2.4 Risk estimation
Risk estimation is done by analyzing the two components of the probability and consistent, namely:
• Likelihood
Likelihood is the probability of a risk that can occur in a component in a given period [1]. Likelihood estimation is calculated by using the data report diaries control room [4][5]. From the data failure of each component at a certain period of time, the value of Mean Time to Failure (MTTF) as the average time that a component failure is determined. Likelihood value is obtained from the comparison between the amount of the daily operations of the MTTF value overall production period, in one day running the production company for 24 hours. Furthermore, the likelihood is determined level. The likelihood calculation follows the following equation: