tobias118118 be carefull, your CRM instructor appears to have spooky tendencies. Anything he tells you is most probably false.

I gather that the same equipment will be used to search much of the area that was not covered during Phase 3.

Seemingly Very Relevant to AF447......
 

Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2011-0029; Directorate Identifier 2010-NM-279-AD; Amendment 39-16583; AD 2011-02-09]
Airworthiness Directives; Airbus Model A330-200 Series Airplanes; Model A330-300 Series Airplanes; Model A340-200 Series Airplanes; and Model A340-300 Series Airplanes
When there are significant differences between all airspeed sources, the flight controls of an Airbus A330 or A340 aeroplane will revert to alternate law, the autopilot (AP) and the auto-thrust (A/THR) automatically disconnect, and the Flight Directors (FD) bars are automatically removed.
It has been identified that, after such an event, if two airspeed sources become similar while still erroneous, the flight guidance computers will:
–Display FD bars again, and
–Enable autopilot and auto-thrust re-engagement
However, in some cases, the autopilot orders may be inappropriate, such as possible abrupt pitch command.
* * * * *
The unsafe condition is the potential for abrupt pitch command which may lead to unexpected maneuvers of the airplane and cause injuries of the crew and passengers, as well as reduced controllability of the airplane, and increased pilot workload. This AD requires actions that are intended to address the unsafe condition described in the MCAI.

WeeWinkyWilly;

...and I note from the docket that the FAA considered it important enough to follow the EASA AD (with minor administrative changes), making it effective only 15 days from date of notification on 12 January 2011. Effective as of now.

Docket No. FAA-2011-0029 - a PDF file.

mm43

mm43

Unfortunatly, your link returns 404 error to me.

Try this link - works for me

regards,
HN39

HazelNuts39 & mm43

Now I've got it. Thank's a lot.

Best regards

Consider this from page 86 of BEA accident report on A-320, D-AXLA
Now assuming AF447 somehow departed controlled flight while in Normal Law while cruising on autopilot, does anyone see anything in the ACARS sequence that would preclude this type of scenario? (other than the vaunted Airbus protections). Loss of autopilot and autothrottle would be due to the ADR failures which would be caused by the departure from controlled flight.
The RTLU position equating to M 0.8/272 KT would then make sense.

Machinbird,

This is an interesting theorie !
@Bearfoil has also suggested this as a possible cause for the ADR disagree.
Technically that seems to be possible.

Looking more empirically at it, there have been multiple incidents with pitots freezing over, causing ADR disagree and subsequent disconnection of A/P and A/T.

However I'm not aware of any instance where an Airbus (or any other airliner for that matter) flying on A/P at cruise alt has ever all of a sudden developped such an attitude that would cause this assymetry.

Besides that also the RTLU setting would mean it had to stall/spin at M0,8.

The more likely connection to AF447 is that the pilots might have re-engaged the A/P to early and the A/P held the plane in a deep stall all the way down.
The intriguing part of this is that I was seriously wondering how you would deep stall a conventional tail airliner all the way down to FL 0.
You would probably have to pull the stick (or mis- trim it full nose-up) until the splash. When you are manually flying a fully mis- trimmed airplane it would feel/react strange. You should notice a very different aileron reaction at a stall AoA.
But if Otto's at the yoke and tells you everything is fine you might not notice it.

Machin - I don't think your scenario will hold because it depends on a departure from controlled flight to initiate and we have no reason to expect that in a normal cruise scenario? Surely to arrive in that situation in a/p cruise would require a sensor malfunction first?

Re the AD - at last some common-sense emerging - don't implicitly trust the software. It is not that good. Fly the aeroplane.

Hi Henra, BOAC.
I've been looking at what might have caused a dynamic (Oscillatory) departure from autopilot controlled flight and I think I have found two potential paths for that bad result:

• The first is multi-pitot freezing causing erroneous airspeed input to the flight control system. This has the potential to foul up the flight control computer calculations and could lead to erroneous control loop gains being applied.
• The second is an occurrence of hydraulic supply saturation causing control rate limiting of the flight control system.

The subject can get technical quickly, but for the simple explanation of the first condition look at the results from the X-31 pitot icing caused accident. My apologies for the over stated video presentation.
Aviation Video: X-31 Crash | Patrick's Aviation
A more factual report can be found here-X-31 Crash

The subject of hydraulic supply saturation and control rate limiting is a bit technical and is related to PIO causes (but cannot be called PIO since the automatics would be in control) however suppose AF447 flew into a vigorous Cb and the control surfaces began moving briskly to keep the aircraft upright. If total hydraulic usage exceeded pumping capacity + accumulator capacity, new non-linearities would be introduced into the control surface control loops. The control loops would develop phase lags and could even drive oscillations the wrong way! The triggering event could even be as simple as autothrottles commanding a power reduction.

To help you wrap your mind around this second concept, take a look at the following two links:

Fly-By-Wire A Primer for Aviation Accident Investigators
Pilot Induced Oscillation

So if this type of stall entry would break the airframe, we could pretty well conclude that that the two above scenarios couldn't happen since the aircraft appears to have impacted in an essentially intact condition.

Those with flight control design experience, test flying experience and related experience are particularly invited to join in.

Hi,

Read the ACARS and post again ...

Machinbird;
I respect your knowledge on this subject, but my reasoning doesn't support the theory, simply because each actuator is either in pilot input or auto mode, and positional feedback from the control surfaces should avoid the hysteresis problem alluded to.

Or are you suggesting that the "hunting" results in effective loss of control as the hydraulics "stall"?

Which ACARS Post?
 

jcjeant, which ACARS post? There are 2650 posts so far. :ugh:

Smilin Ed, he said "Read the ACARS and post again ..." Note the "and" in there. You must have missed it when reading it.

{^_-} (Sigh, getting old is not for the faint of heart or the terribly vain.)

Smilin_Ed;

You might find the link to the ACARS list in Post #1611 useful.

MM43
MM43, I will borrow from the subject of PIO since that situation is the closest approximation to what I am trying to say. I am not a flight control engineer, so the professionals can likely find some (hopefully) small problems with my analysis.

The case of the autopilot flying the aircraft is actually not as complex as that of a human flying the aircraft. A human can adopt any one of several thousand different control strategies. The autopilot can only adopt the strategy it is programmed for. As a result, from a design standpoint, it is much easier to identify control demands for autopilot flight than for direct human controlled flight. The possiblity of exceeding the hydraulic supply capability of the aircraft was undoubtedly addressed since the engineers could go through all their worst case situations and tradeoffs and have a reasonable assurance of proper control behavior.

For small control inputs at a low rate of change, a hydraulic actuator can keep up with the changing demand and position its control surface very accurately. This is linear behavior in that control response is directly proportional to control input and achieves the commanded position with minimal delay.

As the rate (frequency) and amplitude of control inputs increase, the control actuator has increasing difficulty in accurately achieving the commanded position and it takes longer for the actuator to achieve the new position until finally, it cannot since the signal has already reversed. This happens because at some point, the actuator is moving at its maximum possible speed as determined by its hydraulic control valve opening or by control rate limits built into the control system (to achieve predictable control performance).
Electrical engineers use a tool called a Bode Plot to graph out control system response to a constant amplitude sinusoidal input of varying frequency.

Below is a Bode Plot of a Low Pass electronic filter, an item with response characteristics similar to a hydraulic cylinder.
File:Bode Low-Pass.PNG - Wikipedia, the free encyclopedia
From the graph you can see that system response amplitude declines past some critical frequency (in this instance 100 Hz, but on an aircraft control probably more like 1 Hz).

At some higher frequency, there no useable control response available-the control just sits there and buzzes.

Meanwhile the phase lag of the response grows as frequency gets higher. If you consider the case of 95 degree phase lag, the response could be considered to consist of two components, one 90 degrees out of phase and one (albeit small) 180 degrees out of phase!

Flight control engineers can design adaptive features into their control designs for known features through clever use of integrators and differentiators and by filtering out critical undesirable frequencies from the feedback path, but they need a predictable basis for hydraulic cylinder performance. That basis is that normal hydraulic pressure is available. If hydraulic pressure surges up and down as various elements of the flight control system are actuated, the predictability of all the engineer’s control studies goes down the toilet. The controls will move in unpredictable non-linear ways and induce additional time lags. That is the thesis of the second pathway to loss of control.

This thesis cannot be proved with the presently available information. We will need the flight recorders to understand what happened. My intent is to merely point out another way that AF447 could have been lost.

It should be noted that control rate limiting is inherent in all mechanical actuators and can cause PIO under proper circumstances. Almost every Fly-By-Wire aircraft has had some PIO instances during its development and operational history.

Both pilots and autopilots do their job through closing the aircraft control feedback loop. Dynamic loss of control while on autopilot could be considered as a special case under the heading of PIO. Many of the principles are the same.

Good point !

I checked the sequence and indeed there seems to be no slot in the ACARS list where an A/P re- engagement could have taken place.
(Btw. I am assuming an A/P re- engagement would not appear in ACARS - am I right ?)

I thought maybe after 2:11 but at 2:13 was the PRIM1 / SEC1 fault.
That would disconnect it again and at least then the disconnection of A/P would appear in ACARS.

So I agree: you can skip that idea.

Machinburd:
Seems to me that an "inner loop" driving the control cylinder rate and/or position to the pilot/autopilot requested values would have to exist.

This would remove the influence of instantenous hydraulic preasure variations. ("surges up or down"

This is similar to using feedback around an op-amp to precisely set gain even though the raw gain of the amp may vary 10:1 or more.

If the available raw "gain" (hydraulic pressure) is too low then the inner loop will fail but that would represent either a fundamental design flaw/or hydraulic system failure.

I am not familiar with real world details (work in electronics not hydraulics) so welcome insight from those who do know.

Mea Culpa
 

Mea culpa.


MM43, thanks for the link.

Ed

You're right.
The "demand" to the innner loop (from the pilot or autopilot) is in terms of control surface position (angle), the feedback comes from a control surface position sensor.
Your analogy is wrong.... the hydraulic pressure does not equate to gain. To use your op-amp analogy, too low a hydraulic pressure would be similar to the supply voltage collapsing under load or the op amp output stage saturating.
Exactly.
Since we have a simpler explanation than hydraulic problems, I tend to apply Occams razor....
The transfer function for a electro-hydraulic actuator is a bit more complicated than a simple low-pass filter, but the suggestion of oscillations in the system is somewhat too far-fetched... and would indeed imply a fundamental design flaw.... The technology has been around too long, and is too well understood, for this to be a plausible cause, IMO.

CJ

Hi Christiaan,
In light of the many thousands hours of successful operation of the A330/340 on autopilot, it might not imply a design flaw, but instead the exceedance of an unpublished limitation.

Just like AA587 taught us to be careful with rudder inputs, perhaps the legacy of AF447 will be that there are other ways to 'break' the aircraft than causing structural damage. Depending on how the flight control laws are structured, it seems possible that extremely challenging weather might cause excessive use of the flight controls and hydraulic pressure depletion/interruption before actual structural failure could occur.

At present, everything I have read relating to PIO/APC events indicates that these events occur with cliff like suddenness. Usually there is a triggering event-a final straw that breaks the camel's back. Things like changing of flight control laws, changing pilot control strategies (e.g. rate based control technique rather than attitude), changes in aircraft configuration, changes in power,and changes in flight conditions are often culprits.

One cannot realistically deny that PIO events exist and they are not restricted to fighter aircraft. They have been experienced on well known transport aircraft such as: A320,A321, C-97, C-17, KC-135A, MD-11, B767, B777, and a number of bombers as well. Not all of these experiences have been in development, a number of them have occured during normal line flights.

Since we are talking about an aircraft (AF447) on autopilot not under pilot control in the moments leading up to its problem, we are no-longer talking about a strict PIO event possibility, but that is probably a weakness of the definition. When it comes to FBW aircraft, the control system is always in the loop except when you lose electric power or hydraulic effector power to the system.

My gut feeling is that Airbus engineers did a great job on their software design, but for an aircraft to suddenly lose control while on autopilot would imply a possible condition well outside of the norm-something like hydraulic supply induced rate limiting.

The A330 is not a naturally unstable aircraft, but it is a relaxed stability aircraft which is made to fly nicely by virtue of its flight control system. Anything that gets in the way of the flight control system's ability to control is bad, and anything that actually aggravates the control system's control has the potential to be downright tail over teacup dangerous. It has been said that you can make an unstable aircraft fly with fly by wire technology, and you can make a stable aircraft lose control using the same technology.

For the doubting Thomases, take a look at these two Youtube videos, and remember-it isn't the pilot's fault-it is an aircraft problem. PIO exists and it doesn't always happen with developmental aircraft.
YouTube - F22 Pilot Induced Oscillation (PIO)
YouTube - Saab JAS39 Gripen Crash 1993
On the second accident, note the wing rock before the departure.

Machinbird posted :

Interesting but when ? Certainly not initially at 02:10. But maybe at 02:13, when the FMGEC1 failure appeared, as determined by the AFS in a class 1 message. The AFS would only detect a fault if it was active. So by 02:13, the pilots thought it was over and the aircraft showed them the F/D bars, and they reengaged A/P with unintended consequences...

Strongly disagree, these auto-thingies losses are due to the Probe-Pitot failure at 02:10 which put the PRIMs in a special alternate law with ADR monitoring.

Read again the BEA report : a failure message will not appear twice. If A/P was lost at 02:10, reengaged at 02:13 and lost again, its subsequent disconnection will not show a second time on ACARS (since they are maintenance messages and not flight data monitoring messages)

Remember, the basic situation is faulty probes to scattered ADRs to alternate law. This UAS is routinely handled by all pilots in the sim and in reality. Nobody crashes from cruise level because of this alone.

However, voting logic, ADR selection, PRIM behaviour under manual alternate law as compared to their behaviour under A/P, all these are of the utmost relevance. The AD put forward by a poster a few days ago reveals a possible hazardous misbehaving of the A/P itself under certain ADR failures conditions. These conditions are such that the system as a whole deems appropriate to show F/D bars and allow A/P reengagement when it is unsafe to do so. This is extremely serious and so very close to our mystery here.

Svarin
Other than the BEA reports proposing pitot problems as a cause, what do you see in the ACARS sequence to confirm this. Have you considered that maybe BEA, careful and methodical as they are, didn't get it quite right?

Shoot down the concept of the entire ACARS sequence being caused by a departure at the beginning if you can, but do it with data. I am attempting to broaden the possibilities of how this accident happened. Why couldn't the ADR problems be a result of a departure from controlled flight?

Gust loads
 

I too find this scenario intriguing. It wouldn't break the airplane though, as shown in this graph.

BEA's second interim report mentions one UAS incident where peak loadfactor excursions of 0.2 and 1.9 g were recorded:What mainly speaks against this scenario is that nothing in the available meteorological data suggests an extremely violent gust: the cb was already decaying, its tops were descending and it was spreading out horizontally below tropopause.

Machinbird posted

Everything is possible but you will need a root cause for upset, for which there is no proof nor evidence. That is a gratuitous hypothesis, not Occam compliant at all.

Both FPVs got flagged early in the sequence, and that means both guys at the front just switched their FPVs on and found them flagged. FPV is pretty useless in an upset and is definitely not the first thing you will do then. Beginning of sequence is stable flight, only condition when FPV is useful.

FMGEC1 gets faulted by AFS late in the sequence, and that means AFS is active. Which means it got reengaged, because it dropped early in the sequence due to UAS. This again says 'stable flight'. Flight was stable until this fault at least.

Last but not least, the whole ADR clusterphukk is due to Probe-Pitot faults early in the sequence. There is enough evidence of these particular probes icing in cruise to make this a reasonable root cause. Of course, there is something else to turn a manageable UAS into a crash from FL350.

By differentiating these faults specific to our mystery from those where no crash occurred, one will have a clue as to this additionnal problem. May I humbly suggest this : WRG : ADIRU1 BUS ADR1-2 TO FCPC2, HARD. Yes, hard indeed...

The Autopilot's Autonomous disconnect has some instructive considerations. Long ago, in a discussion with PJ2 and Will Fraser, it was determined that excursion limits AP had programmed into it would cause a potentially unexpected disconnect, and a degradation of Flight Law.

Now this is known. Let us add to that possibility the existence of severe turbulence, with its downside of allowing "Out of Phase" reactions of the airframe to rapid excursions in Pitch, Roll and Yaw. The AP program allows 45 degrees in Roll and 13u, 9d in Pitch. At this point, there should be a discussion of whether it is wise to continue into turbulence in Autoflight. Not now.

How in essence shall we differentiate between out of synch airframe response and controls position? The AutoPilot is programmed by control position and airframe aspect. So is it correct to eliminate the possibility of Upset whilst in AutoPilot? No. Assume the 330 was close to upset, or at least Unusual attitude at drop out of AP.

Instead of poor stability with the AP engaged, the Pilots are confronted with no stability when it quits. Law is Alternate, and hand flying in turbulence with an airframe that is aerodynamically, busy, is the handful of Enchilada Will Fraser posted. Getting the "Feel" under such conditions is not duplicable in the sim. Whilst attempting to regain stable and level flight, sufficient disturbance of airflow about the sensors is certainly possible to create duff reads.

Perhaps the "Upset" was not an identifiable moment, but an in and out thing that was mitigated for a time by the pilots, until perhaps air loads passed the ultimates for a control load, or for aero flight. "Out of Phase" has an interesting relationship to AA587.

Hazelnuts39
I appreciate your efforts in answering the max g available question.
It certainly helps if one opens the graphic to see the whole thing.:}

Regarding the weather conditions:

The initial BEA report stated:
The second BEA report stated:
I am not sure we can make reliable conclusions about the level of turbulence AF447 may have encountered. It is probably highly relevant that AF447 was lost in an active area along the ITCZ, but whether the relevance is pitot icing or turbulence or both or even some other factor is unknown at this time. We can only wonder why they did not see the necessity of altering course as aircraft in front of and behind them did in the ITCZ portion of their routes.

Svarin, It may be a day or two before I get back to your response, but I appreciate the effort you have made to be explicit.

svarin
Hmmm, interesting. Maybe I was too quick to dismiss the idea of an attempted re- connection of the A/P

Still it would have to be rather late in the chain of events, but then I'm not sure we can really conclude that they didn't re- engage it.

@jcjeant:
Are there elements in the ACARS which allow us to draw a definite conclusion that it didn't happen ?

Hello
Why? That the question.

Why the vessel had not altered her course and crossed convective zone at Salpu WP ?

Was there anybody alive in the aircraft before 02:00z ?
(I am sorry, but I don't remember exactly if ACARS messages proved that human actions had been done).

Why autopsies report is classified?

Machinbird;
The above is a good précis of the conundrum we are left with.

We know that AF447 tried 3 times to log on to DAKAR ADS-CPDLC but was rejected due to DAKAR not holding a flight plan - only a virtual one. The last time was at 0200z (DAKAR recorded 0201z) and I suspect that some discussion then took place between both pilots as to how to sort the problem. This distraction (by both) could well have resulted in failure to see anything significant on the WX radar right ahead. At this stage the radar tilt would need to be max down for them to see the Cb cell that was rising at 4,000ft/min right ahead. A few seconds at the most was all that it took for the latent heat of the super-cooled water vapour in the Cb the a/c penetrated at about 0209z, to condense and freeze over the pitot tube ports.

The GS over the period from 0200z to 0210z was 463KT, a reduction of only 1KT from the previous 10 minute period, and I suspect that the a/c had been proceeding in light to moderate chop. However, penetration into an active Cb cell took place shortly before 02:09:30z and the a/c probably pitched up violently and rolled to port as all hell started to break out in the cockpit.

I would go as far as stating that M0.82 was being maintained, though CAS dropped slightly in the chop, and was effectively recorded at M0.80 (272 +/-2 KCAS) by the RTLU as ADRs disagree, reversion to Alternate Law and both A/P and A/THR disconnecting. The 3NM deviation west of track occurred after the reversion to Alternate Law.

Distraction is not a great way to commence recovery from an upset.

A problem I have with the above scenario, is a "chicken & egg" one. Did the ADRs disagree due to Pitot induced UAS due to icing, or side-slip/yaw errors from an external physically induced upset?

No, I doubt if control loop oscillations, PIO or otherwise played any part in what took place. But why and how an otherwise undamaged aircraft (to the best of our knowledge) was delivered to the sea surface is the real conundrum.

NeoFit;
The following ACARS messages are relevant:-

2:11:00 WRN/WN0906010210 228300106FLAG ON CAPT PFD FD
2:11:15 WRN/WN0906010210 228301106FLAG ON F/O PFD FD

- which indicate that those pages were selected by the crew.

The reason for the outcome lies deep below the Equatorial North Atlantic.

Yet another hypothesis?
 

From BEA's Second Interim Report on AF447: The accident during flight QF72 was caused by an as yet unidentified fault in one ADIRU, which produced 'spikes' in multiple parameter output signals, in particular that of angle of attack. There is indeed no basis for assuming a similar fault in flight AF447.

On the other hand, there was no anomaly in the way the flight control computers reacted to the faulty AoA signal: the response to a 'high AoA' signal was apparently 'as designed'. As described in the ATSB report, that response was the simultaneous activation of two effects: the high AoA protection (alpha prot) nose-down elevator command of 4 degrees and the high Mach anti pitch-up compensation of 6 degrees. The 10 degrees of elevator movement resulted in the airplane pitching to 8.4 degrees nose-down and a negative normal acceleration of 0.8 g. From the ATSB first Interim Report: I doubt if an updraft would cause the airplane to pitch up. The immediate effect of an updraft is to increase the AoA, as shown in the graph I posted in #2664. Since the airplane is aerodynamically stable, it tends to return to the AoA for which it is trimmed, i.e. pitch down. Perhaps more important is how the systems respond in an updraft. The A/P, if engaged, will command pitch down to regain the commanded altitude. Stall warning occurs at an AoA of about 4 degrees (in alternate law). I wonder at what AoA the two effects observed in QF72 would occur. The yellow triangle in my graph at about 5 deg indicates 'buffet onset', which is also 'alpha max', corresponding to Vs1g at 1 g. Is this where 'alpha prot' attains it maximum authority? Should BEA look more closely than ATSB has done into the AoA that triggers the 'anti pitch-up' command?

Suppose that all this happened just prior to the loss of airspeed data, how would the pilot(s) react?

HN39;

Your excellent LF + AOA + Gust Velocity graph has got me thinking about the potential density/temperature of the contents of a rapidy rising Cb cell. I included the hypothetical figure of 4,000 ft/min (67fps) in my previous post, knowing that there is evidence that this rate can even be exceeded. Add in the "brick-wall effect" of the different air-mass and there is something worth considering. Is there not?

I am of the opinion (right or wrong) that evidence of a highly convective air-mass in the ITCZ, during the period in question, can't be completely ruled out. Satellite imagery for 0215z was actually scanned at 0208z over the area we are looking at, and the likelihood of a Cb burst can't be totally dismissed.

I’m sorry. A potential root cause was proposed-a dynamic departure from controlled flight with two potential pathways for that to happen. I would not have suggested that the ADR problems might have resulted from a departure at the beginning of the ACARS sequence otherwise. There is also no absolute proof for the older BEA hypothesis either. I will say that the dynamic departure fits some of the observed facts better: The RTLU position, and the fact that on at least 3 cabin crew seats, no one was occupying them at impact. A dynamic departure would be rather violent-probably 3 half cycles.

Quote:

---

Svarin-Both FPVs got flagged early in the sequence, and that means both guys at the front just switched their FPVs on and found them flagged. FPV is pretty useless in an upset and is definitely not the first thing you will do then. Beginning of sequence is stable flight, only condition when FPV is useful.

---

Bear with me, lets see what BEA says with reference to these. (I’m a steam gage guy, so I’ve not had an opportunity to use this type equipment.)

Lets look at messages relating to the PFDs (courtesy of MM43)

2:10:29
WRN/WN090601 0210 228300206FLAG ON CAPT PFD SPD LIMIT
2:10:41
WRN/WN090601 0210[228301206FLAG ON F/O PFD SPD LIMIT

Quote:

---

Meaning: This message indicates the unavailability of the FMGEC’s
characteristic speed calculation function

---

2:11:00
WRN/WN090601]0210 28300106FLAG ON CAPT PFD FD
2:11:15
WRN/WN090601 0210 228301106FLAG ON F/O PFD FD

Quote:

---

Meaning: This message indicates the Flight Director function is selected and unavailable.

---

2:12:10
WRN/WN090601 0211 341200106FLAG ON CAPT PFD FPV
2:12:16
WRN/WN090601 0211 341201106FLAG ON F/O PFD FPV

Quote:

---

This message indicates that the flight path vector FPV) function is selected but unavailable. In order to lose completely this function, which is elaborated by IRs in a way that is compatible with the CFR, one of the following three conditions must be met for each ADR:
barometric vertical speed higher, as an absolute value, than 20,000 ft/min,
true air speed higher than 599 kt,
measured calibrated airspeed lower than 60 kt.
Once the operating conditions are satisfied again, the FPVs reappear on the PFD (if TRK/FPA mode is still selected).

---

Looks like the Flight director was already engaged at the beginning of the sequence. Do you guys use the FPV(bird) enroute too? If so, it could have been engaged at the beginning of the sequence but wasn't 'squawked' until the rejection criterea were met in the second correlation window. Maybe AF447 started down like a safe at that point? Then again maybe it was just airspeed effects caused by the departure.

2:14:20
FLR/FR090601 0213 22833406AFS 1,,,,,,,FMGEC1(1CA1),INTERMITTENT

Quote:

---

This message cannot be the trace of a reset which, in particular, excludes the possibility of a manual shutdown. This message could be the consequence of inconsistency between the two channels in the FMGEC (COM and MON). Such an inconsistency could be the consequence of erratic input parameter values.
In any event, the effects of such a message could only be the disengagement of automatic systems, whose associated cockpit effect messages had already been transmitted at 2 h 10. The “INTERMITTENT” nature of the message means that the problem lasted for less than 2.5 seconds.

---

Quote:

---

Svarin-Last but not least, the whole ADR clusterphukk is due to Probe-Pitot faults early in the sequence. There is enough evidence of these particular probes icing in cruise to make this a reasonable root cause. Of course, there is something else to turn a manageable UAS into a crash from FL350.[/font]

---

Like MM43-I too wonder, is the ADR problem the chicken or the egg? We will need the black boxes to figure this one out reliably.

Any chance that we can discuss more about the search now that it will resume this month?

I'm hopeful that they find something now. They have to!

mm43;

The buoyancy of rising air is due to it being lighter (less dense) than its surroundings. It is about 3 degrees C warmer than the atmosphere at FL350 (based on figure 11 of Tim Vasques' analysis), but the pressure is the same. For one cell to develop significantly higher gust velocity than its neighbors, I think it must either get its air from a hotter source on the surface, or the surrounding atmosphere must be cooler than elswhere. The higher velocity would result in more 'overshoot', which would show up as lower temperature of the cloud tops in satellite IR imagery.

regards,
HN39

Bobman84;

The French Secretary of State for Transport, Thierry Mariani, and the Director of the Office of Investigations and Analysis (BEA), Jean-Paul Troadec, will meet tomorrow with the families of victims of the Air France flight AF447 disaster. They are expected to give the families a presentation on details of the new Phase 4 search location, according to a statement by the Department of Ecology.

The "Alucia" is the support vessel to be used by the REMUS AUV team from the Woods Hole Oceanographic Institution for the deployment of two AUVs provided by the Waitt Institute. The vessel has been moored in Seattle and recently (2011-01-30) undertook a short sea trial on Puget Sound, and is currently moored near the sea-plane base on the SE side of Lake Union. She is expected to depart Seattle in a few days time to proceed into the Gulf of Mexico via the Panama Canal.

Le Figaro has reported some details of the Phase 4 search. The Google translation is so bad I'll just link the original and hope that it is more accurate:

Le Figaro - France : Une ultime campagne fin mars pour retrouver l'AF*447*

gentlemen, with ref. the QF72 event and the ADIRU induced decent, and having experienced a similar fault in 738 and witnessed a AP induced roll as a result that was explained to me to be the fo's ADIRU going into test mode! Is it possible for a pitot blockage on AF447 to induce a similar fault at the commencement of the event.? Could it induce a failure to both ADIRU that may have presented to the pilots a extremely violent maneuver.?

BEA presentation (in French, 02/04/2011)
 

Hi gentlemen,
Some newly released documents in relation to the new search campain (phase IV):
La nouvelle campagne de recherches /
The New Undersea Search Campaign

http://www.bea.aero/fr/enquetes/vol....04.02.2011.pdf
too bad this document is not self-explanatory: would be interested to know how these (probability ?) maps are built, and which data are "integrated" ?

http://www.bea.aero/fr/enquetes/vol....ation.whoi.pdf
http://www.bea.aero/fr/enquetes/vol.af.447/remus3d.mp4
Nouvelle phase de localisation de l?épave du vol AF447 Rio?Paris de mars à juillet 2011 - Ministère du Développement durable
Jeff
http://www.bea.aero/fr/enquetes/vol....h.analysis.pdf
Ok, this last report by Metron provides all the answers.