G27, the pilots didn't follow the AB manual and if they were above obstacles not do the low altitude procedure but do the cruise prosedure of just hold present attitude for level flight and get out the UAS check list. They were new and inexperienced. They needed the only qualified pilot in the airplane to be in the cockpit but he was taking his break and they couldn't handle it. Hiring 300 hr pilots on automatic airplanes is not safe.

Flap flap flap:mad: - no they were not (for the fithtieth time). They were not '300hr' pilots (for the thirtieth time.. - they WERE 'qualified'.

For g27 - there was NO severe turb

Either of you read the report?
B44 page 29 et seq
G27 page 60

Give it a break?

This sidestick visibility thing is all well and good but I do not understand why the cpt didn't at least ASK the pf what he was doing never mind instruct him as to control inputs. There were enough pax behind him, situation didn't need one more.

Every rotation is done in direct law, and any undesirable erratic movement would be immediately evident due the instantaneous response of the aircraft.

Did he try to trim up to the FULL stop of 14 degrees ... ?
If the pilot wanted to trim up, let him make such a silly thing himself, Please. We really don’t need any automation to do it for him.
If the guy had done it himself, I would not show up here to defend his action.

And nothing to compare with what would have been obtain in direct law in terms of ND movement and AoA reducing in order to achieve stall exit.

If you think you can get below 60 knots on elevators only, it is your call. What I want to see is the BEA calling the shot. That should be detailed already.

So we agree.
It was the duty of the BEA to make recommendations to Airbus to include in their documentation how the sidestick concept does not permit the same type of supervision allowed by more conventional flight control commands.

The crews operating the Airbus must be made aware of such characteristic.

That's something we can keep for later, but for now I could resume it that way : Do not write too much in the technical as the judiciary could be too well at ease to use it afterwards …

As soon as the captain is back, the stall warning quits. For him a stall has been properly exited. He has no clue the stall warning can quit for other reasons than a stall exit. The Airbus documentation makes absolutely no mention of anything like it, and on the contrary it is specified that a stall warning won’t stop before a stall is actually exited, which follows both regulation and logic.

This stall warning thing puts everything up side down for the captain ability to properly evaluate the situation.

What do you want him to instruct if he cannot make sense himself of the situation ?

But it is a remarkable that the captain would need to ask the PF what he was doing, just because the sidestick concept deprives him to naturally know about the inputs made on the flight control commands.

Interesting and neat report about AFR1896 (from the Moroccan investigation authority)
Only in french unfortunately
http://89.30.127.37/docspa/2011/f-xc...f-xc110808.pdf
The event is from last year
This show again a real problem at AF about CRM .. respect of the laws .. etc ...
Extracts (Google translator)

BOAC, for the 50th time, they were hired with low time and monitored Airbus autopilots for years until their actual piloting skills were required with no autopilot and they failed. They could not hand fly.

- I've heard tell a lot of pilots start with 'low time', and in the 21st Century where most of us live, they then monitor autopilots for years (including the AF447 Captain).

They were NOT 'new and inexperienced' - get your terminology right - unless, of course, you consider 10 years on AB, 39 SA route rotations and 6500 hrs 'new and inexperienced'?

It seems you may have dozed off for a decade or two. Exactly WHAT do you expect a crew to have as minimum 'experience'?

"They could not hand fly." That much is obvious, but I would add for accuracy "They could not hand fly an AB340 in Alt Law.". How they would have fared in a different a/c we will never know.

I guess this is a waste of time but in my 23,000 hrs my airline never required me to be on autopilot and monitor it 95 % of the time and only take off and some times land manually. I always hand flew enough to know I could do what the autopilot quit doing. These two couldn't and what they did by pulling up into a full stall shows what automation does if you don't maintain basic flying skills.

BOAC, you are wrong even though you have 10 times the posts I have. No pilot should depend on automation if he can't do it himself. Yes I am in the 21st Century too but letting automation make you a monitor and not handle a simple situation like they had, UAS, isn't the answer. If the automatic stuff quits it is no big deal unless you don't know how to fly.

I think whoever said (Ziegler) that Airbus could be controlled ( monitored ? ) by his concierge was right
He just forgot to say that it was the plane had to be configured on autopilot and normal law

@HazelNuts39
To emphasis CONFiture´s position: Elevator only reduced from full NU to 15° NU (time 02:12.46 and 02:13:55) after a significant time delay, whereas in direct law the elevators would have responded immidiately according to the SS position, meaning SS neutral, elevators neutral, SS Full ND (02:12:32, 02:13:40) elevators equivalent full ND. Just superimpose the SS command over the elevator position and the outcome is obvious.

RetiredF4;

Thanks for emphasizing Confiture's position. I was aware of that when I wrote my reply. But would a brisker response of the airplane have altered what the PF was trying to achieve? Have you considered why he briefly released his pull on the stick? I submit he did because the airplane pitched up when he increased thrust. Nothing indicates that he had any intention to get the nose down to an angle that would have unstalled the airplane. When the attitude reached 8 degrees and stopped increasing he started pulling again and kept pulling for over a minute. Yes, the airplane would probably have responded more briskly in direct law, but it is somewhat of a stretch to say that that would have changed everything.

To answer that question we would have to come to a conclusion, what PF tried to achieve firsthand. Neither BEA nor our efforts here come to a final result.

Several options had been discussed here, and can be grouped into the intentional climb and the unintentional climb. By that i refer mainly to the amount and intensity of the climb, not the climb as the opposite of the descent or the equivalent of an maintaining level. That the PF intended at least to correct the indicated altitude loss and the deviating pitch and VS should be agreed to. Everything else later on is not clear anymore.

If the climb in that intensity was intentional, then nothing would have influenced or changed the end result. But do we have ultimate proof of that theorie? I dont think so. When PNF told the PF to go down, he acknowledged to do so, he did not argue against the PNF, although he didn´t comply in deeds. Was he not willing to do so or was he not capable to do so (intention to do so was present, but the means to accomplish it were unsuitable)?

We know almost, that the manual flying expierience of the PF on the A330 was mainly accomplished during takeoff and landing. In T/O it´s afaik comparable to a direct law behaviour, and during landing phase when SS inputs are necessary close to ground it´s flare law. During flare law the PF is maintaining the trajectory by compensating the system induced ND force by a NU SS input, and to reduce the trajectory he just has to relax some of this NU SS input. The normal feeling on the SS from day to day flying therefore is holding some backpressure to maintain the flightpath during landing or to rotate and climb during T/O. The necessity of ND SS input and the required amount of ND SS input in normal daily operation therefore differed grossly to that one needed to correct this unintentional climb.

Additionally in day to day flying the roll channel doesn´t need much attention, except when a change of direction is desired, but otherwise the aircraft is stable in bank. PF was occupied by getting the wings back to level and maintaining them there, with roll law in direct a task he was not used to do. He might have associated the prooblems in achieving the correct pitch with the deviations in changing bank angles.

My position was from the beginning and still is, that the initial climb in the recorded intensity and duration was unitentional due to lack of manual handling at altitude and in degraded law. That PF was more occupied by roll control than pitch control, the last one may be doing by feel like he was used to during landing phase in flare mode. His corrective action to the announced and acknowledged deviation from altitude and pitch targets was ineffective from the beginning, leading only to a little decrease of VS without correcting the main problem, the beginning trajectory through the propulsion ceiling and the lift ceiling. Selecting TOGA in honour of the stall warning 2 made those inadequate amounts of SS relaxing useless, increased the pitch even more and led to the final stall.

From that point on the crew was helpless, as they did not know what brought them into this situation, what that situation actually was and therefore denied them the insight, what actions would bring them out of this situation. Therefore the SS inputs in that phase after the stall are no pointer to the initial intent.

In this assumed unintentional sequence the mentioned points by CONFiture are more than valid.

Thankfully the other F-4 guy (Franzl) has more time to post than I do, but I'm in full agreement with his analysis.

Full nose up after the stall, was simply an attempt to stabilize the aircraft's pitch attitude by a pilot who didn't understand WTF was happening.

There is sufficient reason to attribute the initial nose up leading to the stall as coming from the roll instability leading to inadvertent nose up inputs and the tendency of the aircraft's pitch channel to mathematically integrate those inputs. (For those who did not take calculus, it means add them all together). When did the initial nose up occur? Answer: When PF was fighting the roll problem the hardest. Did he have time to formulate a strategy of setting a nose up attitude? I doubt it. His computing power had to be focused on the roll problem.

Why doesn't the aircraft stop trimming in Alt2 Law when approaching the stall like it does in Normal Law?

More than likely, the engineers couldn't figure out a reliable way to do it. With stall AOA a function of Mach and gross weight/configuration, they didn't know how to make the Mach correction without airspeed inputs. They really should re-examine this more closely.

1. You can likely make a fairly good Mach approximation from inertial data. With that data, altitude data, and a safety factor, they could stop the trim from running up to the limits.
2. By considering alternate sensors for determining a stall state, they could probably stop trim from running up despite what would seem to be reasonable AOA at lower altitudes. What happens to the airflow over a wing during a stall anyway? Don't you think we can make a sensor to detect that state? I do.

A tendency to pull rather than push, combined with a concern for overspeed, in direct law as in alternate law, that sums it up nicely.

RetiredF4
The BEA report includes a exaggerated number of
Probably
Likely
If
Maybe
In the technical and human factors sections
It is rare to see a report containing so many conditional , uncertainties and inaccuracies while investigators have all the records (CVR-FDR) in perfect condition and many visual ( material - physical ) evidences
How aviation safety can be enhanced with the findings and recommendations originating from :
Probably
Likely
If
Maybe
That I do not know ...

Good analysis Retired and 'bird.

Without a "brain recording" we shall never know why the pilot kept pulling back. And I don't agree with 'bird about roll PIO and such. May have been there, but not to any serious influence versus the constant back stick.

If there is one good thing about the 'bus and our primitive system in the Viper, it was that HAL would use every control surface available to achieve the trimmed gee ( ours could be trimmed, but the 'bus was one gee all the time, corrected for pitch attitude). So simply relaxing the stick pressure would let HAL do what he was supposed to, allowing you to figure out what the hell was going on.

Another poster provided an excellent discussion of AoA WRT mach and altitude and such. But I am personally here to tell you that our primitive system handled the problem really well. We never exceeded the AoA limits while hard maneuvering, and the only way we got into a true "deep stall" was to hold a high pitch attitude as our energy decayed faster than the control system could get the nose down. Sound familiar?

Gotta go. Dodging hurricane in Florida.

Addendum:

It still distrubs me to see some pilots here that don't seem to understand how their jet flies. The new jets, with all the augmentation and such, may appear to be real easy to fly. Then you look into all the control laws and such and see what HAL is doing.

What do you do when HAL gives up?

I can't find one commercial jet with FBW or basic/advanced augmentation that doesn't fly like we old dinosaurs were used to.

As several here have pointed out, the 'bus is a basic "direct law" until well up in the air or in the "flare" ( not sure what the flare mode does, but whatthehell).

Ours was "direct" until weight off wheels. Then it was blended AoA, pitch rate and gee command until gear was fully up. Worked for me, and thousands of fighter pilots that have flown the jet since 1973.

I have a lot more confidence as a SLF after reading some of the "war stories" here from the professional pilots than I had three years ago. But make no mistake! If I am on board and you are the PF/PIC/AC or whatever, I shall be back there analyzing every move you make, heh heh.

Huzah
 

The Peanut Gallery heartily endorses the views of Misters F4 and Birds.

:D:D:D:D:D

EEG for all pilots? A horrible idea whose time may have come.

:E

Hi Gums,
I agree. He may have been attempting to out climb the CB in front of him - I have heard of other pilots who would attempt to fly over the top of a CB rather than through it despite being far to close to their ceiling.

At Night? Wasn't the CB pretty much behind him and off to starboard by the time the pitots froze up? (assuming the 12 degree turn to port was reasonable).

It is virtually impossible to understand how an Airbus flies when all you have for training material is FCOM's - and when the first rule says an Airbus flies like any other airplane.

Re: A320

Quote:

---

The only way my instructor could force Dir Law left us with no roll control spoilers, slow ailerons, and resulted in an extremely unresponsive airplane.

---

FYI TTex & CONF:

1. A330 with only one SEC FCC available (other FCC pb's off):

One pair of roll control spoilers (depends on which SEC) and one set of ailerons

(During full SS roll input, down going aileron only deflects about ½ way, the up going aileron goes full deflection.)


2. A330 in ALT2 roll direct as a result of triple ADR disagree (ALT2B?):

Two pair of roll control spoilers and one set of ailerons

(During full SS roll input, NEITHER aileron deflects as much as they do with only one SEC.)


It's no T-38, but 'responsiveness', it appears, is in the eye of the ‘respondee’.

Thank you guys for bringing this stuff up.

Most here know that the idea behind any close examination of any accident, this one in particular, is learning and hopefully prevention. I think the conversation regarding important factors such as intention, willingness, capacity (of both airplane and pilot) are especially valuable contributions to an understanding of what happened and perhaps a bit about why.

Some comments regarding the sidestick, apropos franzl's and Machinbird's comments:

The THS is manually set prior to takeoff. On takeoff, the sidestick is held slightly ND until 100kts at which point it is neutralized. It is moved back to initiate rotation, usually about half-way or a little less, depending upon CG. Sometimes the rotation rate feels as though it requires checking-forward on the SS but the FCOM warns against this and one maintains sidestick position until the climb is established.

As described the takeoff is done in direct law with pitch normal law gradually blended in within 8 seconds of pitch > 8deg.

Once the initial climb pitch attitude is established, pressure on the stick is relaxed. In fact, speaking technically only, one can let go the stick and the airplane will remain in the last selected pitch and bank attitudes. Sometimes that is a reasonable way of avoiding stirring the pot, as the airplane doesn't need any input if it is at the intended attitudes. In other words, no back-pressure is required to sustain the takeoff pitch attitude.

One can fly a SID with small, "squeezed" stick inputs for roll and especially for pitch, (only because tiny changes are all that are required for speed control). Even in turbulence, that is all that is required, because in normal law, everybody out there on the wing is busy maintaining the last selected attitude and stirring the stick only adds to the busy-ness without much effect.

The airplane can be flown to cruise altitude and, again technically speaking if planned in RVSM airspace, in cruise in normal fashion. At high altitudes one is always gentle with any transport and not just "Airbus", due to reduced damping of the thinner air. (Many here know this already...I'm being thorough, not pedantic!)

The airplane can be flown in turbulence, even heavy turbulence, (moderate, not severe - which I have never experienced). One keeps inputs small to avoid stress but other than avoiding small (and I emphasize momentary), inputs due to turbulence the aircraft is as straightforward to fly as any I have flown.

Descent is still 1g flight of course and the airplane can be flown from ToD to landing, and I often did this for the A320, less so for the A340/A330 but only due to long-haul (fatigue) issues and STAR complexities. Again, no stick input is required in this phase.

On approach, the usual small movements to counter slight changes in pitch and bank are normal. To alleviate any impression that NU stick is somehow needed in the approach phase, there is no "back-stick" required until 50' when the AFS feeds in a slight ND bias to give the feel of a conventional flare. Pitch direct law is gradually fed in beginning at 100' while roll remains in flight (normal law) mode until the pitch is < 2.5deg.

In terms of a subtle bias towards "pull" vice "push" due to AFS laws in various flight phases, I have to observe that the required operation of the stick as described coupled with my own experience would not cause a bias either way. The control laws do not engender this sense that one must "pull" most of the time - the notion just doesn't apply.

Unless we know what was intended, I think the notion of "intention" has no "correct" application here in examining what occurred in the first 30 seconds after the UAS event. Clearly, we can intend something with all our being and still be wrong. "Intent" can be informed by knowledge, training and experience, or it may not be, yet one may fully "intend" an action based upon incorrect assumptions, mistaken understandings or shortcomings in knowledge or experience. To me, this is an important part of examining the crew interactions. Willingness to accept another's interventions in such circumstances will be based upon the strength of intent (one's interpretation of what is wrong), and not always (reliably) upon knowledge. CRM is designed to counter the natural unwillingness to let go of one's own assumptions to adopt, (perhaps initially on faith alone), another's interpretation of what is happening. We have all been in situations when we know damn well that we are right, until we aren't, and we may even surprise ourselves that it was possible to be wrong.

Applying a steady, not just a momentary NU control input to a transport aircraft at cruise altitude to a 10deg pitch attitude is counter to all intuition, training and knowledge yet there it is, applied to the point of stall. Why?

What was the basis of the individual intentions which initially overcame and subsequently replaced an understanding of a number of fundamental aeronautical principles such as energy management, high altitude flight, aircraft performance and operational principles of SOPs and CRM? What was more powerful than these?

Post-stall, there are contributions from the airplane which led, perhaps inevitably, to further confusion but in the first moments nothing from the airplane indicated that a sharp and then sustained pull-up was the correct solution to a particular flight problem.

The rapidity with which situational awareness was lost and not regained is also an important area of learning.

These are some of the thoughts that occurred as I read and re-read through HN39's, franzl's, gums', Machinbird's & CONF iture's contributions highlighting the challenges of understanding what really happened.

As ever, I remain convinced this accident had its beginnings with loss of a/p. We think we know better, but we do not. We assume PF knew right away the conditions, I suggest neither did. A/P loss due turbulence happens, and the 330 will remain in Normal Law. This would explain his cavalier attitude with Pitch, and focus on a newly twitchy roll axis.

We need to be careful about assuming things that have no direct evidence to support, and cognizant of possibilities that do not rest on a fundamental understanding of the recorded events. They had nil access whatsoever to records, none. They had their senses, we think, and what is left can be explained by any combination of cues and data that can be imagined.... It is common here, for some to base a condemnation of the crew on a single fact, and then assume truth by asking "Why"? I submit that is absurd... It is possible PF assumed NL until PNF announced Alternate Law. That is sixteen seconds of NU. NU that may have resulted from an erroneous, though forgivable, assumption of his, which thoroughly would explain his "negligent" back stick...

Thank you for your contribution, PJ2.

You explain the handling of the SS ion the different phases of the flight, and i have no reason to think otherwise. But do we know, what the procedure for hand flying the A330 on long haul flights is with AF and how much practice in the real aircraft that left outside the T/O and landing regime? When do they take over in the landing phase? When established on final no input is needed until flare mode activates, correct? As you describe and as i understand the NZ law, no stick input is required if no change of flight path is intended. Can we talk about flying manual in this case?

Imho no, it is changing flightpath manual instead of pushing buttons or turning knobs, but that´s it. Bank angle compensation acounts for no need to make any pitch adjustment when turning and autothrottle takes care of the energy management . The FBW concept as implemented here reduces the necessity for pilot input to one single axis operation concept. There is no necessity to manage all three axis of the aircraft and the energy at the same time with elevators, ailerons, rudder and throttles at the same time, meaning with manual inputs trained in years of expierience. It´s reduced to "point and let go, the system will take care of the rest ". Wether you do it with SS , a yoke or the knop on the dash board is no longer important. It´s a nobrainer.

When AF447 dumped AP, ATHR, normal law and protections together with the speed indication in the blink of a second, the PF was forced to use strategies he was no longer trained for. No system was taking care of roll when he concentrated on pitch, no autothrust was taking care of the energy management, and no bank angle protection available to stabilize the pitch during roll.

Let´s look at a different thing, which keeps me thinking about:

We know, that the aircraft maintains stick free 1g, and that SS commands a change of g blended with pitch rate starting below 210 knots. In a newspaper article from the early A320 flights i remeber, that the ratio is 50/50 at 150 Knots. The speed responsible used for this changeover was faulty, down to 60 knots which would equal nearly a pure pitch rate change. But the aircraft was traveling still at over 230 knots in the regime where only g command should be present. I could not find any reference from where we could draw a conclusion, wether this different SS command would have influenced the outcome of any SS order. There is reason, that this changeover takes place in the low speed regime, what influence does it create wehen this changeover is taking place when the airframe is still above the change over regime in degraded mode?

The assumption, that the PF initiated and sustained that climb intentionally disregarding all basic principles of flight, busting assigned FL, disregarding CRM and not anouncing his intentions neither to the PNF nor later to the captain explains all following events. It´s an easy solution (just change the pilot everything else is fine), but it´s based on thin or even no evidence.

Hi franzl;

Thoughtful response, thank you. The points are eminently worth discussing, and for the time being concluding who's theory is right is less important than the discussion!

By all means, and what you say in your next paragraph, (. . . "It's a no-brainer"), is in my view largely though not exclusively true for the present standard of training and expectations, a clear risk which is now being widely discussed, examined in the many conference topics since AF447 and how has the attention of at least the US and European regulators, (in fact AW&ST provided articles in August, 1989 and January/February 1995 discussing these aspects in automation development).
I think your comment may be accurate in this case and this case may, among a couple of others, be a harbinger of such a developing trend. However, the Air Caraibe event and thirty-odd others which occurred prior to and also after AF447 do represent counter-examples to the "no longer trained for" point because to a greater or lesser degree, these were successfully completed flights. I don't believe such circumstances would leave the majority of crews in a situation they were no longer trained for, at least, quite frankly, I hope not because this wasn't in and of itself and all else being equal, (I recall, and take your interesting point regarding the pitch/flight path item), a serious emergency, (as in loss of pressurization, hydraulics, electrical power generation, engine thrust or engine disintegration, etc). If we consult JACDEC or Aviation Herald we can read about a number of incidents, events and near-accidents in which crews addressed them as trained and which did not result in loss of control or loss of the aircraft.
The evidence is in the absences of an expected standard initial response to an abnormality, which, I will add, is a point which thus far has yet to be discussed and countered.

To my knowledge and experience as an airline pilot there are no circumstances, save for perhaps extremely rare and dire events, in which SOPs, CRM and discipline take a back seat. These responses are proven, primary responses, heavily-emphasized and trained in airline operations and to deviate from them requires significant operational factors.

No such factors or events prior to the stall warning are in evidence. If the airplane pitches up due to some anomaly, one tries to get it back down to stable flight, period, yet the inputs are mostly NU; one does not permit the airplane to do what it will, not, at least, without vigourously trying to counter what it is doing. If one doesn't counter the anomaly, the evidence is that one agrees with what the airplane is doing and it should "do more". So no, this is not an "easy solution" which dismisses this crew out of hand. This is an extremely difficult solution to come to terms with because it is human factors-based and one must be very careful to examine such factors while avoiding the narrow focus of "blame". Finding out "why", despite some commentary to the contrary, is the way to prevent this kind of accident. If there are training and standards issues, that needs to be examined as do priorities in terms of autoflight and manual flying it is to be discovered first through this unfortunately-blunt process.

- and I would dearly like to know why, but as I said months ago, I fear we are 'dancing on the head of a pin' here since the reaction of this crew was so out of the ordinary as to render, in my opinion, any logical approach to this accident of no value, except in re-focussing at least AF's attitude to basic flying skills in their crews and some vital changes to AB software and philosophy.

That not-with-standing, the dissection of the FBW system has been of great interest and my hearty thanks to all who have taken the trouble to expound.

Perhaps the final report answers your question, at least part of it? At any rate, the response of the FCS and the airplane to longitudinal sidestick commands is recorded in the traces of elevator/THS and pitch attitude.

Safely at FL350 maintaining attitude would have saved them. They did the low level terrain profile of 15 degrees nose up and toga power. You can't do that at FL350. They screwed up and I think everybody knows it. They were both autopilot monitors, not hands on pilots.

HazelNuts39

"In alternate 2 law, the longitudinal control law remains a load factor law and the lateral control law is a direct law. In the specific case of alternate 2B law, some coefficients used in the longitudinal flight control law become speed-independent and are set for the maximum speed for the aeroplane configuration (330 kt in clean configuration). This hardly modifies the behaviour of the aeroplane in comparison to normal law, but can nevertheless induce an unusual response dynamic when the aeroplane has an abnormally low speed for the configuration."

You have said before you believed the "unusual response" might be sluggishness. As an aside, could it be the reverse? Could the Pitch rate be extremely high, if the coefficients are computed for Indicated speed, when it is erroneous? Would that not impart an emphatically increased authority to the elevators, relative to pilots inputs? Especially if the actual velocity was .80 Mach?

If the responses were sluggish, would that not possibly explain PF's dogged pursuit of some G? Might he have been seeking the twitchiness in Pitch that he found in Roll? If he thought the aircraft was unresponsive in Pitch, would he not command as much as he could get? If he sussed sluggish, and got no immediate "response" would he be tempted to trade rate for continuation of input?

He could not have seen AoA, and he would be using the horizon as his guide, which although high, did not jive with his sensation of load? Much of the g post 1.65 and the reduction to 1200 fpm from 7000fpm was less than one, was he flying knowing that his Pitch was high, but negating it to some extent because he did not truly believe the Pitch jived with the loading? Nose high and descending without a Stall Warning would communicate that one of them was wrong. Especially without Airspeed.

Did he choose to follow the wrong cue? The lack of gee over the horizon?

Dynamic pressure coefficients, et al
 

Hey, Lyman! The coefficients are most likely the "gains", as we FBW pukes call them.

The basic gains are mostly for determining the amount of control surface movement and the rates they move. They are also modified according to configutation, so gear down they will be generally lower in movement or rate, but it depends on the jet. In the Viper, the movement was higher, but the rate was lower.

When our pitot-static system went FUBAR we went to "Standby Gains", which were about 140 -160 knots gear down and 300+ knots CAS gear up!! Surprisingly, almost the same as the 'bus on the high end. Hmmmmm.... Remember that we still had the gee and rate limits, but it still worked well, and we were used to high gee maneuvering.

Bottomline is that the 'bus gains actually provide a kinder, gentler handling when in the back-up mode. Not skittish or overly sensitive.

My personal beef is the lack of AoA inputs beyond the warnings. I could live with basic AoA limits ( "protections") throught the envelop unless in "direct", and then clear warning indications that I was gonna stall the sucker.

Thread... Please DIE!:E

Hi gums....

You say.... "Bottomline is that the 'bus gains actually provide a kinder, gentler handling when in the back-up mode. Not skittish or overly sensitive."

I think it is possible our PF noticed the above in Pitch, and when he determined his inputs could not effect rate, as in Roll direct, he traded rate for "holding" aft stick, (persistence). It would be the first time he experienced different "Law" in two axes. In selecting Roll as his preferred (Direct), he may have decided his efforts would have more effect in Pitch if held. A mistake, surely, but he had no experience flying by seeking g, another first time only time. Til then, the aircraft had always done it.

Bear in mind, most everything that happened after a/p loss was a first time event in the aircraft, along with a deluge of alerts. He appeared terrified of G<1.

His training had been nothing like yours, not his fault. I don't think it is equitable to slam him for trying what he thought would work. Not that you are, I think you get what he was up against. The sobering thought is that he was one of thousands who might have the same responses to unexpected gremlins.

Respect,

The sobering thought is that he was one of thousands who might have the same responses to unexpected gremlins.

.. and that's why this series of threads is so important ... sorry, Alber Ratman

We must always remember how to fly by attitude and thrust, no matter how automatic the airplane is. If we don't we are not really pilots. We are programmers of autopilots. Don't let it happen to you.

Basic philosophy
 

Nice concept, Bubs.

Although my IP had explained a lot about AoA and lift and such, on my first flights he taught me to use pitch attitude looking at parts of the canopy rails and such. Hold an attitude at a power setting and watch airspeed. Slowing down? Lower the nose a bit, and vice versa.

There are few planes in the commercial arena that will suffer catastrophic failure if you simply "hold what ya got" if you have any warnings except terrain collision. Sure, complete loss of power such as Sully had requires keeping airspeed for maneuvering and such by lowering the nose. But even my LEF emergency only required that I keep doing what I was already doing ( lots of sidestick pressure to keep roll under control and yaw trim would come later).

Another pilot here has already commented that the nifty flight director bars helped to get on course or intercept the ILS or...... But I can tell you that when I got my interceptor assignment outta pilot training that the Air Defense Command liked those of us that had flown the old T-33. No fancy ADI or steering or such when on instruments. "Primitive" would be a good description. So they let us fly target missions and such after only a single checkride. The T-38 troops had to wait until they were at their permanent assignments.

First jet I flew with the steering bars was the SLUF, and it was very "loose". Most of us did better using the raw data, heh heh. Years later I got to the Viper and no steering, just raw data( see my video of the LEF landing approach). Hmmmm.....

Somewhere in the aftermath of this tragedy, the powers that be must take a deep breath and implement better training. Ya think?

This seems to match with the FDR data where only INB Ailerons were solicited at a max deflection of 16 degrees out of 25, and spoilers 4 and 5.

After PRIM and SEC1 were turned OFF, only spoilers 4 remained active. I suppose the zipper shape for spoilers 5 and 6 show their inactivity related to PRIM and SEC1 status.

Another hit at the BEA :
Why no further comment on the PRIM and SEC1 episode, especially in regards to the human factor analysis ?
IMO, this one clearly indicates that the crew (or at least the PNF) lost faith in the aircraft, and probably thought they were facing a computer bogus, or a protection takeover.

CONFiture,

Can you expand on that? Switching off the PRIM came up right away, did it have to do with trying to get the bird?

"We have tried everything"...

I have sensed the presence of workarounds in this cockpit, how are you meaning "lost faith in the a/c"? How does the suspicion of Prot take over fit in?

BEA have left all out but the rudiments, what are they doing? Do you consider the zipper to be generic, or specific to each instrument, mode or system?

Hi all.


AF 447.

In this terrible disaster of flight, if you allow I would want to remember to you the following points:


1) the strong vertical movements of the air inside the cumulinembo CB.

2) with pitot-tube clogged (iced) the airspeed instrument then acts like an altimeter.


What do you think?

From 4 Aug 2011 I read and reread-reread all your messages about A330 disaster.