Alpha Model
Input Parameters: α1, α2, ..., αn
Unavailability of CCF events:
Where:
= The probability of having a failure of multiplicity k.Therefore:
The FTA module allows you to enter any positive value for αk and 
need not be 1.
need not be 1.The FTA module takes care of this situation by normalizing the α values. Only α1, α2, α3, and α4 are accepted as inputs. If the number of components () is more than 4, then αi = 0 is used for i > 4. If i < 4, only the appropriate parameters are used. For example, for n = 3, α1, α2, and α3 are used.
For n = 4:
Input Parameters: α1, α2, α3, α4
Unavailability of CCF events:
Where:
