Post #3 – Failure during test…but not in real world usage

How is it possible that during the avionics and pitot-static test, equipment may fail without any previous known incidents? For starters: Certification specifications are follow more demanding rules compared to some operational requirements. This is done to help detect and rectify issues before they can ever become an issue. Example #1 Some transponders have a significant amount of drift. If the unit exhibits drift slightly out of the design tolerances, the unit will still function normally. Such unit will fail the avionics test due to the drift being out-of-spec. The transponder can be corrected or repaired to ensure proper function during flight. Example #2 While slightly off of the allowable…