other words, it appears that if the crew had applied nose down stick and maybe nose down trim that the jet would have "flown out" of the stall.

This is not unusual for many military fighters built since the late 60's. The hornet can duplicate the AF447 profile quite easily. To recover? let go of the back pressure and push the stick forward, just like a Cessna 150. Duhhhh?

Problem is recognition of the stall and the approach to stall on a well-designed, modern jet. Buffet can be confused with mach problems. No horrendous yaw excursions or abrupt pitch changes. The sucker will settle into a decent stall and not spin due to great yaw control laws and such. May have some roll tendencies, but not like +/- 20 or 30 degrees back and forth.

Apparently, the crew couldn't hear or disregarded the aural stall warning sounds. So I would think a simple stick "vibrator" could get the pilot's attention to look at the "new, improved" AoA indicator that should be installed. No timy bar graph, but something as big as speed and such. Red at top, yellow in middle and green at bottom. Pull and get into red, push and get into green. Real simple, and the Navy pilots have used the equivalent for 50 years when landing on the rolling deck of a carrier.

Whoa there, milady! For a start, the FMC/FCUs do not have a different set of reactions programmed based on the time of day for a given location. The specifications were laid down on the understanding that during daylight hours, the pilots have an outside visual reference that the computers not only do not have, but cannot comprehend. The design assumptions also factored in that the computers cannot match the human ability to problem-solve and compensate for situational changes in real-time.

What this boils down to is that in night-time IMC, the human pilots have less of an advantage over the computers than they do in daylight hours in terms of perception, but again, the human ability to problem solve "on the fly" is still better than that of any computer system of the vintage used in modern airliners - as a reminder :

Yes the computers have raw AoA information, which right now the pilots do not (this may change). However, I believe there are still too many variables in play to build the kind of system you're suggesting using the available technology and still get it into a certifiable state.

Fundamentally, while I understand your desire to engineer a way out of this situation, I think following that path is well-intentioned, but misguided. History has shown that nature (and the human psyche in particular) can outwit the best efforts of engineers almost every time.

hy gums and other real captains, who will test the simple side-window-wool-yaw-string in the real world of a jet?

http://www.dg-flugzeugbau.de/uploads...aden-4.jpg.jpghttp://www.dg-flugzeugbau.de/uploads...aden-4.jpg.jpg

yaw and AoA indicators
 

Yeah, Grity, if you could see the AoA string sucker, then you might/could use it! Night could be a problem.

We had a "yaw string" on the T-33, and that sucker worked up to 400 knots or so. Couldn't see it at night, but in daylight it helped one to learn to coordinate rudder with aileron.

A thorough training curriculum seems best recommendation from the accident board at this time, IMHO. Real planes at real conditions and with an experienced instructor. More value than with any simulator ever built.

I also want to take exploit this post to challenge one contributor that asserts the best way to stop on a slick runway is to watch the speed indications on the gauges. Beam me up! If I hit the brakes and I don't "feel" some effect, but "feel" I am actually going faster, then I don't need to look at some steenkeeeng gauge. I know that I am sliding on the ice or water. If anti-skid is working, I'll see some effect, and feel it as well. I'll guarantee most pilots here can sense the lack of decelleration faster than the airspeed/groundspeed gauge can reflect. The same applies to when a good crosswind is present when rolling out on a slick runway. Ain't no gauge invented except a HUD with a good flight path vector that is still working with weight-on-wheels that shows you that you are sliding off the runway. You look out the windshield and feel your skid. Simply holding a heading won't help.

On the other hand, relying too much, if at all, on your human senses while in bad weather most often leads to disaster. Gotta trust the instruments ( except 'bus airspeed in icing conditions). Our human sensors are great for detecting initial body rates, but degrade very quickly after a few seconds. Our human gee sensing is fairly close to what a machine sensor would detect, but that is not good for survival after the initial pitch input on the controls. It simply lets you know that the plane is reacting to your initial input. After that you had better trust the instruments.

Interested non-pilot observer here. I've read much of the AF447 threads here and on !!!!!!!!!!!!!!, and was fascinated by this accident when it first occurred.

One thing struck me though in the last thread here. In post 1346 in thread 5, "xcitation" brought up airbus manual specs stating that during high speed protection the flight computer adds "positive nose up g demand to the sidestick order." I would like to know, definitively: would such a computer-added input be included in the input traces sent to the FDR? If so, it seems possible there was a logic error that caused added nose up g demand during an UAS situation, and that nose up was included in the recorded data from the sidestick. In that case, the PF may not have been actually holding stick back input, and there would be no way to tell from the ADR traces.

I would like assurance that the input data traces from the FDR are raw inputs, and are never altered at all by the computer, in any situation. If they can be altered, then the PF's input traces are useless, because it could be PF error, or it could be computer error that is indistinguishable from PF error.

loxosceles;
The parameter for side stick position reports the side stick position, unmodified by any other inputs.

A slight confusion may occur if one considers that, for example, an aileron parameter will indicate the position of that surface, as controlled by the FCPCs [flight control primary computers] which are controlled in turn either by the side stick in manual flight or the EFCS [electronic flight control system] in autoflight. But the parameter still indicates actual "position" of the control surface.

Aircraft system, aircraft state and environmental parameters' design and mode of operating are thoroughly understood such that any untoward behaviours of a system are almost certainly going to be known. This was evident in the QF72 pitch incident.

Fine posts, gums, thank you.
IIRC there is the opinion that the aircraft could have been recovered from the stall, but opinions have varied regarding the altitude from which recovery could have been made. From what has been said, the elevators remained effective throughout the descent.

If someone who knows has the time and patience, could they explain what actions would be necessary for the crew to get the AP back and what dynamic state the a/c must be in for the AP to capture control ? Reason for asking is that before the 'details' became known I rather expected to find the crew heads-down dealing with the computers but this seems not to have been any sort of factor.

Chu Chu, with a wry grin I note that in this case the meatware proved faulty, probably for the same reason, faulty or incomplete programming, as the software might fail. I think that's an interesting if off beat way to look at the problem.

- I am equally disturbed that you are 'disturbed':)

What EXACTLY do you propose a pilot should do for those 'few seconds' when all is 'WTF' confusion? What do you suggest that stall recovery should be? 'By rote' reduce AoA or some other gums method involving what process? Nose high, speed falling - 'by rote' lower the nose, use power with care and bank if necessary or 'by gums' - let's see, I have 25deg nose up and 4000fpm up and speed decreasing through Vstall+20, so out with the spin-wheel/QRH and I need......................?

I'm afraid I cannot see your point, sir. Indeed, on the many occasions when I was, like you, 'outside the envelope' in my miltary days it was the 'by rote' that saved me..

HN 39 asks, "Which computer?"

At the very least the wee little computer that drives the FDR surely knows. If it knows then its source can also route that data where ever else it is needed.

I guess the general idea is that the pilots are as smart as the programmers/procedure writers, and therefore can fill in any holes on the spot. I'm sure that hasn't actually been the case since the Wright Brothers. But maybe the AF 447 pilots could have filled in the particular hole here if they'd been better equipped.

plan A, then B, then C, then...
 

Sorry, BOAC, I worded my concern poorly.

You are spot on as far as the initial procedure and then "plan B" and so forth. That process has certainly saved many of us here. Lest anyone here think otherwise, I fully support your position.

I was trying to point out to some folks that simply executing the tried and proven procedures/techniques may not be enough to recover from some "upsets" or cope with unusual system malfunctions. In other words, there are a very few conditions that are not covered by the known procedures. The two incidents that strike home are Sully's ditch and the Sioux City DC-10 landing attempt. After their initial actions, and not getting results, both crews went on to new territory and did not sit there for 3 minutes doing the same thing.

Hope that makes my position clear.

I first used "ROTE" as a pejorative; and to expand, 'rote' (the word) is not in and of itself unhelpful. As JD-EE eloquently puts it, 'the meatware had a software glitch'.

In America, 'rote learning' is seen as dispassionate, and insensate. Unfortunately, in a cultural setting, a word frequently conjurs all manner of misunderstanding, here, what confuses is the unsaid.

The "clipped" sense of 'rote' means more or less, "Instead of using your thinker".

Common usage is, well, common.

Rote.

In this misunderstanding here, perhaps an opportunity to close the consensus gap.

ROTE is 'bitchin'. ROTE is 'sick'. ROTE is 'memory items', for purposes here?

Language, so boring w/o it. 'Fly'.


gums. that is it, in suede. It is the 'Between' SOPS, and (UAS Drill), and Sully's test flight (w/o the brief), that the solution lies.

It is a no-man's land, a Maginot Line of suspicion, ignorance, and Pride, with globs of ego in there as well.

Take one of our engineer friends for a hop in your family model, and see if they grok what it can be like, flying with one's hair on fire.

Time is GOD's way of making certain everything does not happen at once.

'Transition' is what we do, or DIE. "I have the Controls' hmmm.......

really? because........

I suppose you are referring to the FDIU (flight data interface unit).
It's barely a 'computer'... the French term 'ordinateur' would be better.
It doesn't 'know' anything, and it doesn't 'think', it just converts and formats the multiple original AC and DC signals and digital info to a single formatted digital data stream (ARINC 717) which is then recorded by the FDR.
The link below is litle more than advertising, but may give you a few hints.
Teledyne FDIU

PJ2 this is in re: your following POST (don't ask me).......

(your #553)

Nothing personal, and certain to be flamed as PARSE.

They did not ADAPT, they CREATED. Adapt means to conform, and I am sure that is not what one meant, because in that sense it is remarkably disrespectful to some extremely talented people.

Creation is what is at stake here. Mostly Man destroys, the rest ADAPT, and the brilliant CREATE.

That is the essence of thus entire kerfuffle. Shall we CREATE, OR ADAPT?

ADAPTATION is the default, To create is to control. Automation is the ultimate adaptation, and clearly, there is a point of view at work here.

gums;
...and the British Airways B747 Flight 9 encounter with volcanic ash at Jakarta. Your point is well taken. In other words, these crews knew their aircraft and flew it. If something didn't work, they adapted through knowledge and experience.

Sorry if I seem to bracket one.

Automation is an adaptive environment, by definition. The upside is that man created the environment, for once. Then he fell immediately into what is demeaning, an adaptive posture.

On the one hand brilliantly creating his own environment, "Can you imagine?". Then, dumbly acquiescing into its power.

One has suggested Human Factors is the proper venue for this discussion, there you go.

are you shure you have a side window "yaw string" on the T-33?, you had it in the middle!?!, god for control not to much side slide...
but the side window yaw string is not for the side slide he is a good AoA indicator!, and I am shure it is easy possible to enlight it at night..... just open the window like nico and hang it out ....
http://www.spox.com/de/sport/formel1...co-hut-514.jpg