The Binomial Failure Rate model is also known as a shock model. The input parameters and calculations for the unavailabilty of CCF events for the Binomial Failure Rate model are:

Q1 is the independent failure probability of each component, p is the conditional probability of failure of each component (given a non-lethal shock), QSH is the occurrence probability of non-lethal shock, and QLS is the occurrence probability of lethal shock. Therefore, Qt=Q1+pQSH+QLS.

If n = 4, then the input parameter and calculations for the unavailability of CCF events would be: