Category Description RC MTBF MTTR
Functional model Goal: Testing of concepts
Testing of selected components for suitability to the concept
Very limited range of functions
Assume low reliability of the system
>50% < 7 d < 14 d
Prototype Goal: Testing of the concept
Validation of the suitability of the components
Validation of the functions and the technical requirements
>80% < 30 d < 7 d
Pre-series Goal: Testing of the entire range of functions
Endurance testing of the system in various application scenarios
Validation of the safety functions
>95% < 90 d < 3 d
Series Goal: Product stand for end customers
Quality proofs according to the specifications
Series parts, series status released
>99% > 365 d < 2 d

RC = Requirements Coverage
MTBF = Mean Time Between Failure
MTTR = Mean Time To Repair