I have noticed that two pilots who regularly post sane comment about this issue have done a lot of work to try and figure out what may have happened. One poster (Mandala499) who is probably the most sane guy there, has done a good job of trying to figure out the timeline of the ACARS messages and re-order them according to their respective time stamps. I didn't get involved in the other AF447 topic because despite the heavy moderation, it appeared to be going in circles most of the time... and missed the one here. That list still needs revision... it's been revised hundreds of times already. I do need help on those just to see what happened based on the ACARS (to the limit of what the ACARS can give). How I think (personal theory) the plane went up to 0210 is on the works too but I keep coming back to the ACARS... although I need to match it up with the last position and where it was in terms of the weather (which sadly, indicates they made it (or almost) out of the weather, only to be hit by something such as icing). This doesn't rule out the occurence of intermitten errors/failures which would not have been picked out by the CMC... but that would be guessing too much. So pardon the inaccuracy if you find one, and help improve it. I still need to know the details of 2CE2, and 22FN-10FC... (the part coding convention does give clues, but not much) I find it interesting that Pitot 1 PHC came up, but ADR2 data downstream of the PHC2, failed. As to difference between F/CTL ADR DISAGREE and NAV ADR DISAGREE??? No answer for the moment... it's equally baffling. However, it seems that the FCOMs I read have NAV ADR DISAGREE but not F/CTL DISAGREE. It might have something to do on where/how the disgreement happened... I was hoping that you guys over here can help. |
My guess is that F/CTL ADR DISAGREE is showing when the FCCs have problems with ADR data, while NAV ADR DISAGREE comes on when the FMGC has problems with it.
You have to understand, that those modern planes take their data from all kind of sources and route them to all different aircraft subsystems. FCC needs the ADR data for computation of stearing commands while the FMGC needs it to compute navigational data. Makes sense? Anyway, as mentioned elsewhere, I do not think that we will get important information about the cause of the crash from the well known ACARS signals. hth, Dani |
To PK-KAR
Nice to 'meet' you PK :)
I will try to elaborate some constructive criticism. I am aware that it might bump into some serious hard work, please take it as I intend it to be, positive thinking to improve general knowledge. Starting from your work, which I take is based upon the famous maintenance messages, two things strike me : is the 34-11-15 fault to be taken as all 3 probes failed together, or as n°1 heating failed ? Finally, how many probes are deemed failed as we can deduce from this message ? The devil hides in the details : in the second message, 0210Z 27-93-34-0, I would like your thoughts on the tiny detail here : ADIRU1 BUS ADR1-2 TO FCPC2 Is the translation "ADR 1 & 2 no signal to FCPC2" correct ? Could it be instead that this BUS ADR1-2 TO FCPC2 refers to the part that connects ADR1 to n°2 parts of the system, here FCPC2 ? Wouldn't a dual ADR failure be named ADR1+2 instead ? This hypothesis from the fact that ADRs are connected crossways to various parts of the system, and not only n°1 parts. And the fact that multiple failures are usually labelled with a + sign. Best regards. |
To Dani and PK-KAR,
please humor my insistence on this point : we need to seriously evaluate the difference between NAV ADR DISAGREE and F/CTL ADR DISAGREE. From various documents I have read (and believe me, I have read quite a lot in a month, and I need to stop else I won't pass my medical because of eyesight), all instances of speed indication failures in the known incidents I could put my hands on were of the following nature : a quick determination of a F/CTL ADR DISAGREE. This failure is well documented, have a look at eurocockpit. On the AF447, we have a slow-in-coming NAV ADR DISAGREE. It might be minor, but I doubt it. AB shows pretty consistent wording throughout their 'namespace'. Since we are oriented towards a similarity between previous incidents and this dreadful crash, we might miss the exact difference which spelled death for so many people. I think we should try to find these differences, and surely some of them are inside the aircraft computations. This NAV / FCTL discrepancy definitely looks like one. Of course, it 'very likely' means that the system which slaps the ADRs out is different in the instances. However, it also means that the overall reaction of various systems throughout the aircraft will be different on the AF447. How different ? |
ir2
I still need to know the details of 2CE2, and 22FN-10FC... (the part coding convention does give clues, but not much) I find it interesting that Pitot 1 PHC came up, but ADR2 data downstream of the PHC2, failed. I think Inertial Data is independent from air data - and that the opposite is not true - so an IR fault would only be detected by comparison with inertial data... Am I Wrong ? P.S.: I know AOA differs from pitch attitude - it relates to the relatively motion of the airflow to the wing - but is there any inertial component in the AOA calculation ? This question is related to the qantas incident... |
IR and ADR linkage?????
FCC needs the ADR data for computation of stearing commands while the FMGC needs it to compute navigational data. My guess is that F/CTL ADR DISAGREE is showing when the FCCs have problems with ADR data, while NAV ADR DISAGREE comes on when the FMGC has problems with it. NAV ADR DISAGREE This caution is triggered by the PRIMs, when they only use 2 ADRs, and these 2 ADRs disagree. This may occur when: - One ADR has already been selected OFF by the pilot, or - One ADR has been eliminated by the PRIM, without any caution, because it deviated from the others. The procedures are identical (both versions are roughly from the same period).. AIR SPD... XCHECK - IF NO SPD DISAGREE AOA Discrepancy - IF SPD DISAGREE ADR CHECK PROC...APPLY F/CTL ALTN LAW (PROT LOST) Note: Following an ADR disagree detected by the PRIMs, the ALTN LAW is latched. Resetting the PRIMs using the pushbutton will not allow recovery of normal law. - MAX SPEED... 330/.82 STATUS - MAX SPEED... 330/.82 CAT 3 SINGLE ONLY RISK OF UNDUE STALL WARNING RUD WITH CARE ABV 160 KT INOP SYS RUD TRV LIM CAT 3 DUAL Both are caused by the PRIMs rejecting 1 ADR and the other 2 disagree with each other... but are they identical? I guess this depends on the airline on where it wants the ADR DISAGREE to appear... coz, I looked at an Airbus document, and it just says "ADR DISAGREE"... *shaking head even more in confusion*. Perhaps it depends on the FWC standard one is using. is the 34-11-15 fault to be taken as all 3 probes failed together, or as n°1 heating failed ? Finally, how many probes are deemed failed as we can deduce from this message ? EFCS1, AFS - PROBE PITOT 1+2/2+3/1+3 (9DA)... AFS senses fluctuation or rejects an ADR, asks EFCS1 to compare the rest, 9DA as problem's suspect. I have a separate list showing 34-11-00, failures of inputs... most of the list is sensor power supply and switching... 34-11-15 is something else... (and different airlines may have different numbers). ADIRU1 BUS ADR1-2 TO FCPC2 yes ADIRU1 BUS ADR1+2 TO FCPC2 makes more sense... The thing is, I don't know the databus layout... ADR 1+2 Failure I think would occur if PRIM1 or none of the PRIMs receive the data... unless PRIM2 was the Master Prim at the time... The "-" instead of the "+" could have just been a typo... The devil hides in the details : INDEED !!!!! we need to seriously evaluate the difference between NAV ADR DISAGREE and F/CTL ADR DISAGREE. How did you get to the relationship between air & phc data and the IR2 fault reported by disagreement with IR1 and IR3 ? I think Inertial Data is independent from air data - and that the opposite is not true - so an IR fault would only be detected by comparison with inertial data... Still got a lot of reading to do (and repeat readings)... PK-KAR |
I know AOA differs from pitch attitude - it relates to the relatively motion of the airflow to the wing - but is there any inertial component in the AOA calculation ? This question is related to the qantas incident... |
ACARS MEssages Partially Decoded
the data available (ACARS
messages) at this stage: -Does not suggest any loss of electrical power -Does not suggest loss of cockpit display units The majority of the messages are linked with unreliable airspeed measurement • Some additional messages are also consistent with unreliable airspeed measurement but require further analysis (hopefully we can all try piece together some info from this) • Others resulted from crew action 02:10 UTC Maintenance message “PROBE-PITOT 1+2/2+3/1+3(9DA)” 2 different sources of trigger: The EFCS detected a speed decrease greater than 30kts in 1s on 2 or 3 airspeed measurements. The AFS detected that each airspeed information compared to the 2 others showed at least transiently a difference greater than 20kts The Above Message, as per its design, triggered the following messages: “FCTL ALTN LAW” “AUTO FLT REAC W/S DET FAULT” “FLAG ON CAPT PFD SPD LIMIT” and “FLAG ON F/O PFD SPD LIMIT” -Indicates that characteristic speeds information (VLS, VMAX….) were no more displayed on PFD -Information displayed on both PFD speed scales * current airspeed, selected airspeed * SPD LIM flag on bottom of airspeed scales “AUTO FLT AP OFF” - Auto disconnect of AP “AUTO FTL ATHR OFF” - Again auto disconnect of ATHR as above “FLAG ON CAPT PFD FD” and “FLAG ON F/O PFD FD” A red flag FD was displayed on both PFD (attitude area) to indicate that FD were disengaged but selected ON At 2:10 UTC message “F/CTL RUD TRV LIM FAULT” Indicates that the FCPC detected a speed variation higher than 50kts in 10s on 2 or 3 airspeed indications Indicates that the rudder travel limit is locked at the position corresponding to the speed immediately before the detected speed variation 02:12 UTC “NAV ADR DISAGREE” -The Flight Control System had already rejected one ADR AND -Out of the 2 remaining ADR’s, the Flight Control System detected a discrepancy on one ADR parameter Other maintenance messages and cockpit effects pointing at ADR system: 02:10 UTC –“FCPC2 (2CE) WRG: ADIRU 1 BUS ADR1-2 TO FCPC2” –“MAINTENANCE STATUS EFCS1” –“MAINTENANCE STATUS EFCS2” 02:11 UTC –“ISIS (22FN-10FC) SPEED OR MACH FUNCTION” –“ADIRU2 (1FP2)” 02:14 UTC –“MAINTENANCE STATUS ADR2" In Relation to other messages triggered: 02:13 UTC –“F/CTL PRIM1 FAULT” and “F/CTL SEC1 FAULT” - SHows PRIM 1 and SEC 1 were either both switched to off or Reset. "FMGEC1 (1CA1)” 02:14 UTC –“ADVISORY CABIN VERTICAL SPEED” - This indicated Cab Vertical Speed was greather than plus or minus 1800ft/min All pieced together from a prelim round up and also trying to shed some light on this |
ADIRU1 BUS ADR1-2 TO FCPC2 yes ADIRU1 BUS ADR1+2 TO FCPC2 makes more sense... The thing is, I don't know the databus layout... ADR 1+2 Failure I think would occur if PRIM1 or none of the PRIMs receive the data... unless PRIM2 was the Master Prim at the time... The "-" instead of the "+" could have just been a typo... This reasonably cannot be a typo, I have it as a scan of a computer-generated document. How did you go about translating the message into plain English ? |
To PK-KAR
The thing that caught me was that the FPV would disappear... FPV would largely be a result of all things IR and the only ADR part is barometric... What you end up with is either a ground-related FPV (inertial) or an air-related FPV. Which theory was used in the A330 ? Well, answers, answers : from QRHs, on the B777 side we have an inertial FPV, which the QRH states is reliable and to be used in airspeed indications loss situation (unreliable airspeed ind.), on all A320/330/340 the QRH states FPV unavailable... Draw your own conclusions. |
Svarin,
You mean this? http://www.eurocockpit.com/images/PFR447.png ??? From Eurocockpit - Archives One last important thing that we must do : in order to let you compare the events experienced by the flight AF447 with those described in the technical note mentioned above, we would like to expose the actual list of the contents of the famous ACARS messages sent by the plane. In order to keep our sources secret, we have transformed the appearance of the original file, but the content has remained exactly the same. How did you go about translating the message into plain English ? As to the FPV... yes, it needs air data on the 330... it is something I don't get as to if they can get the BUSS (works off pure IR), why not just make the FPV all inertial? Surely air pressure gradients aren't "that" steep? *that one was picked out of the air*... PK-KAR |
other aircraft types with pitot issues
icing:
FR Doc E8-20702 cracks: Docket No. FAA-2009-0005; Directorate Identifier 2008-NM-164-AD] "This proposal would require operators to inspect the pitot tubes. If cracks are found in the tubes, they would need to be replaced, per the instructions of CASA Service Bulletin SB-212-34-11, Rev. 1 (dated Feb. 27, 2008). This proposed AD, which resulted from an MCAI originated by the European Aviation Safety Agency, was prompted by the discovery of cracked pitot tubes on Britten-Norman BN-2 aircraft, which use the same Thales Optronics pitot tubes as are found on CASA C-212s. Cracked pitot tubes could result in incorrect readings on the pressure instrumentation (e.g., altimeters, vertical speed indicators and airspeed indicators), potentially leading to navigational errors. FAA estimates that this proposed AD would affect 32 aircraft on the U.S. Registry and cost U.S. operators a total of $2,560, or $80 per airplane. Comments on this proposal, which are due March 25, should be sent to the DOT Docket Web site:" http://dms.dot.gov; overheating: "AIRLINE INDUSTRY INFORMATION July 29, 2002 United Airlines aircraft aborts flight due to faulty airspeed indicator A United Airlines aircraft flying from Los Angeles to Washington DC was forced to abort its flight after was smoke was detected in the cockpit. The aircraft - an Airbus A320, carrying 122 passengers - had been in flight for about 40 minutes when smoke began entering the cockpit. The flight returned to Los Angeles International Airport, where the passengers safely disembarked from the aircraft. According to officials, the smoke occurred after a Pitot tube (which indicates airspeed) mounted on the fuselage overheated. The aircraft was expected to return to service once the faulty part was replaced, reported Reuters." |
A few more pitot incidents may be found in the article below:
Airbus crash: can a triple-redundant system give false readings? (Tony Collins's IT Projects Blog) |
Hi
Cam any of you guys help me out here (susbseuent to my post on this topic being deleted from R&N ( I am not a pilot nor a journalist, just a curious sort of person) The crashed aircraft was invoved in a taxying incident in 2006 during which it suffered wing damge described as "minimal." The other aircraft involved suffered "substantial" tail damage ( see []www.jadec.de/years/all2006.txt) are there any international regs regarding post repair inspections for this specific type of incident or are they company-specific ? Any help would be much appreciated peter |
Celtic Mech, thank you for your very clear explanation
Coming a little late, and about the Nav ADR disagree message, the BEA (French investigation preliminary report) explains it thus: Signification : ce message indique que les EFCS ont rejeté une ADR, puis identifié une incohérence entre les deux ADR restantes sur l’un des paramètres surveillés. That is: this message tells that the EFCS have rejected one ADR, then has identified a discrepancy between the two remaining ADRs concerning one of the parameters. For what it is worth...but as they work closely with Airbus I think we can trust them on that. |
Type of failures
@Svarin
in the second message, 0210Z 27-93-34-0, I would like your thoughts on the tiny detail here : ADIRU1 BUS ADR1-2 TO FCPC2 Is the translation "ADR 1 & 2 no signal to FCPC2" correct ? Could it be instead that this BUS ADR1-2 TO FCPC2 refers to the part that connects ADR1 to n°2 parts of the system, here FCPC2 ? Wouldn't a dual ADR failure be named ADR1+2 instead ? Quote TSM : Faults triggering an ECAM MAINTENANCE STATUS These faults have no consequence on the system operating conditions. They are always GO without any restriction. Quote TSM: Loss of the ADIRU1 ADR Bus 2 Input in the FCPC 1. Possible Causes - FCPC-2 (2CE2) - FCPC-3 (2CE3) - wiring of the DGI 10 Bus from the related FCPC COM side to the first terminal block - wiring of the DGI 10 Bus from the related FCPC MON side to the first terminal block Hope to shed some light :) |
Greetings
SVARIN FPV uses Ground Speed over Rate of Descent, both data are inertial (earth related) |
Rain And Sound At -51c
I have been studying the ice particle icing issue and would like to communicate with the pilot and others regarding the conditions experienced, especially the sound characteristic reported during the apparent rain event at -51C. He reports a "sound of the plane getting pelted like an aluminum garage door". It would be interesting to characterize the sound quality to better identify the conditions. There are also a number of other questions that he or others may have observed that may be meaningful.
I believe I understand the "ice particle icing" issue and would like to wrap it up. If the pilot you quoted wishes anonymity, that is certainly alright. I would simply like to receive his observations. As a point of reference, I am a chemist and a pilot. |
Just diverging slightly, I haven’t spotted any discussion in the 3 threads running on this accident to possible icing/blockage of the static vents (they are all in close proximity to each-other) and the effect thereof.
I find it slightly bewildering why, when the altitude was obviously bleeding off and the wings were level the crew appears not to have initiated a nose down pitch for stall recovery. Or can we possibly conclude that the controls were compromised i.e. jammed horizontal stabaliser, preventing this. |
Backoffice
when the altitude was obviously bleeding off and the wings were level the crew appears not to have initiated a nose down pitch for stall recovery. |
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