Confusion on TSO's seems rampant. It reminds me of the confusion over
"mass" and "weight".



TSOs are the Technical Standards that a device must meet to be
considered to be said device by the FAA. TSO compliance has little to
do with reliability.



DO160 is a collection of tests that can be performed on a device
to demonstrate that it is robust. Being able to pass these tests is an
indicator of how reliable a device will be once installed.



DO178 controls the testing and certification of software.



Certification is a process by which you demonstrate to the FAA that
a given device complies with the applicable TSO and/or will pass the
applicable DO160 tests and/or will satisfy the applicable DO178 level
standards.



Reliability is a generic qualitative term that implies a device
will perform as expected when subjected to anticipated conditions. Can
you rely on a device to perform as expected.



Robustness or ruggedness is a device's ability to
perform after being subjected to conditions beyond what is normally
anticipated.



A device can comply with a TSO and not be TSOed. A device can pass
DO160 testing and not be "Certified".



Regards

Brent Regan