6.1.7.1 Effect of failure/consequence/impact. 6.1.7.1.1 History of the occurrences. 6.1.7.1.2 Similarity of types and failures/defects. 6.1.7.1.3 Associated number of operational personnel. 6.1.7.1.4 Frequency of the operation. 6.1.7.1.5 Threat factors.