AD 2005-18-51 - rolls back software updates 3470-HNC-100-04 to -07 to old version :
"Install OPS, part number (P/N) 3470-HNC-100-03, in the air data inertial reference unit (ADIRU)" which will "reintroduce unsafe condition" "potential drift angle discrepancies on the primary flight display and the navigation display"
with this comment further down:
"We consider this AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD (2005-18-51) and AD 2005-10-03. Once this modification is developed, approved, and available, we may consider additional rulemaking".
I can't find any more ADs or Service Bulletins regarding the 777 ADIRU, from those in 2005 to now. I think I am correct in saying that the Operation Manual changed to make pilot's aware of the issue and how to work around any problems that came up.
Could a combination of all of these known issues have overwhelmed the workload of the pilots causing them to struggle with controlling the plane and unable to go through checklists?
Thanks very much for this! I look forward to giving this paper a careful read. I see that on CW Johnson's web page he says: "The main focus for my research is at the interface between safety and security - for example, developing techniques so that we can continue to ensure safety while gathering forensic evidence in the aftermath of a cyber-attack." He could have some very interesting things to say...
In-flight upset of 9M-MRG (Malaysia Airlines Flight 124) Aug 2005. This is the only 777 ADIRU issue I could find, coincidence and/or informative?
Accident report:
https://www.atsb.gov.au/sites/default/files/media/24550/aair200503722_001.pdf
AD Aug/Sept 2005 - The NOT Fix
AD 2005-18-51 - rolls back software updates 3470-HNC-100-04 to -07 to old version :
"Install OPS, part number (P/N) 3470-HNC-100-03, in the air data inertial reference unit (ADIRU)" which will "reintroduce unsafe condition" "potential drift angle discrepancies on the primary flight display and the navigation display"
with this comment further down:
"We consider this AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD (2005-18-51) and AD 2005-10-03. Once this modification is developed, approved, and available, we may consider additional rulemaking".
I can't find any more ADs or Service Bulletins regarding the 777 ADIRU, from those in 2005 to now. I think I am correct in saying that the Operation Manual changed to make pilot's aware of the issue and how to work around any problems that came up.
Then this Paper was produced : The Dangers of Failure Masking in Fault-Tolerant Software: Aspects of a Recent In-Flight Upset Event https://ntrs.nasa.gov/api/citations/20070034017/downloads/20070034017.pdf
It appears that the ability to accept 'faulty' information and display erroneous heading data seems to be possible in 2014. Additionally there were display screens blanking, mention of this post-disappearance, can be found here: https://www.federalregister.gov/documents/2014/10/01/2014-23231/airworthiness-directives-the-boeing-company-airplanes.
Could a combination of all of these known issues have overwhelmed the workload of the pilots causing them to struggle with controlling the plane and unable to go through checklists?
Thanks very much for this! I look forward to giving this paper a careful read. I see that on CW Johnson's web page he says: "The main focus for my research is at the interface between safety and security - for example, developing techniques so that we can continue to ensure safety while gathering forensic evidence in the aftermath of a cyber-attack." He could have some very interesting things to say...