Air data inertial reference unit: Difference between revisions

Revision as of 23:47, 31 December 2021

Revision as of 23:55, 31 December 2021

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===Air data reference===

{{See also|Pitot-static system}}

The air data reference (ADR) component of an ADIRU provides airspeed, [[Mach number]], angle of attack, temperature and barometric altitude data. Both the ADIRU and the SAARU transmit voted, high-availability, high-integrity air data to all user systems<ref name="aero-08">

{{cite web

|url=http://www.boeing.com/commercial/aeromagazine/aero_08/erroneous_textonly.html

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==Complexity in redundancy==

Analysis of complex systems is itself so difficult as to be subject to errors in the certification process. Complex interactions between flight computers and ADIRU's can lead to counter-intuitive behaviour for the crew in the event of a failure.

However the ADIRU continued to supply ADR data to the captainpilots's primary flight displaydisplays. In addition, the master flight control computer (PRIM1) was switched from PRIM1 to PRIM2, then PRIM2 back to PRIM1, thereby creating a situation of uncertainty for the crew who did not know which redundant systems they were relying upon.<ref name="harmful">

{{cite web |url=http://www.dcs.gla.ac.uk/~johnson/papers/ISSC09/ADIRU_Accident_Submission.pdf |title=The Dangers of Interaction with Modular and Self-Healing Avionics Applications: Redundancy Considered Harmful |author1=C.W. Johnson |author2=C. Michael Holloway |date=2 February 2009 |access-date=8 June 2009}}</ref>

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==Failures and directives==