Qantas A330 Emergency Landing in Learmonth
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DTH, Totally agree with you. But as an Airbus driver i think what Airbus has pumped out sofar is not enough., I would like to see a full printout of the event, as they do normally, so the next time i leap into the air, i'm not guessing what went on in that cockpit.. I'm not knocking the crew and their actions btw.
derek zoolander: I'm by no means an expert, but I do know a little bit about Air Data Computers and IRUs. I work on aircraft that still have these systems seperated, rather than newer models that have ADIRUs.
Having said that, the accellerometers are part of the "IRU" part of the equation. They provide accel data for each of the three planes of movement, which the IRU then integrates a couple of times to get distance. Combine these three measurements and given a reference point and you can calculate present position.
The reports about this Qantas incident point to erroneous Angle of Attack values provided by ADIRU, which would not be data derived from an accellerometer. Accellerometers don't care and couldn't guess which direction the nose is pointed in relative to airflow, so I think this guy is probably putting 2 + 2 together and getting 5.
Anyway, hope this has been helpful. Nobody get your knickers in a knot if I've got some terminology wrong!
Having said that, the accellerometers are part of the "IRU" part of the equation. They provide accel data for each of the three planes of movement, which the IRU then integrates a couple of times to get distance. Combine these three measurements and given a reference point and you can calculate present position.
The reports about this Qantas incident point to erroneous Angle of Attack values provided by ADIRU, which would not be data derived from an accellerometer. Accellerometers don't care and couldn't guess which direction the nose is pointed in relative to airflow, so I think this guy is probably putting 2 + 2 together and getting 5.
Anyway, hope this has been helpful. Nobody get your knickers in a knot if I've got some terminology wrong!
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Triple Redundancy?
I ask a simple question. What happened to the triple redundancy we hear so much about?
IF there are three ADIRU boxes and one begins to put out different data to the other two, why isnt it automatically isolated and the output from the other two utilised from then on?
I'd appreciate a comment from an A330/A340 driver.
IF there are three ADIRU boxes and one begins to put out different data to the other two, why isnt it automatically isolated and the output from the other two utilised from then on?
I'd appreciate a comment from an A330/A340 driver.
HotPete
It should. That is why there is such interest about this incident. Airbus are just about if not already about to issue a new “OEB” so that crew can be better prepared to deal with this kind of failure until the root cause of this problem is fixed.
It should. That is why there is such interest about this incident. Airbus are just about if not already about to issue a new “OEB” so that crew can be better prepared to deal with this kind of failure until the root cause of this problem is fixed.
The similarity between the MAS 777 and this incident is that erroneous data was able to find its way to the flight control computers. The way this occured is different. The ADIRU on the 777 is a Fault Tolerant ADIRU. Boeing decided that they didn't want pilots mucking around with switching from one ADIRU to another so Honeywell put all the bits in the one box. Their were multiple units ( i.e. 6 accelerometers), which would automatically switch in case of a single failure. The idea being that the single ADIRU unit would never have to be removed from the aircraft during its entire service life, (hence the fault tolerant bit). What happened in reality was that Honeywell were getting quite a few of these units sent back to them because of transient failures. They installed a different version of the operating software which allowed for transient failures of an accelerometer for example, to be monitored over 1000 flight hours and if it behaved itself then it would be allowed back into the game.
What happened with the MAS 777 was that a second accelerometer failed, so the OPS bought an accelerometer back into the game that had failed months previously. By failed I mean that they were producing high acceleration values. These high values were now fed to the flight control computer and the autopilot responded accordingly.
From the information released so far about QF72 it seems that the main issue is how the erroneous data was able to get to the flight control computer. My personal opinion is that somewhere some software was modified and this allowed dud data to go to places dud data should not go.
Crikey.com never lets the facts get in the way of a good beat up.
What happened with the MAS 777 was that a second accelerometer failed, so the OPS bought an accelerometer back into the game that had failed months previously. By failed I mean that they were producing high acceleration values. These high values were now fed to the flight control computer and the autopilot responded accordingly.
From the information released so far about QF72 it seems that the main issue is how the erroneous data was able to get to the flight control computer. My personal opinion is that somewhere some software was modified and this allowed dud data to go to places dud data should not go.
Crikey.com never lets the facts get in the way of a good beat up.
What cannot understand is that one ARIDU out of three can give incorrect data to the Flight Control Primary Computers and these computers act on that info.
What did the software do to the info from the other two (correct) ARIDUs.
Is the software written so that if one of the ARIDUs gives an output that indicates the aircraft is moving into an abnormal flight situation, the three Flight Control Primary Computers will give preference to that info rather than the info from the other two which indicates that the aircraft is operating normally and act accordingly?
What did the software do to the info from the other two (correct) ARIDUs.
Is the software written so that if one of the ARIDUs gives an output that indicates the aircraft is moving into an abnormal flight situation, the three Flight Control Primary Computers will give preference to that info rather than the info from the other two which indicates that the aircraft is operating normally and act accordingly?
Bottums Up
One report I've read somewhere, perhaps even on this thread, suggest that the ADIRU was expected to fail power (electrical) dead, not power positive, whereby it send out erroneous signals.
From today's Sydney Morning Herald website titled "Passengers Seek Compo"
"QF72 from Singapore to Perth fell 1050 feet in less than a minute on October 7, slamming passengers into the cabin roof and walls."
Watch your VSI's guys, I feel another 40 million claims coming on. Better still, just try to avoid landing altogether.
"QF72 from Singapore to Perth fell 1050 feet in less than a minute on October 7, slamming passengers into the cabin roof and walls."
Watch your VSI's guys, I feel another 40 million claims coming on. Better still, just try to avoid landing altogether.
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Triple Redundancy?
I ask a simple question. What happened to the triple redundancy we hear so much about?
IF there are three ADIRU boxes and one begins to put out different data to the other two, why isnt it automatically isolated and the output from the other two utilised from then on?
I ask a simple question. What happened to the triple redundancy we hear so much about?
IF there are three ADIRU boxes and one begins to put out different data to the other two, why isnt it automatically isolated and the output from the other two utilised from then on?
I am assuming that QPA would have been single engaged, thus operating on the command of 1 ADIRU when this occured. Can anyone correct me if I am wrong? I cannot understand why A/P commands would be voted (as people are saying) during single channel engage in cruise, but then again, I am not a bus person.
Mid-morning update from online Age newspaper:
This theory from memory was suggested by several posters.
MEDIA RELEASE : 14 November 2008 - ATSB Preliminary Factual Report, In-flight upset, Qantas Airbus A330, 154km west of Learmonth, WA, 7 October 2008
Naval base transmissions may have led to Qantas jet plunge
Kerryn Macaulay, of the Air Transport Safety Bureau, said yesterday it was considered unlikely that a low frequency transmission from the Harold E. Holt transmitter near Exmouth could have caused the problem but that possibility was still being investigated.
She said it was also possible that an electronic device being used by a passenger might have interfered with the aircraft's computer system.
Ms Macaulay said examination of information from the aircraft's flight data recorder indicated that at the time the aircraft's autopilot was disconnected.
- Brendan Nicholson
- November 14, 2008 - 10:46AM
Kerryn Macaulay, of the Air Transport Safety Bureau, said yesterday it was considered unlikely that a low frequency transmission from the Harold E. Holt transmitter near Exmouth could have caused the problem but that possibility was still being investigated.
She said it was also possible that an electronic device being used by a passenger might have interfered with the aircraft's computer system.
Ms Macaulay said examination of information from the aircraft's flight data recorder indicated that at the time the aircraft's autopilot was disconnected.
MEDIA RELEASE : 14 November 2008 - ATSB Preliminary Factual Report, In-flight upset, Qantas Airbus A330, 154km west of Learmonth, WA, 7 October 2008
Last edited by Teal; 14th Nov 2008 at 00:03.
Misleading bloody media again. 
In the text of the media release they state:
Never mind Bendan Nicholson just run that as the main thrust of the article even though it is an unlikely cause. 
A good jouno would still be able to engage the public with a relevant article.
Is Brendan one of the 55?
In the text of the media release they state:
This [RF interference] is unlikely, especially if the problem is clearly identified during the ADIRU and system testing.
A good jouno would still be able to engage the public with a relevant article.
Is Brendan one of the 55?
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Prelim ATSB report
Interesting read:
http://www.atsb.gov.au/publications/...070_prelim.pdf
The FDR plots near the end (page 39-onwards, although labelled 29) would give you pause.
http://www.atsb.gov.au/publications/...070_prelim.pdf
The FDR plots near the end (page 39-onwards, although labelled 29) would give you pause.
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Just as a point of interest I wonder if the flt crew where whilst attempting to find out what caused the A/P to trip off in the first place (there was 2 mins elapsed time whilst the A/C was 'autopliotless') inadvertently did something to cause the upset without even knowing it? The crew may very well have been doing what most of us would be doing, apart from simply resetting the A/P they might have been trying other ways around the problem before calling base for advice. Such 'fiddling' could have been done at random & this eventually caused the excursion from otherwise level flight. Just a thought & no malice intended towards the flight crew.
CW
CW
OOHHHH this is a pearler……
I can just see the headline in the Terrorgraph now.
“Qantas Jet in death plunge”
followed by the subtext………
"narrowly misses outback primary school" (closed in 1984)
“believed to be linked to the Navy transmission of a VLF acknowledgement message to the submarines first diving mate that her breast enlargement surgery had been approved by the navy to enhance her self esteem and hence mission readiness, and to give the yodas in the back something to chuckle about during annual underwater escape training……………”
FFS
Going on to prove that qantas management might just be the biggest tits in this country! Only just
I can just see the headline in the Terrorgraph now.
“Qantas Jet in death plunge”
followed by the subtext………
"narrowly misses outback primary school" (closed in 1984)
“believed to be linked to the Navy transmission of a VLF acknowledgement message to the submarines first diving mate that her breast enlargement surgery had been approved by the navy to enhance her self esteem and hence mission readiness, and to give the yodas in the back something to chuckle about during annual underwater escape training……………”
FFS
Going on to prove that qantas management might just be the biggest tits in this country! Only just
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Excuse me people if I'm repeating a question put by others, but could an engineering master please answer this. If there are 3 ADIRU's and one, as seems to be the case is giving erroneous data, why isn't this compared to the other two before it's fed into the FMS? Wouldn't that be the redundancy? Why is the data fed directly before being compared?
Sorry if I'm asking a dumb question and if this is what actually occurred are there any MD's or AD's issued by the bus boys?
Sorry if I'm asking a dumb question and if this is what actually occurred are there any MD's or AD's issued by the bus boys?
Last edited by Whiskey Oscar Golf; 14th Nov 2008 at 08:49. Reason: spilling
Capt Wally, I'm disappointed at your last post. I'm surprised you'd think a captain of a thing the size of an A330, who was hand-flying at the time, and his SO, would have been "fiddling around" trying to sort out the situation. Look at the timing - after getting the thing back under control at FL370, not more than a couple of minutes elapsed before the **** hit the fan and the bunting started.