Has there been further consideration of the ACARS messages and are they now fully understood. Will the final report deal with this?

for the caracteristic of the SS the stronger spring must have space for the first 6.5 mm, (your nice picture is not exact in this detail) if the weaker spring was broken then the neutral aerea is between +/- 6 deg of handle deflektion.....

there are two dual cartridges so the risk will be seldom x seldom...... what is very seldom....

grity, For springs not operating in the yield range, the lifetime is very long, in the millions of operations. For a dual failure under this condition, the probabilities suggest that the first failure must not be observed, and the system continues to be operated with a single cartridge providing feel. If this case is valid, then the probabilities of two broken springs on the same flight move into the possible range.

We have to ask the 'Bus maintainers and pilots, the likelihood of a single failure not being written up within a reasonable period of time ~ 6 months max.

Pilots might like a softer feel to the spring cartridge and might not write it up.

Maintainers have periodic checks that they do on everything. The question is not how often this is checked, but how often is it checked using a method capable of reliably detecting a partial spring failure.

I know of no Airbus pilot that would take any chance at all when considering aircraft control. Unless an Airbus pilot is totally inept, he/she is acutely aware of the tenuous link we have to life and won't take any chances. I would put the chances of a pilot ignoring a soft stick at exactly zero.

:eek:

You got that right. There's medication available now. :}

Time 2 10 07

• VS is not zero but minus 500 fpm
• The altitude shows 200 feet below the assigned flight level
• The attitude is below the horizon

Every reason for the PF to initially pull.

Time 2 10 08
Bizarely AP has already disconnected but FD are still displaying, probably for a nose up command.

Time 2 10 17
After dissapearing, they are back, but for a few seconds only, in ALT CRZ*
The altitude is very close to 35000 feet so the FD must indicate a sharp nose down command if the VS is still at a positive 4000 fpm.

Time 2 10 26
Again FD are back, is it for a 10 seconds period, but it must be in VS mode this time.

Before studying anything in that direction, we need to see the Vertical mode trace and analyze how and if the FD may have influenced the PF inputs.

CONF iture
An altitude 200 feet below the assigned level is not in itself major reason for concern and it doesn't look like the PF's reaction to this situation was appropriate. I am also interested as to where you derive your nose down attitude from. There is no evidence that the FD was feeding the pilot false information and you are just introducing another red herring.

BEA IR3 page 88
02:10:00 Pitch attitude decreases from 1.8° to 0° in 3 seconds.
Also visible in the FDR readout on BEA IR3 page 111

You shouldn´t be that fast with red herring.


In FL350 a 0° pitch can be considered a nose down attitude, as the aircraft won´t maintain level flight anymore. The crew had to react, that it ended in an unexplainable overrreaction is another thing.

Even better on page 42.

HN39,

You said C * :
This means that the feedback of the control law changes at a speed close to 200 KT (not mentioned by AIRBUS in our reports, to my knowledge).
To lower speeds the pitch rate is used in the feedback; at high speeds feedback is using G. :p
When the speed is correct, with 3 correct ADR, the smoothing of the two feedback goes well.

But in the AF447, speed selected for that smoothing is either false, or switching from one value to the average of two dissimilar, then the feedback leaps and bounds in the loop! :E
Therefore we must expect APC / PIO (aircraft pilot coupling / pilot induced oscillation) !
1. The initial PIO pointed to by Machinbird may be born of such a discontinuity. :}
2. Other APC have been born then at the option of pitot failures (curve of the three speeds is very discontinuous) creating "non-surmountable" (CVR) instabilities in pitch and loss of control. :E
3. The very rapid oscillations of the parameters from 02:11:40 may perhaps be explained as well. We never got to overcome the possible output of the stall and we never discussed these oscillations that trouble me since I've seen these oscillations.:{

A slight loss in indicated altitude seems to accompany a UAS event.

From the Air Caraïbe A330 UAS Report written by Hugh Houang, January 12, 2008
Translation:
At 22:22:59, a very rapid decrease of CAS, Mach and altitude (Mach correction) is recorded. These parameters respectively decrease to 85kts from 273kts, M.26 from M.80 and 34.700ft from 35.000ft.
. . . .

At 22:24:25, the CAS raises from 111kts to 275kts, Mach returns to M.80 and altitude abruptly raises from 34.200ft to 34.500ft.

My knowledge of these things is limited to the bits I picked off this thread. My understanding is that throughout the speed range the feedback is the response of the airplane in terms of pitch rate and Nz. At low speed the pitch rate is dominant, and at high speeds the Nz is dominant, but both components are present all the time. The response of the airplane in terms of q and Nz is not affected by errors in the measured airspeed.

It was established some time back that the 367 foot difference in recorded altitude was an anomaly. I buy that, but remember the crew had no knowledge of that.

I'll leave it to others to review the data. For the record, the PITCH was accurate, at '0', the altitude was displayed as 200 feet low, and the speed? The Roll correction was met with 'twitchy' response, the airmass was turbulent, the cockpit noise was unknown (sic), etc. Weather, Dark, Surprise, mind how you go.

I'll simply remind everyone that you were not there, and I venture to say that the upset found its beginning in the initial handoff. Look at some of the actual (inertial) vertical data points, remember the conditions, and try to avoid judgment of the outcome based on the initial record......


re: IA What he said, V V V V V V

PJ2;

The 300 ft drop in indicated altitude is explained in IR#2, para. 1.6.11.6 Consequences of a drop in the measured total pressure (p.49). At cruise AoA the pressure at the static port is slightly higher than the true ambient pressure. The measured static pressure is therefore corrected by a term that is proportional to airspeed-squared (or Mach^2). That correction is essentially lost when the pitot pressure drops to a low value.

The TAT/SAT/Mach anomaly is demonstrated very clearly in this ATSB FDR traces graphic of an UAS event to VH-EBA on 29 October 2009.

http://oi48.tinypic.com/2urtro8.jpg

Click on the image to see full size graphic.

please do not set the possibility of any mechanical mistake to exactly zero, as long as no one know "why he had pulled in this way"

mayby it is 1/100000 but truly not zero

grity, Tex was not addressing the likelihood of actual failure, merely in his opinion, he thought an Airbus pilot, if he knew, would write it up, immediately, every time.....

HN39;

Thanks very much for the information - much appreciated.

CONF iture,

From a pilot's p.o.v I think the theory that the reduction in indicated altitude as an initiating source for the immediate pull on the stick by the PF is reasonable in and of itself, however it does not account for the destabilization of the flight path and rapid loss of control that follows. As for the theory of two pilots slavishly following their flight directors to the exclusion of all the raw data being presented, we may posit what we wish but it is not possible to draw any conclusions either way.

No conclusion at this time, but considering both AD + one OEB + the data, one must consider in priority what were indicating the FD when displayed. At this time I see far too little in the 3 IR on that subject … Also, I am still very much concerned we still have to be presented the vertical mode trace ?

Regarding the initial maneuver, it is not only the reduction in indicated altitude, but also a negative VS + an unusual low pitch for a cruising FL.

Blindly following the FD is not a thing to do, but I am afraid signs here could let us think that’s possibly what happened.

@PJ2

however it does not account for the destabilization of the flight path and rapid loss of control that follows.

No. I have virtually always used it is a beginning, however. To connect the initial manual responses to what happened, may not be so inexplicable, with patience, and an objective and sincere attempt to put one's self in the cockpit.

I have. I am not ATPL, but a pilot, and what I feel when I get to Bonin's seat scares the !!!! out of me... I can make it real. I have sat mesmerized while some one on the right tells me something I need to do, and I nodded, and did not do it.... I have gotten behind, in turbulence and inadvertent IMC in a VFR ship, and nearly crapped my pants. I praise God for the quality of the aircraft I have flown, and the forgiving nature built into most a/c.