The LTN-101 air data inertial reference unit (ADIRU) model had a demonstrated susceptibility to single event effects (SEE). The consideration of SEE during the design process was consistent with industry practice at the time the unit was developed, and the overall fault rates of the ADIRU were within the relevant design objectives.
The theoretical analysis was an assessment of the potential for SEE to have an influence. It did not actually reduce the potential of SEE for existing units.
The ADIRU manufacturer conducted a ‘theoretical analysis’ of the potential for a single event upset (SEU) on the LTN-101 ADIRU. The overall result of this analysis was that, after considering the influence of SEEs, the ADIRU still met the aircraft manufacturer’s safety objectives.
