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AF 447 Thread No. 7

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Old 28th Mar 2012, 01:07
  #1021 (permalink)  
 
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It depends on which page you read!

I checked page 10 as Lyman cited. Here is the pertinent paragraph as copied and pasted by yrs truly:

At 2 h 12 min 02, the PF said, “I have no more displays, and the PNF “we have no valid
indications”. At that moment, the thrust levers were in the IDLE detent and the engines’ N1’s
were at 55%. Around fifteen seconds later, the PF made pitch-down inputs. In the following
moments, the angle of attack decreased, the speeds became valid again and the stall
warning triggered again.


It can be seen that on the chart posted by jcjeant (page 94), that time point of 2:12:02 is not even mentioned.
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Old 28th Mar 2012, 01:16
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OC I posted the comments stand alone, because PJ2 had inferred that they did not exist; context comes with chronology, certainly, but we were talking two different time frames. I don't see the problem.

PF and PNF made those comments as Captain re-entered, and I would point out the lack of further discussion as remarkable. The a/c was LOC and dropping madly. The report is to blame for the disjointed and disconnected conversations, not I. Why don't the comments I quote show up with the comments jcjeant posts? Where is the chronology, the complete record?
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Old 28th Mar 2012, 01:20
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I rejoin the fray after PJ2 has broken silence, and A333Z continues to provide detailed diagrams and systems info. Attaboys all around. And I think some of the inputs from we non-commercial drivers have helped. At least I hope so.

While wondering what the final report will conclude, my personal feeling is it will come down to training and stall recognition/recovery by HUMANS, not the machine.

- From the data traces I see no extraordinary efforts by the crew to recover from a stall such as using flaps, spoilers, etc. In other words, I do not think the crew knew that the plane was fully stalled, and the control inputs do not reflect appropriate stall recovery techniques/procedures.

- I flew the Deuce ( F-102) early in my career and it had no obvious stall entry warnings or "feelings". All that happened was the jet began to descend rapidly ( sink rate) and it had exceptional directional stability. Seems the Concorde had similar flight characteristics.

Recovery was very easy. Move the stick forward/relax back pressure in order to reduce AoA . Additional power helped, but the underslung motors on the 'bus seem to induce a nose up moment versus the centerline motor of the Deuce. Same true for the Viper, and the thing would simply start to descend with full back stick pressure once it reached the design AoA. Unless that puppy was in a deep stall, then recovery was the same - lower the friggin' nose!

- While looking at the reports and data, I conclude that the 'bus is a very stable and well-designed jet. So a stall may not be easy to recognize, especially if the crew is trained that "you can't stall this airplane". FBW and "protections" for another time, another thread, IMHO. But it may come up in the final report.

So I will make my prediction that the final findings will conclude:

- Crew applied inappropriate control inputs for the existing flight condition when data was lost ( regardless of the failures of sensors and such)

- Flight instrument displays and aural warnings were confusing.

- Crew entered a stall and did not recognize the stall nor apply appropriate control inputs to recover. In other words, the plane did exactly what the crew was demanding.

- The report will demand better training and crew coordination during unusual flight conditions.

Am I way off base?
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Old 28th Mar 2012, 01:25
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PJ2

02:11:45 FLR/FR0906010210 27933406EFCS1 X2,EFCS2X,,,,,,FCPC2 (2CE2) /WRG:ADIRU1 BUS ADR1-2 TO FCPC2,HARD

Here we are again at WRG. Followed by loss of displays, as noted by the pilots seven seconds later. Comments? The time is the same as that when the Captain re-entered.

Last edited by Lyman; 28th Mar 2012 at 01:38.
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Old 28th Mar 2012, 01:37
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Sure seems like someone is intent on spinning the hamster wheel up to record speed.
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Old 28th Mar 2012, 01:52
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Lyman, re, "I don't see the problem." Nor do I, bearing in mind the broader question regarding the availability of the displays which I think is in keeping with the second of the three phases of this accident as outlined in IR3, (p72 - 76).

Re, "Here we are again at WRG. Followed by loss of displays. Comments?"

No, none.

There is nothing in the "WRG" indication in and of itself that is unarguable evidence for a loss of all displays.

Forgive me but we can go back and forth many times, as seen, and I've made my comments and asked my question.

I am entirely open to new information and would change my approach according to such new information but failing that I think it is not complicated pre-apogee, and post-apogee it is largely unpredictable (in the sense of citing cause > effect), in terms of human, aircraft and system performance. One must go where the available evidence leads, using one's experience, background and "sense of things".
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Old 28th Mar 2012, 01:55
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Cool

Hi,

Gums
- While looking at the reports and data, I conclude that the 'bus is a very stable and well-designed jet. So a stall may not be easy to recognize, especially if the crew is trained that "you can't stall this airplane". FBW and "protections" for another time, another thread, IMHO. But it may come up in the final report.
I repeat ...
You have no datas in the BEA report .. only cartoon graphics ...
For have a good idea of what was the actions of the pilots we need the FDR DATAS ! and accurate (sharp) graphics instead chalk drawings on a board like the BEA ones ...
Those will stop to a end the spinning wheel ....
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Old 28th Mar 2012, 02:10
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Well, Lyman,
I learned a long time ago, as a Metallurgical Engineer doing failure analysis, you don't have to look at everything at 10,000X to find the defect that caused the failure. Often, most failure analysis can be determined looking at things from a much broader perspective, 1X. Analysis of an airliner crash is nothing more than a failure analysis, crudely as it may seem in these terms. Honing in on flap & slat setting or spoiler activity is looking at the problem at 10,000X or greater magnification. You need to back off and look at AF447 at 1X, once again. The BEA has graciously given you a considerable amount of data to study and understand. It is what they knew to be factual at the time they released IR #3. Not every organization charged with determining the cause of an accident would provide what you have received as of now. So begin to look at what you received as fortunate rather than incomplete.

What you should be focused on is the 1X. It starts with this from the BEA IR#3:

The Look Ahead

Cloud mass reflectivity depends on the type of air mass and on the season. Cumulonimbus reflectivity is not the same in temperate regions and below the equator. An oceanic cumulonimbus reflects radar waves less than a continental cumulonimbus cloud of the same size and height.10

Gain, tilt and the ND scale enable pilots to adjust the weather radar. Gain defines the level ratio between the signal received and the signal emitted according to the distance of the echoes. The CAL position of the gain control sets radar sensitivity at the standard calibrated level of reflectivity. The equivalence in precipitation is thus associated with a colour of the echoes presented on the ND.

Adjusting the ND scale enables monitoring at varying distances of the aircraft.

Heavy precipitation that returns most of the radar signal may also hide another disturbed area situated behind.

Representation of the weather situation by crews is thus mainly linked to the use of the 3 setting parameters and their knowledge of radar, particularly of its limitations.

Onboard radar does not directly detect dangers to be avoided and has specific limitations which require active monitoring from the pilots and constant analysis of the images presented to limit the risk of underestimating the danger of the situation. It should be noted that, at the time of the accident, the presence of ice crystals at high altitude was not considered to be an objective danger and that crews were not made aware of this.

In cruise mode above 20,000 feet, a slight downwards adjustment of tilt, depending on the scale selected, is recommended so that the ground echoes only appear on the ND at the edge of the furthest distance circles. This method enables the simple and practical application of the height/tilt rule of equivalence providing the optimum tilt adjustment.

When pilots monitor the weather situation, gain can remain in CAL position. In the confirmed presence of storms and during their avoidance, a manual adjustment can be used for comparison with the CAL image.

A scale of 160 NM enables the change in the weather situation to be assessed and anticipate route changes. A scale of 80 NM is used for avoidance. Short scales must be periodically discontinued in order to observe distant weather conditions and to avoid an impasse amid the disturbances.

Red or magenta zones as well as fringe-shape echoes must in this way be by-passed from windward by regularly adjusting the tilt and the range. The avoidance decision must be taken before the echoes are at 40 NM.

The operator recommends avoiding flying less than 5,000 ft above or below a storm cell. It provides a formula for pilots to estimate the separation height between the top of a detected cell and the airplane. This formula uses the distance and the tilt points from which the zone echo disappears. Above 23,000 ft, it is recommended to fly more than 20 NM from these zones.
How did the AF447 flight crew manage their radar? Did they sense what was ahead?


The Beginning of The End

Neither of the two copilots formally identified the stall situation that the airplane was in, either via the aural warning, or by recognising the buffet, or by interpreting the high vertical speed and pitch attitude values. It should be noted that buffet is the only indication of the approach to stall at high altitude on other airplanes whose stall warning threshold does not vary with the Mach.

In the absence of relevant information from the copilots, reading the information available on the screens (pitch attitude, roll, thrust, vertical speed, altitude, etc...) was not sufficient in itself for the Captain to become rapidly aware of the airplane’s situation. He did not then ask questions that could have helped him to understand the sequence of events.

The stall warning lasted 54 seconds continuously, during which time neither of the copilots made any reference to it.

Despite several references to the altitude, which was falling, none of the three crew members seemed to be able to determine which information to rely on: for them, the pitch attitude, roll and thrust values could seem inconsistent with the vertical speed and altitude values.

The investigation brought to light weaknesses in the two copilots: the inappropriate inputs by the PF on the flight controls at high altitude were not noted by the PNF through an absence of effective surveillance of the flight path. The stall warning and the buffeting were not identified either. This was probably due to a lack of specific training, although in accordance with regulatory requirements. Manual airplane handling cannot be improvised and requires precision and measured inputs on the flight controls. There are other possible situations leading to autopilot disconnection for which only specific and regular training can provide the skills necessary to ensure the safety of the flight. Examination of their last training records and check rides made it clear that the copilots had not been trained for manual airplane handling of approach to stall and stall recovery at high altitude.

By the time the Captain returned to the flight deck, it was too late, unless he recognized the situation immediately, he didn't. What ever happened from there on was futile, there was no time given the situation.

So flaps, slats or spoilers , or not, they didn't make a difference when they left the flight envelope and were in the stall descending at 124 miles per hour without recognition of being in a stall situation. I would suggest you, one more time, read pages 87-101 of the BEA IR#3, carefully. You will see (read Pg. 94) they briefly deployed spoilers for 3 seconds before retracting them and it does show on the cartoons as jcjeant calls them. Look at the bigger picture, Training (lack thereof), knowing the airplane and rapid situation recognition.

As for the final report, I think you will be disappointed, not every little nit will be contained nor should it be, only the pertinent data.
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Old 28th Mar 2012, 02:28
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Cool

Hi,

Tubine_D
The BEA has graciously given you a considerable amount of data to study and understand. It is what they knew to be factual at the time they released IR #3
You can call this spinning wheel or any name but the BEA no released the DATA (listings) of the FDR ( it's what I call "a considerable amount of data" )
This was a early material available to publish ...
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Old 28th Mar 2012, 03:07
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PJ2 Turbine D Organfreak, Machinbird.

Howdy. It is an honor to be in such company, and I consider it my good fortune to be allowed to participate here. We all bring different skills, experience, and demeanor. I am a low time commercial pilot who had the good fortune of owning a small aviation business at one time. I am in awe of the quality of discourse here, and to any extent you have stayed is testimony to your patience, or masochism.

This is no ordinary wreck, it is a criminal investigation. Due negligece, and various other human shortcomings, 228 souls are dead. 447 transcends the usual, and while it is tragic, it is nothing to discard without several microscopes to hand. No one is well served by being too easily satisfied. I understand everyone's approach, and also the frustration of those who believe they know what happened. If anyone can direct me to the Court's website, I will say goodbye. Failing that, I hope you can understand MY frustration at any sign of "laissez faire".

"Standard of Care". "Duty of care". Without these, and what you all know of aviation, no one would fly. anywhere. Ever. My opinion? Air France should be shut down, and reorganized. The corporate culture there is largely to blame for the accident. How do I know? I don't have to know. They know. No one is innocent in this industry, bargains are struck daily, and competition is fierce.

It costs money to park equipment and rnr air sensors. Motive? Dough. Result? these dead souls. My family flies that airline from time to time, their people are wonderful, and their equipment is modern, and safe. Knuckleheads who think they are smart, and can game the odds, these are the enemy. You know them, and not only in aviation do they cost lives.

Hamster Wheel? Small price to pay, if the Truth is outed. Don't give up. Don't let the knuckleheads skulk away, to risk your family, next time.
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Old 28th Mar 2012, 06:59
  #1031 (permalink)  
 
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Man machine interface issue? "Stressing" Human Factors?

Hi,

gums:

The "global picture" analysis seems correct. 1X as Turbine D properly emphasized: IMHO, under "unusual flight conditions" you need:

1) Reliable System "outputs". In your second point you put "...confusing"

2) "Graceful Degradation" and "Fault tolerance" from the System. There are indications the crew lost important (System) outputs during the "long" trajectory from apogee to SL: 3) In your point #3 the "entering into the stall", "not recognition of it and lack of "correct perception" does not (could) suggest the need for a review of certain aspects of the "man machine interface"?

4) "Unusual flight conditions" were not partly derived from "UNUSUAL conditions" PF and PNF (clearly lacking proper training) were submitted from the environment outside and INSIDE the cockpit?

My comment on your question:

Am I way off base?
Is:

The "man machine interface" will be an important factor in this accident or the training, CRM, etc. should "compensate" it's (sometimes complex) characteristics?

PS

What i mean by "characteristics" is some "well known" issues observed in these "advanced flying Systems".

So a stall may not be easy to recognize, especially if the crew is trained that "you can't stall this airplane".
PS2

"Advanced flying Systems" currently uses "RIDICULOUS DESIGN" with respect to "air speed" anomalies (by non availability of adequate sensors) during transients (like occurred in this accident) . Still applying erroneously the very basic concept of Redundancy. And relied on (non properly trained) pilots to use "band aids" in (sometimes) "possible difficult situations" typical of daily commercial flights.

PS3

And I think some of the inputs from we non-commercial drivers have helped.
For sure!

PS4

Crew applied inappropriate control inputs
A fact!

Question:

In this case (a complex one) pilot (PF) error will be the cause? All "inputs" he received (before and during the flight) like training and System "outputs" will be considered important (for his actions)?
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Old 28th Mar 2012, 07:37
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Synergy

Hi,

PJ2:

The far more critical aspect of this accident is "Why?"


There are (yet) many (possible) and important reasons to answer "Why".

At present I think it is not complicated.
Please comment.




Old Carthusian:

Unfortunately it refuses to die.


Why (it refuses...)?

Last edited by RR_NDB; 28th Mar 2012 at 07:41. Reason: Put question mark
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Old 28th Mar 2012, 08:08
  #1033 (permalink)  
 
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RR NDB
The reference is to the non too disguised attempt by some to attribute the accident or parts of the accident to the machine and not the human, cultural, management and training issues. One, of course, welcomes a spirit of inquiry but one is forced to question why so many otherwise rational people are so excised by the possibility that the flight crew got things wrong and that this was the only reason for the crash. I am afraid that I keep coming back to the adage - we try to make the machine foolproof but God keeps on designing better fools (not that I think that the flight crew were fools, just that is the adage). No matter how well a machine is designed someone will find a way to evade it's safety features and wreck it. The man/machine interface strikes me as another red herring I'm afraid.
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Old 28th Mar 2012, 11:33
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Hi Old Carthusian,
One, of course, welcomes a spirit of inquiry but one is forced to question why so many otherwise rational people are so excised by the possibility that the flight crew got things wrong and that this was the only reason for the crash.
The Flight Crew Training Manual has this quote in Abnormal Attitudes Section:
"The effectiveness of fly-by-wire architecture, and the existence of control laws, eliminate the need for upset recovery maneuvers to be trained on protected Airbus aircraft."

I think that might be changed.
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Old 28th Mar 2012, 12:21
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I was talking to a commercial (bizjet) pilot at the weekend, who told me that sim training has changed considerably post 447. There is now much more on approach to stall/buffet (but not into stall), and emphasis on recovering controlled flight including nose down if that is what it takes, and not on minimum height loss only as it used to be.

Second hand, I know, but there must be some AB and other ATPLs here who can say if that is a general thing.

Last edited by chrisN; 28th Mar 2012 at 14:14.
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Old 28th Mar 2012, 13:05
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Originally Posted by PJ2
I think this because that is a significant operational emergency decision
It is part of FCOM SUPPLEMENTARY TECHNIQUES following an aural stall warning, nothing more nothing less :
If below 20000 feet and if in clean, select FLAP 1
Such action from the crew would be an indication on how they were or not understanding the situation.

as I mentioned, system behaviours in these circumstances are much less understood than in normal circumstances and, like the earlier examination and sorting out of the ACARS messages, a lot of permutations/combinations would have to be examined before a definitive sense of what was being displayed on the PFDs at any moment during the post-apogee phase.
That is why I would not rush to state that the CAS was the only parameter to momentarily disappear.

Originally Posted by HazelNuts39
I don't suppose you would be very disappointed if BEA doesn't publish all 1,300 parameters from the FDR? Those who claim BEA is withholding data will never give up.
For now the BEA is selective ... but the Judge is withholding data from the proceedings.
Have you heard anything to the contrary ?
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Old 28th Mar 2012, 16:31
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Cool

Hi,

BEA chalkboard graphics less FDR data is partial and inaccurate information
FDR data (listings) + sharp graphics are valuable information AFAIK and could reduce the field of speculation
I can understand that the full CVR will not be released to public for many obvious reasons .. but why not the FDR ?
What are the reasons ?
One "Why?" more ......

Last edited by jcjeant; 28th Mar 2012 at 16:45.
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Old 28th Mar 2012, 16:34
  #1038 (permalink)  
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Hello RR_NDB;

Originally Posted by RR_NDB 28th Mar 2012, 00:37 Post # 1033

PJ2:
Quote: The far more critical aspect of this accident is "Why?"
There are (yet) many (possible) and important reasons to answer "Why".
The context of the question, "why?" is Phase 2 (as stated in IR3) of this accident: Why the pitch-up and then the continued pitch-up post-apogee? So, yes, there are remaining many possible and important reasons in answer to the question, "Why?" in this context but there are also a number of explanations which are less probable as to why. The focus on aircraft system anomalies after entry into the full stall and descent will not answer the question regarding Phase 2. The extreme stress and confusion/cognitive dissonance indicated in Phase 3 resulting from aircraft/system behaviours that were inconsistent with the crews' view that they were still flying despite the stall warnings (crew comments in IR3 regarding "high speed") and the recurring stall warning and airspeed indications, likely contributed to the significantly-decreased chances of assessment of the problem and swiftly reducing opportunity for recovery.

Quote: At present I think it is not complicated.
Please comment.
Well, I have been commenting all along since last May up to these series of posts on why I think this is not complicated but I will try to make that uncomplicated!

First, "not complicated" doesn't mean that details of both human and aircraft behaviour are dismissed as sidebars or non-causal factors...not at all. But some theories and notions of what happened are more in accord with what we know and therefore more relevant than others which we have seen. It is not always easy to know when one is merely jamming a notion into the small box of known facts so that a theory fits a preconceived notion, or whether one is "on to something" and just needs to ask more questions.

But as more becomes known, one is able to parse such interesting activity and ideas and then tentatively set aside some notions and turn towards others which are more plausible, at least until something else comes along which hints or even proves that one might be off-base so that one can start again. It isn't a perfect way to do things but it works.

"Not complicated" here means, this is a loss-of-control accident which resulted from stalling the aircraft. Why did that happen?

That happened because the airplane was pitched up and held there until the stall. Why? This was done immediately, without announcement, standard crew coordination, (CRM) or following SOPs. Why? The PM made no interventions. Why? One simply never pitches a transport aircraft up to 10 to 15degrees at cruise altitude and holds it there because intuitively knows what will happen...a rapid loss of energy. We have to assume the PF was earnest in his response yet the response was not correct. Why?

Some details for this exact point would be the prior crew discussion regarding climbing and the FMGC MAX ALT message. That was a clear indication that the airplane was already very near its altitude limit in terms of available thrust to maintain cruise flight. Why go higher where the available thrust would not maintain level flight let alone a zoom-climb? That would be a detail. The climb happened versus not: Why?

In Phase 3 when the "stall, stall" with Master Warning and audible warnings were heard why was the stall warning not respected as per the UAS QRH checklist? A number of ideas have been posited and discussed and may explain this but the key point is, it happened, vice not. Why?

What is going to be very complicated is understanding the human dynamics and factors which led to certain behaviours and not others. We already know that training regimes, simulator scripts, awareness of high altitude flight dynamics and swept-wing transport behaviours as well as system behaviours are being taught everywhere but we may only be able to make guesses at the psychology of the flight deck in this accident and this is where we must be extremely cautious and respectful of the crew and of our lack of knowledge.
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Old 28th Mar 2012, 16:56
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Gratuitous Post #Billion

@PJ2:

Masterful summation.



(I'd hire this guy!)
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Old 28th Mar 2012, 17:08
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To characterize post apogee Pitch inputs as "mostly nose-Up" is not fair. The a/c wandered NU/ND between -3 and +17 several times.The co-pilot input ND several tmes. He had no ability to see the AoA, as we know. To constantly insert AoA in the record, knowing the pilots had no access to it, is dishonest on BEA's part. Again, several times the Nose was down well below cruise values, and continued to descend rapidly; increasing speed, and further disorienting the PF/PNF. It IS fair to ask "Why no push on the Stick to gain perhaps 20 degrees ND?"

It was PNF (LHS) who was doing the flying when the Captain entered and said "Er, what are you doing" LHS continued to fly during the initial phase of three pilot command. I can suggest that pilots reread the chronology on pp93-94 with a fair and objective viewpoint, and keep reminding yourself you have PITCH only, not AoA. It is quite clear none of the pilots had a clue as to where to put the nose, keep it, and pull out. STALL was not in the mix. And remember, the STALLWARN is WARN, not STALLED, necessarily. At one point, both sticks were to the stops, left, and the a/c was Rolled right 4 degrees, and when one stick relaxed, it immediately Rolled right to 7 degrees. I still think there was a problem with the airframe, Rudder/Lateral, that favored Right Roll, chronically.

I think it is reactionary to dismiss the possibilities of 'desperate' measures, taken by crew. Also to 'assume' 'most' displays were 'working'. If they had been, why can I not also say, "Then why the confusion on deck?" Alot of pointing, alot of statements, alot of confusion, and consternation. This includes instrumentation prior to STALL, why would that be excluded.

I would think that a fair position would be: "With so much confusion, how could the instruments possibly be working? There is no record of displays, just as there is no record of the pilots solutions. These have to be inferred, as CONFiture has pointed out in his response to PJ2. I am frankly more puzzled by the preStall record, not the utter LOC afterward. When there is no reason to say "He simply pulled up, we don't know why", then there is no reason to claim incompetence.

Especially when given the circumstances. The record of instrumentation and displays rests on the Pilot's verbal record. Relying on the DFDR to bolster an argument when no such data was available to the crew is simply dishonest. We were not there, yet so many make accustaions as if they were. And yet I am accused of Hamster Wheeling? I am suggesting the record is incomplete. WAY incomplete.
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