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Old 14th Jun 2009, 09:41
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for God's sake, get a life. (in reply to 4PW)

The Bus has been flying for years with very few incidents that have resulted in loss of life and/or the aircraft itself.

Everything man made has faults and the idea is we examine the faults to try and make sure they get fixed and don't happen again.

If you want to frighten yourself reading every AD that has ever been issued/is outstanding or everything that has gone wrong without explanation then you'd never get out of bed.

Quite frankly, with comments like yours, I'm amazed you're a pilot (or maybe you just fly the sims ?)
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Old 14th Jun 2009, 10:10
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On another point about composites, when I was at Airbus working on VTP structures we always used hot/wet testing (both heat and moisture degrade composite structural properties). I don't know about the fatigue work as I wasn't involved but I don't think it would have been done differently. Thats not the same as fluid getting into a sandwich structure, as with the rudder failures, which is a more serious problem.
Fatigue testing is usually done at room temperature ambient conditions with a LEF (Load Enhancement Factor) to account for hot/wet / cold conditions. LEF is usually around 15% for most composite structure.
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Old 14th Jun 2009, 10:10
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We have a lot of theories, a lot of speculations, some evidence. I am not going to speculate in any direction at all.
What is a little puzzling, at least in my view, there appears to be an "accumulation" of incidents with unreliable airspeed, instrument loss etc.

Did someone establish already the timeframe when these occurrences started to happen in more closer, time-related, manner?

Once this date is known (a rough approximate will do) the next question will be, what was changed in the AB system, and here I mean the electronic bits and pieces, the computers, the software, wiring etc; I also ask for the air system, the pitots, the static ports, the tubes, trapped water releases, all this sort of things.

Our flying offices are constantly "upgraded" to enhance safety; sometimes this implies even removing of items as they are not seen necessary anymore.

The reason I am asking all this, and some colleagues may have experienced the same over years, there are airplanes around which during design state had a certain recommended configuration for individual flight phases; after several "incidents" the once recommended procedure / setting / part was altered / prohibited or even removed.
Old 14th Jun 2009, 10:29
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Sorry for soundling like a broken record:

Does anybody know, if the AF A330s are equipped with the Backup Speed Scale (BUSS) package?

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Old 14th Jun 2009, 10:41
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Sunday Sum up - the story so far

Here's a thoughtful piece from Prof.Peter Ladkin:

A list of the 24 ACARS messages listed by Air France that were sent from AF 447 between 0210Z and 0214Z on 1 June, 2009, the last information received from the aircraft, was shown on the France 2 TV channel on Thursday June 4. This list, in which incomplete information was shown, was typed up and distributed on the Internet (one must beware of typographic errors in the various versions which I have seen). Thus people started to interpret the messages and inquire about their significance.

I take it that people know what “reading tea leaves” means? Fortune tellers would look at the pattern of leaves left in the cup after the tea had been drunk, and wondering what they say about the future. Similarly, people (including myself, here) have been looking at the (partial) ACARS messages shown on the TV, and have been wondering what they say about the past. I adduce the comparison to propose a healthy dose of scepticism about what one can validly conclude from the currently publicly-available information.

The messages were listed in the following order (omitting messages which consist of maintenance warnings). The four-digit numbers are the Joint Aircraft System/Component (JASC) code, which I interpret from the FAA JASC Table and Definitions Document from February 11, 2002, which is on-line.

* at 3.5 hours before the main events, a 3831 event. Something concerning waste disposal (38 is water and waste, and 3830 is the waste disposal system)

* at 0210, a 2210 event: AP off (22 is Auto Flight and 2210 is the Autopilot system)

* at 0210, a 2262 event (22 is Auto Flight; I have no code 2260)

* at 0210, a 2791 event, flight control switch to alternate law (27 is flight controls; I have no code 2790 or 2791)

* at 0210, two 2283 events, flags raised on CAP and FO Primary Flight Displays (PFD) (22 is Auto Flight, I have no code 2283)

* at 0210, a 2230 event, autothrust off (2230 is the auto throttle system)

* at 0210, a 3443 event, a TCAS problem (34 is navigation; 3443 is the Doppler system. The Doppler system here is used to measure relative motion of another body, in this case another aircraft, for TCAS).

* at 0210, two more 2283 PFD flags

* at 0210, a 2723 rudder travel limiter fault (27 is flight controls, 2720 is the rudder control system). At higher airspeeds, the rudder travel is limited by the Rudder Travel Limiter; far less movement is allowed than at lower airspeeds.

* at 0210, a 3411 event with EFCS 2, reported by EFCS1 (3411 is the pitot/static system. I understand that on these airplanes, the system is divided into the pitot subsystem and the static subsystem).

* at 0210, a 2793 event involving EFCS 1. (27 is flight controls. I understand from colleagues that, on the A330, 2793 is the Flight Control Primary Computer, FCPC, also designated PRIM)

* at 0211, a couple more 2283 PFD flags

* at 0212, a 3410 event. A disagreement between the air data units, the AD part of the ADIRU (34 is navigation; 3410 is flight environment data). An “ADR disagree” can only occur when one of the three ADIRUs has already been designated as faulty by the FCPC, and the two remaining ADIRUs yield discrepant readings (this information from the Aircraft Operating Manual of the A330)

* at 0212, a 3422 event in the standby flight instruments (ISIS) (34 is navigation, 3422 is directional gyro and indicators)

* at 0212, a 3412 event involving IR2, the inertial reference part of ADIRU2 (34 is navigation; 3412 is the outside air temperature sensor and indicator). Reported by IR1 and IR3 and EFCS1.

* at 0213, two 2790 (EFCS) events, FCPC 1 and Secondary FCC (FCSC) 1 faults (27 is flight control; I don’t have the 2790 designator)

* at 0213, a 2283 event, reported by FMGKC1 (22 is autoflight, I understand from colleagues that 2283 is the Flight Management and Guidance Computer, FMGC)

* at 0214 a 2131 event (21 is the air conditioning, 2131 is the cabin pressure controller).

What about the ordering of these messages? First of all, they are time-stamped by the minute, so that orders them into five groups (the 0210 messages, respectively 0211, 0212, 0213, 0214). What about a finer ordering? That is going to be much harder. We don’t know whether this listed order is the order in which the messages were received (but Air France can probably tell us that). We don’t know whether the order in which the messages were received were the order in which they were transmitted (but maybe there is something in the code that can tell us that). We don’t know whether the order in which they were transmitted is the order in which they were generated (maybe Airbus can say something about that, but there might also be some indeterminacy). And, finally, we don’t know whether the order in which they were generated is the order in which the events occurred (that may be hard even for the manufacturer to say, because the rates at which values are sampled are very different, depending on the system).

For the purposes of a speculative interpretation, let me assume here that the events occurred in the order listed above. I do caution that this is quite a significant, and not necessarily correct, assumption. Let me further assume that the messages are veridical. For example, that the “ADR disagree” message really does indicate that the FCPC has ignored air data input from one ADIRU and is judging that the air data input from the other two are not consistent with each other. How significant this assumption is depends on whether one is a sceptic or an optimist about the reliability of these highly complex programmable-electronic systems and one’s trust in their design.

So here goes. The AP went off and flight control went to alternate law. Flags pop up. Autothrust disconnects, something with TCAS and then two more flags. Rudder travel limiter has a problem and then something with the pitot-static system that the EFCS’s have problems with. Sometime over a minute later we are told that the air data from one ADIRU has been designated unreliable by the FCPC and the air data from the other two disagree. Then the laser ring gyro in the ISIS complains, as do the primary and secondary flight computers (these systems are duplicated: it is the number 1 units of each that are complaining), something happens with the FMGC, and then there is a cabin pressure warning.

Why might AP go off and flight control go to alternate law? One possibility is (1) you’re being severely shaken around, or (2) for some reason the AP couldn’t maintain altitude. Another possibility is that (3) there was a system problem. Then the autothrust (AT) goes off. That would happen if, for example, that auto flight systems cannot maintain stable air speed (AS) and altitude. I don’t know what the TCAS notification would signify. Then there is a rudder travel limiter fault. That device has AS as input, so maybe there is an issue with AS sensing. Then EFCS1 thinks EFCS2 has problems with pitot-static sensing. The pitot system colludes with the static system to measure AS, and the static system is also used to measure altitude. Then EFCS 1 complains about FCPC (I take it that would be FCPC 1, also known as PRIM 1). Then two of the three remaining air data units disagree and can’t reconcile (we don’t know when the first was voted out by the FCPC 1). At a similar time, the DG in the stand-by flight instrument system complains. At a similar time, the inertial reference part of ADIRU 2 is faulted by the other two. Then unspecified faults with FCPC1 and FCSC 1, but it’s not clear which system component is reporting those faults. Then another flight control issue, and finally the cabin pressure controller squeaks.

There are some patterns here. One pattern is there is a lot of stuff involved with AS and altitude, and at least one with the outside-air-temperature sensors. The commonality here is the pitot and static systems and their interaction. Then later comes the DG in ISIS, followed by IR2 being voted out and then FCPC and FCSC faults and cabin pressure.

What could be up with the P-S systems? One possibility is that they are getting all iced up. That would be why AP and AT think they can’t maintain altitude. That might also explain the outside-air-temperature probe complaint, if it were being iced also. But manufacturers and regulators know about ice; it must have been extraordinarily severe to overwhelm the sensor heating systems.

Another possibility that some have mooted on the internet is that the aircraft was being blown around a lot in severe to extreme turbulence, but I don’t see how thereby one would get discrepant readings: rather, all probes would vary wildly, but coordinated, as individual gusts hit all three at more or less the same time. So I really don’t see that as a plausible reason for the P-S system issues.

The IR units are self-contained: they are calibrated sometime way back when and that’s it for the remainder of the flight. So when they start complaining, it is either a system fault or you are already out of control and moving them around more than they judge appropriate.

Severe icing alone overwhelming the sensor systems, though, does not by itself lead to an accident. The AC could be controlled with pitch and power, and the Aircraft Operating Manual explains exactly what pitch and what power setting in some detail, if one has an “ADR disagree” warning.

Severe turbulence, though, could cause a control problem if there are shears of more than 50-60 kts differential, because that is approximately the width of the speed band for that flight at its cleared flight level - this has been verified, using a conservative estimate of the aircraft’s weight at the time, by experienced A330 pilots (by “speed band”, I mean the difference between “maximum Mach operating” speed and stall speed). However, turbulence of that sort, while supposedly possible, is very, very unusual.

How do you get that severe icing overwhelming the PS systems? Temperature at that altitude is well below the freezing point for water, so clouds are generally formed from ice crystals. The properties of these are well known and the air data systems and their certification is aimed to cope with them, unless there is an entirely new phenomenon manifesting itself here. Ice crystals don’t show up on weather radar, so even with careful use of weather radar one might not fathom the presence of a storm whose water content is crystalline ice, no matter how violent that storm is.

The behavior of supercooled water droplets doesn’t seem to be as well understood. Water can become supercooled, even as low as -40°C (which would be a typical temperature for the flight level at which AF 447 was flying), especially in strong convective atmospheric currents. Water requires a certain amount of energy to crystallise, and if the air is cooling fast, adiabatically, that energy just might not be there. And if there is enough water, at -40°C, colliding with your sensors and freezing on impact, it may overwhelm the sensor heating and cause air data problems. However, supercooled drops are water and would show up on weather radar. One would expect a crew to avoid such an area being “painted” on their radar, especially in the Intertropical Convergence Zone (ITCZ) in which such storms are frequent, indeed expected. It is common for pilots to deviate many tens of miles from the planned track to avoid such storms, for avoiding the storm is the main priority, and use of the oceanic tracks is designed to accomodate such deviations.

So the severe-icing root-cause hypothesis is not puzzle-free.

What about some sudden, catastrophic structural-failure event such as the sudden in-flight break-up of TWA 800 in 1996? Any such hypothesis must accomodate the fact that parts of the electronics were muttering to themselves in a fairly orderly fashion, and transmitting those mutterings over a SATCOM link, for some four minutes. I don’t see how. (It is obvious that structural-failure occurred – the aircraft’s vertical stabiliser has been found separated – but, one would conclude, later in the accident sequence.)

That is enough tea-leaf reading for one note. We might hope that the BEA will explain the exact meaning of the ACARS messages, and its conclusions about their true ordering, in the interim report which, by ICAO rules, must appear within 30 days of the accident (so, by 1 July 2009).

If anyone has more detail on the exact JASC codes used by the airline and (very important!) can demonstrate to me that that information is reliable, I would be very glad to hear from you.



You'll find more over at The Abnormal Distribution including a demonstration of how a simple transcription error in a post on PPRuNe ended up propagating around the world.
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Old 14th Jun 2009, 10:49
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For info, the spoiler from the wreckage is the left hand inboard spoiler.
I think you're right. The following photos show it perhaps a bit better. The first is from an identical model also in Air France service, F-GZCG (and you can see the same 3 - 1 - 3 distribution of rivets in the centre, which I presume will be the same on the crash a/c):

Photos: Airbus A330-203 Aircraft Pictures |

This one, in TAM service, shows the narrowing & curvature at the rear corner:

Photos: Airbus A330-223 Aircraft Pictures |

Contrast it with this from F-GZCC on the right side:

Photos: Airbus A330-203 Aircraft Pictures |

And for an overhead shot:

Photos: Airbus A330-203 Aircraft Pictures |
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Old 14th Jun 2009, 10:59
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Useful stuff, PPT. I am very puzzled by the LRGyro in the ISIS throwing a wobbly 'at the same time'. I can only surmise either exceedance of attitude limits (if any), power suply issues or a software glitch. Sadly my old git's instinct points ME to number 3. Surely the odds of a cotemporal failure there are remote? PJ2? Is there any (unlikely?) cross-tell between ADIRUs and ISIS?

EDIT: I do query PBL's diagnosis of the ISIS fault, however "At a similar time, the DG in the stand-by flight instrument system complains." - what is a 'DG'?
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Old 14th Jun 2009, 11:15
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The FA-Seats come imho from the front. There the fuselage sleeks down already to the cockpit. The anunciator Panel got separated, if you draw lines from the brown spots (holes from screws broken out) you get the panel-size. The headrests are gone as well as the plastic cover. However the metal fixings of the plastic panel are visible.
Note also the opening to the lower right of the panel besides the seats. In the picture below there is an access panel visible.

I only found a picture (hope the link works) of those seats from a Ethinad-Airways A330, but you can see the point.

Photos: Airbus A330-243 Aircraft Pictures |

If my asumpttion is correct, i dont know. It might be speculative.

My thanks by the way to the mods, i´m longtime out of flying, however such a tragedy keeps coming back t my thoughts again and again.
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Old 14th Jun 2009, 11:19
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Me Myself,

Your post at 5.46 today...Spot on IMO.

1. Go round the weather if you can ( you normally can)

2. There`s normally no excuse for going into v bad weather. As I`ve said before in 22 years of LH flying I can count on one hand how many times I`ve been in a storm- Most of them at low level too...Where theres more margin..Ie on decent or climb out of somewhere.

3. Go round the weather....AF 447 is probably going to be a sobering lesson to all of us, I think/hope.
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Old 14th Jun 2009, 11:48
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A330 FCOM Bulletin No. 810/1 (Jun 2004)
< but still present in recent FCOM revision >


Two recent fatal accidents on non-Airbus aircraft and several reported incidents attributed to unreliable speed and/or altitude indications have prompted the need to improve flight crew awarness to identify and tackle the failures described in this bulletin.
Most failure modes of the airspeed/altitude system are detected by the ADIRS and lead to the loss of the corresponding cockpit indications and the triggering of the associated ECAM drills.
However, there may be some cases where the airspeed or altitude output is erroneous without being recognized as such by the ADIRS. in this cases, the cockpit indications appear normal, but are false, and pilots must rely on their basic flying skills to identify the faulty source and take the required corrective actions. When only one source provides erroneous data, the straightforward crosscheck of the parameters provided by the 3 ADRs allows the faulty system to be identified. This identification becomes more difficult in extreme situations when two, or even all three, sources provide erroneous information.

This FCOM Bulletin provides the following information:

1. Recall of pitot/static system layout;
2. Situations which may lead to erroneous, airspeed/altitude indications;
3. Consequences of various failure cases;
4. Recall of recommended operational procedures.

- The CAPT side pitot and static probes supply the ADIRU 1 which is normally used for display on the CAPT PFD.
- The F/O side pitot and static probes supply the ADIRU 2 which is normally used for display on the F/O PFD.
- The STBY pitot and static probes supply the ADIRU 3 which can be used for display on either PFD in case of failure. They also directly supply the standby instruments.
<read: "ISIS">

The most proberly reason for erroneous airspeed and altitude information is obstructed pitot tubes or static sources. Depending on the level of obstruction, the symptoms visible to the flight crew will be different. However, in all cases, the data provided by the obstructed probe will be false. Since it is highly unlikely that the aircraft probes be obstructed at the same time, bt the same amount, and in the same way, the first indication of arroneous airspeed-altitude data available to flight crews, will most proberly be a discepancy between various sources.

All aircraft systems using anemometric data have fault accomodation logics. The fault accomodation logics are not the same for the various systems; but rely on voting priciples whereby when one source diverges from the average value, it is automatically rejected and the system continues to operate normally with the remaining two sources. This principle applies to flight controls and flight guidance systems.

Each PRIM receives the speed information from all ADIRUs.
It compares the 3 values
Pressure altitude information is not used by the PRIM.
Each FE (Flight Envelope Computer) <FMGEC> receives the speed and pressure information from all ADIRUs.
For each of these two parameters, it compares the 3 values.

The PRIM and the FE <FMGEC> eliminate it without any cockpit effect (no caution, normal operation is continued), except that one display is wrong and CAT III dual can no longer be available on the FMA.


The autopilot and the autothrust are disconnected by the FE<FMGEC> (whichever autopilot is engaged).
If the disagree lasts for more than 10 seconds, the PRIM triggers the ADR DISAGREE ECAM caution.
It reverts to Alternate 2 law (without high and low speed protection)
On both PFD, "SPD LIM" flag is shown, no Vls and no Vsw is displayed.

This situation is latched, untill a PRIM reset is performed on the ground without any hydraulic pressure.
However, if the anomaly was only transient, the autopilot and the autothrust can be re-engaged when the disagree has disapeared.


The System will reject the 'good' ADR and will continue to operate using the two 'bad' ADRs. This situation can be met when. for example, two or three pitot tubes are obstructed at the same time, by the same amount, and in the same way. (Flight through cloud of volcanic ash, takeoff with two pitots obstructed by foreign matter (mud, insects)).
Human beings (the pilot) tend to use the same type of 'fault accommodation' principles to detect an erroneous IAS/altitude indication. Flight crews will tend to reject the outlier information, if the other two outputs are consistent. This choice is, in the majority of cases, correct; but, all flight crews should be aware of very extreme and unlikely situations where two (or even three) speed/altitude indications can be consistent and wrong.


The following chart provides a non-exhaustive list of the various consequences of various cases of partially or totally obstructed pitot tubes and static ports on airspeed and altitude indications. It should be noted that the cases descibed below cover extreme situations (e.g. totally obstructed or unobstructed drain holes) and that there could be multiple intermediate configurations with similar, but not identical, consequences.

Water accumulated due to heavy rain, Drain holes unobstructed.
-Transient speed drop until water drains
-IAS fluctuations.
-IAS step drop and gradual return to normal.

Water accumulated due to heavy rain, Drain holes obstructed.
Permanent speed drop.

Ice accretion due to pitot heat failure or transient blocked due to severe icing, unobstructed drain holes.
-Total pressure leaks towards static pressure.
-IAS drop until obstruction cleared/fluctuation if transient erratic ATHR if transient.

Ice accretion due to pitot heat failure or transient blocked due to severe icing, obstructed drain holes.
-Total pressure blocked
-Constant IAS in level flight until obstruction cleared.
in climb IAS increases.
in descent IAS decreases.
-Abnormal AP/FD/ATHR behaviour:
a) AP/FD pitch up in OPN CLB to hold target IAS.
b) AP/FD/ pitch down in OPN DES to hold target IAS.

Total obstruction of static ports on ground.
- Static pressure blocked at airfield level
- normal indications during T/O Roll
- After lift off altitude remains constant
- IAS decreases after lift off
- IAS decreases when aircraft climbs
- IAS increases when aircraft descends.

Based on the information given in the preceding chart, it is clear that no single rule can be given to conclusively identify all possible cases of erroneous airspeed/altitude indications. However, any case of erroneous speed/altitude indications will always be associated to one (or more) of the following cues:
a) fluctuations of airspeed indications;
b) Abnormal correlation of the basic flight parameters (IAS, pitch, attitude, thrust, climb rate):
- IAS increasing with large nose-up pitch attitude;
- IAS decreasing with large nose down pitch attitude;
- IAS decreasing with node down pitch attitude and aircraft descending;
c) Abnormal AP/FD/ATHR behaviour;
d) Undue staal warning or overspeed warnings;
e) reduction of aerodynamic noise with increasing IAS;
f) Increase of aerodynamic noise with decreasing IAS.


The procedures descriped below are intended to provide flight crews with general guidelines to be applied in case of suspected erroneous airspeed/altitude indications.


if it is obvious that the outlier is wrong, select the corresponding ADR OFF and reconfigure the PFD indications accordingly, by appling the ECAM drill which will be automatically displayed.
Flight crews should, however, be aware that in extreme circumstances, it may happen that two, or even all three ADRs may provide identical and erroneous data. Therefore, the suspect ADR should only be switched OFF, if it is positively confirmed that the two other ADRs are correct. if in doubt:


The initial pitch attitude and thrust values given in the QRH should be considered as 'Memory Items', since they allow 'safe flight conditions' to be rapidly established in all flight phases (takeoff, climb, cruise) and aircraft configurations (weight and slat/flaps). Once the target pitch attitude and thrust values has been stabilized. the expanded data of the QRH(Flight with unreliable speed indication) should be followed to determine the precise pitch attitude and power setting required, as a function of the aircraft's weight, configuration and desired speed.
After applying the QRH procedure, and when aircraft is stable, the flight crew should try to identify the faulty ADR(one or more). Once the dicrepant ADR has (or have) been positively identified, it (they) should be switced OFF. This will trigger the corresponding ECAM warnings and the associated drills which should be followed to adress all the consequences on the various aircraft systems.

<End of Bulletin >

A330 Tech
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Old 14th Jun 2009, 11:59
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spoiler panel condition

Unlike the VS, the spoiler panel is coated with oil/fuel/hydro fluid residue. Taken with the central disruption caused when the actuator was torn away, it's pretty safe to conclude that this panel detached when the wing was destroyed on impact with the water.

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Old 14th Jun 2009, 12:04
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There is no way I`m blaming your colleagues in AF.

I am saying we ALL (All pilots and the industry in general- me included) have a lot to learn from this tragic accident....Speaking the bleeding obvious
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Old 14th Jun 2009, 12:19
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I am surprised this is a issue as the rudder is obviously not used in the cruise.
The rudder is in constant use in the cruise (at least while the auto-flight system is engaged and operating correctly).

1. How far from the wreckage field was it?
Already answered.

2. Did it detach in the same place and in the same manner as the American Airlines fin failure. Has anyone got pictures of both fins to compare?
Unknown at this time although there is yet to be any evidence given by the investigators to say when or how the fin detached. The photos of both have been posted numerous times and prove absolutely nothing.

3. Can it be determined whether the fin detached before impact with the water?
Yes it can. By qualified investigators, their engineering teams and by advanced computer simulations. Not by armchair experts and conspiracy theorists.


Is there any amplification of early report of body(s) with ox mask (pax or full face?), and recent report "masks found"?
Not that I have seen, read and heard so far. I think the only official description is that the bodies were unclothed. Masks have been found and photographs have been released of these but no indication or statements so far to say they were found on the bodies.

Last edited by Mercenary Pilot; 14th Jun 2009 at 13:10. Reason: Added Photo
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Old 14th Jun 2009, 12:30
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Inertial Units

'The IR units are self-contained: they are calibrated sometime way back when and that’s it for the remainder of the flight. So when they start complaining, it is either a system fault or you are already out of control and moving them around more than they judge appropriate.'

These are strapdown systems which integrate up rates and accelerations. If the dynamics exceed certain limits the attitude reference will diverge as the integration errors mount up and effectively cause cross channel coupling as the sensor inputs are incorrectly resolved. However do you know that air data isn't used in some damping mode via clever kalman filtering or integrity/sanity cross-checking ?

Any significant to apparent lack of faulting from other systems eg engines ?
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Old 14th Jun 2009, 12:34
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at 0212, a 3422 event in the standby flight instruments (ISIS) (34 is navigation, 3422 is directional gyro and indicators)
Then the laser ring gyro in the ISIS complains,

IF there was no attitude reference,it was mission impossible.Why no mechanical gyro?You must leave the pilot something(SAI/compass)when the primary technology fails.Mechanical gyro has moving parts and can topple but is ROBUST.KISS.

I'm afraid you wont be very popular here.You have my sympathies.
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Old 14th Jun 2009, 12:40
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FDR/CVR recovery.

Given the demonstrated ability of VS/rudder assemblies to float would it be technically possible to locate the FDR and CVR inside the VS?
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Old 14th Jun 2009, 12:54
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Quote by 747guru ....... who asks about "burst" transmissions

I know little about IT, but as you say, there MUST be a way that modern aircraft can transmit "burst" transmissions on a regular basis (say every 20min) to home base including ALL the info that would normally be stored on the FDR/CVR?

OK a lot can happen in the 20min between transmissions, but surely a pattern may emerge leading up to a serious incident?

Dating from the early 1960s Lockheed Skunk Works used 'BirdWatcher' on the U-2 and later on the A-12 and derivatives to keep an eye on these aircraft in flight . It effectively tracked disasters - aerodynamic, mechanical or combat related. Aircraft parameters such as altitude, overspeed, canopy off, electrical faults, high tgt, flameout and many more were compressed and then event transmitted by a short burst of HF to homeplate. When things were going well, the pilot would use the cockpit BW transmit key to signal/authenticate a task done - complete with the flight parameters relevant to that time period. The many Area 51 websites give some insight into this remarkable precursor to ACARS and the satellite monitoring technology of today.

Like so many Kelly Johnson schemes, it worked well in real life. Thus BirdWatcher was able to provide plausible likely scenarios and reasons for the many disasters encountered in the early 1960s.

See A-12, YF-12, SR-71 Blackbird crashes
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Old 14th Jun 2009, 13:10
  #1458 (permalink)  
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ACARs Rosetta Stone Finally Deciphered

Yeah BOAC,

Good point. I recall other bus guys earlier in the thread complaining about repeated failures of that unit (ISIS.) But in this case, I think Professor Ladkin's use of the term "DG" is wrong. Also Ladkin's use of only four digit codes for the ACAR's faults does not seem very accurate to me. Faults are six digit. Warnings only four. For example the 3411 he references is not as descriptive as the actual 341115 which denotes more than just a problem in the Pilot static system; it denotes more specifically that either the heater or the computer that monitors the Airspeed Probe pressure data has faulted.

Also, there is something important that you all need to know. After considerable digging for 24 hrs, I have a fairly good opinion that the France2 TV shots are a SITA reformat of the AOW2 satellite data. That means, as a few sharp minds on pprune have mentioned, that it is just a "leg report" and as such, is TRUNCATED for brevity. My college degree is in computer studies. Still, for some reason, it did not occur to me that the ellipses (...) mean there's more information available than is being displayed. Recall, if you will, that one poster was objecting, a thousand posts or so ago, that the message was incomplete and it did not include pitot 1,2,3 failure language. I feel certain now, because of the ACARs standard conventions which SITA follows, which sends a second set of transmissions to check for errors, that the 0210z to 0214z list is complete with all the message events that were sent for that time period. We can't see specific language to Pitot probe failures, because SITA ommitted them (...) in order to get the warning or fault listed on one line. Greenspinner and others, IIRC, were complaining that we needed the full Aircraft Maintenace Report for AF447, which for whatever reason, was not leaked to FranceTV2, or they decided not to air the final flight maintenance report, or it never made it before breakup.

To Recap:

The screen shots are authentic and complete as far as France2 knows.
They are missing key mention of Pitot triple failure because (...) the program SITA truncates the Sat message for one-line brevity on the leg report only.
The 341115 code is confirmed by our techs here at pprune to be the pitot.

Captain "Ironside" Crunch - out

The above, as all my post are, are just my opinions only.


Last edited by Captain-Crunch; 14th Jun 2009 at 13:51. Reason: RTFQ: ISIS, changed from full report to final flight mtc rpt
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Old 14th Jun 2009, 13:35
  #1459 (permalink)  
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quite a few holes in that piece from an apparent professor. However lets assume its genuine.

For the 6,000,000,000,000 million billion time, there could be a weeks delay in sending the acars messages they will still show aircraft system time taken from the aircraft reference clock as indicated at the time of the event. I don't know how to make that any clearer.

ISIS is not just a laser ring gyro. It also has pitot/static inputs from the systems being logged as faultly. Maybe thats why it logged a fault message

The one message that remains puzzling is the ir fault. Perhaps yes because the aircraft had already exceeded some limits but that is pure speculation.
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Old 14th Jun 2009, 14:17
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Originally Posted by A33Zab

The System will reject the 'good' ADR and will continue to operate using the two 'bad' ADRs. This situation can be met when. for example, two or three pitot tubes are obstructed at the same time, by the same amount, and in the same way. (Flight through cloud of volcanic ash, takeoff with two pitots obstructed by foreign matter (mud, insects)).
Human beings (the pilot) tend to use the same type of 'fault accommodation' principles to detect an erroneous IAS/altitude indication. Flight crews will tend to reject the outlier information, if the other two outputs are consistent. This choice is, in the majority of cases, correct; but, all flight crews should be aware of very extreme and unlikely situations where two (or even three) speed/altitude indications can be consistent and wrong.
A lightening strike at the right side of the cockpit could damage both FO and standby pitots as they are mounted close to each other.

Then we could easily have a situation as described above where the system is rejecting the 'good' ADR.
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