Qantas emergency landing
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The ATSB just released their preliminary report on this accident. Here's the link (43 pages - 'pdf'):
http://www.atsb.gov.au/publications/...070_prelim.pdf
Here's the media release that accompanied the report (includes brief synopsis):
MEDIA RELEASE : 14 November 2008 - ATSB Preliminary Factual Report, In-flight upset, Qantas Airbus A330, 154km west of Learmonth, WA, 7 October 2008
http://www.atsb.gov.au/publications/...070_prelim.pdf
Here's the media release that accompanied the report (includes brief synopsis):
MEDIA RELEASE : 14 November 2008 - ATSB Preliminary Factual Report, In-flight upset, Qantas Airbus A330, 154km west of Learmonth, WA, 7 October 2008
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RF interference
Sorry, late to this thread, but many years ago in a B737/200 over N Wales around FL370, inbound to MAN, the A/P pitch channel dropped out for no apparent reason (1 A/P, separate Pitch & Roll channels --High Tech stuff). It was duly re-engaged and a few seconds later dropped out again, again with no warnings. Last try attempted, and stayed in for a few seconds, under close supervision, then once more out she goes, but his time with the Skipper's hands on the stick and a lot of attention we saw/heard there was a momentary stick shake (Stick Shaker activation automatically takes out the A/P Pitch channel).
Continued to MAN uneventfully, and were sitting on the ramp with the Tech Log out, wondering how to write this up so it made some sense, when the Ground Engineer arrives. Seeing our puzzlement he says "Autopilot Pitch Channel?" we both nod. "OK" he says, "Write `FL3X0 over N Wales. Repeated A/P Pitch Channel disconnects with momentary Stick Shaker activation'. "How do you know that?" we ask.
"Third today, the military must be up to something around the LLanbedr ranges!" (Lots of live ranges, radars etc in that area).
Different A/C. Different place and time, but similar results.
Fragman
Continued to MAN uneventfully, and were sitting on the ramp with the Tech Log out, wondering how to write this up so it made some sense, when the Ground Engineer arrives. Seeing our puzzlement he says "Autopilot Pitch Channel?" we both nod. "OK" he says, "Write `FL3X0 over N Wales. Repeated A/P Pitch Channel disconnects with momentary Stick Shaker activation'. "How do you know that?" we ask.
"Third today, the military must be up to something around the LLanbedr ranges!" (Lots of live ranges, radars etc in that area).
Different A/C. Different place and time, but similar results.
Fragman
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Volume thoughtfully queried:
Does anybody know by heart the frequency range tested during L/HIRF certzification tests? (there must be some FAA-AC around specifying the frequencies to be tested), and does anybody know the "low frequency" used to communicate with subs? Are we talking kHz range, or lower?
Maybe nobody thought of such low frequency high energy radio transmissions when designing the electromagnetic shielding of the computers ?
Does anybody know by heart the frequency range tested during L/HIRF certzification tests? (there must be some FAA-AC around specifying the frequencies to be tested), and does anybody know the "low frequency" used to communicate with subs? Are we talking kHz range, or lower?
Maybe nobody thought of such low frequency high energy radio transmissions when designing the electromagnetic shielding of the computers ?
This is not a proper place for discussion or detail about exotic advances in electromagnetrickery, mumble, mumble, but your suggestion, Volume, that industry standard testing specs and methods re EMI are out of date and insufficient may be valid, in light of quite recent developments, and possibly is worth pursuing further in a more formal context.
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I think we are off chasing a red herring similar to the Gordon Broen radio interference herrings in the BA038 incident.This base is NOT new and it lies directly beneath the flightpath from DPS-PER. As far as I am aware, none of these flights have fallen from the sky over the years?
Autopilot disconnected just like the Skippy bird did.
USA was full of 9/11 hysteria so the co-pilot had to be blamed.
USA also has OTHR radar over the Atlantic like the Jindalee system. UK also has an OTHR system pointed towards the Atlantic.
There are a lot of vested interests from Governments to aircraft manufacturers out there who don't want to admit that electronic interference can flip out systems on commercial airliners.
Red Hear-ings
B][QUOTE]kiwiguy:
How about Egyptair flight 990 ?
Autopilot disconnected just like the Skippy bird did.[/QUOTE]
er, did you ever look at the DFDR of that plane? or hear the CVR? if not, please refrain from sprouting nonsense.
[The QAR records the methods of disconnect.... which kinda blows a "whole" in your supposition of commonality or conspiracy or I know not what...]
The parameters of the DFDR were adequate to identify exactly what was being done on the flight controls of MSR 990, and the system behavior was completely consistent with the inputs, as were the flight dynamics. Additionally, please don't bring in any reference to Silkair 185, the data and the dissenting opinion on the report are convincing, as were the mcab flyouts of the reconstruction.
There are adequate real issues to contend with....
How about Egyptair flight 990 ?
Autopilot disconnected just like the Skippy bird did.[/QUOTE]
er, did you ever look at the DFDR of that plane? or hear the CVR? if not, please refrain from sprouting nonsense.
[The QAR records the methods of disconnect.... which kinda blows a "whole" in your supposition of commonality or conspiracy or I know not what...]
The parameters of the DFDR were adequate to identify exactly what was being done on the flight controls of MSR 990, and the system behavior was completely consistent with the inputs, as were the flight dynamics. Additionally, please don't bring in any reference to Silkair 185, the data and the dissenting opinion on the report are convincing, as were the mcab flyouts of the reconstruction.
There are adequate real issues to contend with....
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How about Egyptair flight 990 ?
Autopilot disconnected just like the Skippy bird did.
USA was full of 9/11 hysteria so the co-pilot had to be blamed.
Autopilot disconnected just like the Skippy bird did.
USA was full of 9/11 hysteria so the co-pilot had to be blamed.
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The crew reported that the messages were constantly scrolling, and they could not effectively interact with the ECAM to action and/or clear the messages.
Where is the switch "SVP NO PROTECTION" ?
That FO could almost look suspicious ... left the flight deck only one minute before the initial ECAM FAULT and returned only a full 5 minutes after the first upset ...
Kiwiguy
AFAIK we only had one OTHR and that was at Orford Ness pointing east, as shown in the excellent 'Coast' tv programme.
It didn't work and was dismantled years ago. I believe that there was one planned for the Brawdy area in Wales, but that was never built.
AFAIK we only had one OTHR and that was at Orford Ness pointing east, as shown in the excellent 'Coast' tv programme.
It didn't work and was dismantled years ago. I believe that there was one planned for the Brawdy area in Wales, but that was never built.
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In Australian media the VLF people at the facility near Learmonth have been sort of quoted as saying "we've been there a bloody long time and no aircraft operator has complained, and anyway we are not the only VLF facility located near commercial airways, and none of them have been cited either."
Methinks the ATSB put that reference, plus the one to passenger operated devices, into the report in order to placate who knows who.
They will look at both because they are thorough professionals, but clearly the onboard gear is the prime suspect, and greatest worry.
Methinks the ATSB put that reference, plus the one to passenger operated devices, into the report in order to placate who knows who.
They will look at both because they are thorough professionals, but clearly the onboard gear is the prime suspect, and greatest worry.
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In the light of the report, perhaps someone should open a new thread so that all those who posted that it was CAT and that they should have continued to Perth can post retractions without distracting the VHF brigade?
US NAVCOMSTA Exmouth
I think that it is a real stretch to say that the QF incident might be related to the US NAVCOMSTA at Exmouth Cape.
The recently released initial ATSB report says the incident occurred 154km west of Learmonth. That would make it about 170km W-S-W of the NAVCOMSTA at Exmouth Cape.
This is much further from the transmitter than inferred in reports on this forum.
Here is a ground track of the flight showing where the problem occured.
Had the flight track been directly overhead the transmitter then perhaps there may be some correlation.
Flynerd
The recently released initial ATSB report says the incident occurred 154km west of Learmonth. That would make it about 170km W-S-W of the NAVCOMSTA at Exmouth Cape.
This is much further from the transmitter than inferred in reports on this forum.
Here is a ground track of the flight showing where the problem occured.
Had the flight track been directly overhead the transmitter then perhaps there may be some correlation.
Flynerd
Those of you who like a good conspiracy theory may be interested in this link and the article it links to!
AN AMERICAN VLF TRANSMITTER SITE...OR WAS IT?
AN AMERICAN VLF TRANSMITTER SITE...OR WAS IT?
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Originally Posted by flynerd
The recently released initial ATSB report says the incident occurred 154km west of Learmonth. That would make it about 170km W-S-W of the NAVCOMSTA at Exmouth Cape.
This is much further from the transmitter than inferred in reports on this forum.
This is much further from the transmitter than inferred in reports on this forum.
I'll redo my calculations next week... we have friends for lunch this Sunday.
But applying the usual square law, at first sight you can divide my figures by a hundred.
My figures were based on a near overflight in the main lobe, at aout 15 km range...
Originally Posted by tubby linton
Those of you who like a good conspiracy theory may be interested in this link and the article it links to!
AN AMERICAN VLF TRANSMITTER SITE...OR WAS IT?
AN AMERICAN VLF TRANSMITTER SITE...OR WAS IT?
I absolutely love those conspiracy theories
Have you noticed how often you can just deduct from the mere style of the article, or post, or whatever, that the author is telling porkies?
Much like the intonation of the opening sentence of a telemarketer....
CJ
OTHR Orfordness
didn't work...?
Of historical note only:
Well, the original UK radar trials were conducted at Orfordness with the Radio Research Station setting up from 13 May 1935 on site, under the direction of Sir R. Watson Watt (& Wilkins, Bainbridge-Bell, and Bowen). Initial transmissions were by a transmitter using huge NT46 valves ex navy, at 5,000V input, giving approximately 20-25kW output @ 50mtr freq, which was boosted to 12,000V giving 200kW. The early tests showed echoes from [parts of] Europe over 2,000 miles away. The first aircraft tracked was a Scapa flying boat at a range of 17 miles, on 17 June 1935.
The initial freq selected, 50mtr was expected to give a good return on the dipole resonator of the expected target aircraft wingspan, but due to excessive interference the freq was increased to 26mtr, then 10-13mtr which remained primary radar freq through Round II.
The tactical requirement of the Air Ministry (Dowding) under Tizzard's Scientific Committee's position was to address defense requirements below 100nm. The OTHR effects were identified but discounted as a nuisance at that time.
well before Jindalee was initiated, "woodpecker" interference was received from what was DF'd as USSR on HF freqs, (back in 60's and early 70's), which was consistent with OTHR trials.
ref: Radar Days, E.G. Bowen, Published by Adam Hilger, Bristol UK. 1987 ISBN 0-85274-590-7
Metres to Microwaves, E. B. Callick, Published by Institution of Engineering and Technology, 1990 ISBN 0863412122
Sir Robert Watson-Watt
AAS-Biographical memoirs-Bowen
CSIRO PUBLISHING - Historical Records of Australian Science
Of historical note only:
Well, the original UK radar trials were conducted at Orfordness with the Radio Research Station setting up from 13 May 1935 on site, under the direction of Sir R. Watson Watt (& Wilkins, Bainbridge-Bell, and Bowen). Initial transmissions were by a transmitter using huge NT46 valves ex navy, at 5,000V input, giving approximately 20-25kW output @ 50mtr freq, which was boosted to 12,000V giving 200kW. The early tests showed echoes from [parts of] Europe over 2,000 miles away. The first aircraft tracked was a Scapa flying boat at a range of 17 miles, on 17 June 1935.
The initial freq selected, 50mtr was expected to give a good return on the dipole resonator of the expected target aircraft wingspan, but due to excessive interference the freq was increased to 26mtr, then 10-13mtr which remained primary radar freq through Round II.
The tactical requirement of the Air Ministry (Dowding) under Tizzard's Scientific Committee's position was to address defense requirements below 100nm. The OTHR effects were identified but discounted as a nuisance at that time.
well before Jindalee was initiated, "woodpecker" interference was received from what was DF'd as USSR on HF freqs, (back in 60's and early 70's), which was consistent with OTHR trials.
ref: Radar Days, E.G. Bowen, Published by Adam Hilger, Bristol UK. 1987 ISBN 0-85274-590-7
Metres to Microwaves, E. B. Callick, Published by Institution of Engineering and Technology, 1990 ISBN 0863412122
Sir Robert Watson-Watt
AAS-Biographical memoirs-Bowen
CSIRO PUBLISHING - Historical Records of Australian Science
Last edited by fdr; 17th Nov 2008 at 06:43. Reason: clarification
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Back on the thread ...
from today's Crikey e-zine
Secret data may give Qantas a QF72 clue
Ben Sandilands writes:
A secret partition (internal computer wall) on the US-made air data inertial reference unit (ADIRU) that Qantas blames for the in flight crisis that forced QF 72 to make an emergency landing at Learmonth on 7 October is about to be unlocked.
Its existence, only hinted at in the preliminary ATSB report into the accident, is causing consternation among airlines for whom there is now a question mark over the serviceability of equipment critical to the control of modern airliners. They simply don't know the full information held by the ADIRU.
Crikey has been shown part of a private Qantas presentation on the accident, which injured 60 of its passengers and 14 of its crew aboard the Airbus A330-300 involved.
It draws attention to frequent unusual movements in the tail of the jet and disclosed that all three ADIRU units had be sent back to the maker, Northrop-Grumman because of third level data that was partitioned from examination by operators or accident investigators and could only be read in the Northrop-Grumman workshops.
This deeper level of data is apparently prohibited to users to protect proprietary aspects of the design from being copied or interfered with.
However the issue that has now emerged for the carriers including Qantas is that this secrecy might prevent them becoming aware of any deeper layer faults that should be fixed before an airliner is allowed to continue in service.
The Australian, French and US incident investigation authorities, and Airbus and Qantas will all be present this week when Northrop-Grumman starts unlocking all of the data contained in the three units on the A330, the two that appeared to work properly, and the one that ran amok.
Secret data may give Qantas a QF72 clue
Ben Sandilands writes:
A secret partition (internal computer wall) on the US-made air data inertial reference unit (ADIRU) that Qantas blames for the in flight crisis that forced QF 72 to make an emergency landing at Learmonth on 7 October is about to be unlocked.
Its existence, only hinted at in the preliminary ATSB report into the accident, is causing consternation among airlines for whom there is now a question mark over the serviceability of equipment critical to the control of modern airliners. They simply don't know the full information held by the ADIRU.
Crikey has been shown part of a private Qantas presentation on the accident, which injured 60 of its passengers and 14 of its crew aboard the Airbus A330-300 involved.
It draws attention to frequent unusual movements in the tail of the jet and disclosed that all three ADIRU units had be sent back to the maker, Northrop-Grumman because of third level data that was partitioned from examination by operators or accident investigators and could only be read in the Northrop-Grumman workshops.
This deeper level of data is apparently prohibited to users to protect proprietary aspects of the design from being copied or interfered with.
However the issue that has now emerged for the carriers including Qantas is that this secrecy might prevent them becoming aware of any deeper layer faults that should be fixed before an airliner is allowed to continue in service.
The Australian, French and US incident investigation authorities, and Airbus and Qantas will all be present this week when Northrop-Grumman starts unlocking all of the data contained in the three units on the A330, the two that appeared to work properly, and the one that ran amok.
"The original UK radar trials were conducted at Orfordness ....The early tests showed echoes from Europe over 2,000 miles away."
Suffolk having been transplanted for the tests to the east coast of Canada?
I heard this RFI story from an editor friend who ran the newspaper outside the Bremerton Navy Base in the NW US. When the Associated Press began sending photographs via digital satellite instead of land-line fax around 1990, pictures that arrived around 6 a.m. each day were scambled. As an afternoon paper that printed at 10 a.m., this meant some of the best newsy news pictures from the Gulf War I were getting toasted right on deadline.
After a little investigating he discovered that all the big aircraft carriers in port tested their search radars at 6 ack-emma, and that all of them pointed directly at the newspaper's satellite reception dishes (ships lined up in parallel berths facing the town.) The beams were turning the incoming AP signals into guacamole.
That was at a range of about 1 mile or less, though.
That Crikey story at first listen sounds a bit like finding a false bottom in your wastebasket and blaming it for all your mistyped pages - but maybe it will go somewhere.
Suffolk having been transplanted for the tests to the east coast of Canada?
I heard this RFI story from an editor friend who ran the newspaper outside the Bremerton Navy Base in the NW US. When the Associated Press began sending photographs via digital satellite instead of land-line fax around 1990, pictures that arrived around 6 a.m. each day were scambled. As an afternoon paper that printed at 10 a.m., this meant some of the best newsy news pictures from the Gulf War I were getting toasted right on deadline.
After a little investigating he discovered that all the big aircraft carriers in port tested their search radars at 6 ack-emma, and that all of them pointed directly at the newspaper's satellite reception dishes (ships lined up in parallel berths facing the town.) The beams were turning the incoming AP signals into guacamole.
That was at a range of about 1 mile or less, though.
That Crikey story at first listen sounds a bit like finding a false bottom in your wastebasket and blaming it for all your mistyped pages - but maybe it will go somewhere.
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ATSB Interim Report Issued - March 2009
See new interim report here: aair200806143.aspx
Key new points:
1. Testing discounts Leamonth VLF interference.
2. No fault found with ADIRUs so far; testing continues.
3. PRIMS usually filter spikes from ADIRUs, but fail to filter rare combinations of spikes. Only applies to A330/340.
4. ADIRU 1 generated many spikes. Two sets appear not to have been rejected by PRIMS and resulted in nose-down events. Subsequent events explained by as-designed fall back response.
4. Three other similar incidents (all having no ill effects) uncovered (4 total, all QANTAS or Jetstar)
5. Reproducible situation identified where loosely fastened seatbelts can disconnect if passenger propelled upward.
Curiouser and curiouser...
Key new points:
1. Testing discounts Leamonth VLF interference.
2. No fault found with ADIRUs so far; testing continues.
3. PRIMS usually filter spikes from ADIRUs, but fail to filter rare combinations of spikes. Only applies to A330/340.
4. ADIRU 1 generated many spikes. Two sets appear not to have been rejected by PRIMS and resulted in nose-down events. Subsequent events explained by as-designed fall back response.
4. Three other similar incidents (all having no ill effects) uncovered (4 total, all QANTAS or Jetstar)
5. Reproducible situation identified where loosely fastened seatbelts can disconnect if passenger propelled upward.
Curiouser and curiouser...
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Serious Software problem
I think everyone is missing the point.
The problem is not that the ADIRU 1 sent "erroneous and spike" values. ADIRUs are known to fail occasionally, that's one of the reasons why there are several of them.
This is evidence of a serious flaw in the Airbus FBW control software in the A330/A340 PRIMs (Flight Control Primary Computers).
Spike filtering is essential, and "the manufacturer advised" that there was "an issue" with the software, in which AoA spike values could be passed on to the control algorithms in certain conditions.
It is not unexpected to people involved with high-reliability software for safety-critical systems that it appears to be a requirements/specification problem.
There is a temporal sequence of AoA spike values (I will call it "Critical Spike Value Sequence", CSVS) from the ADIRUs that will get past the spike filtering and be interpreted by the flight control/envelope protection algorithms as real values.
It appears that the software develeopment process at Airbus is not quite what it should be.
Either the algorithms were specified incorrectly and the emergence of CSVS is inherent in the algorithm, or the algorithm was implemented incorrectly, and the emergence of CSVS is an artifact of implementation issues (coding/compiler/linker/hardware). According to the report, Airbus identified a problem with the algorithm, so that points to the first alternative.
Either way it is a strong case for the need to use formal methods for both requirements elicitation, ensuring their completeness
and adequacy, and for implementation, using state-of-the-technology "Correct-by-Construction"-methods.
Bernd
The problem is not that the ADIRU 1 sent "erroneous and spike" values. ADIRUs are known to fail occasionally, that's one of the reasons why there are several of them.
This is evidence of a serious flaw in the Airbus FBW control software in the A330/A340 PRIMs (Flight Control Primary Computers).
Spike filtering is essential, and "the manufacturer advised" that there was "an issue" with the software, in which AoA spike values could be passed on to the control algorithms in certain conditions.
It is not unexpected to people involved with high-reliability software for safety-critical systems that it appears to be a requirements/specification problem.
There is a temporal sequence of AoA spike values (I will call it "Critical Spike Value Sequence", CSVS) from the ADIRUs that will get past the spike filtering and be interpreted by the flight control/envelope protection algorithms as real values.
It appears that the software develeopment process at Airbus is not quite what it should be.
Either the algorithms were specified incorrectly and the emergence of CSVS is inherent in the algorithm, or the algorithm was implemented incorrectly, and the emergence of CSVS is an artifact of implementation issues (coding/compiler/linker/hardware). According to the report, Airbus identified a problem with the algorithm, so that points to the first alternative.
Either way it is a strong case for the need to use formal methods for both requirements elicitation, ensuring their completeness
and adequacy, and for implementation, using state-of-the-technology "Correct-by-Construction"-methods.
Bernd