DO-254 defines 3 types of verification methods: Analysis, Test and Review. In order to satisfy the verification objectives defined in DO-254, applicants must formulate a requirements-based verification plan that employs a combination of the three methods.
Analysis vs. Test
A computerized simulation of the hardware item is considered an Analysis. Test is a method that confirms the actual hardware item correctly responds to a series of stimuli. Any inability to verify specific requirements by Test on the device itself must be justified and alternative means of verification must be provided. In DO-254, the hardware test is far more important than the simulation. Certification authorities favor verification by test for official verification credits because of the simple fact that hardware flies, not simulation models. Requirements describing pin-level behavior of the device must be verified by hardware test.