Given two options to classify likelihood, which one should we use? Should we use the criteria
based on the number of operations or that based on the period? When the risk is associated with
aircraft operations, the likelihood definition to be applied will depend on the volume of operations
at the airport. If the volume of operations is small, the likelihood definition based on time
should be used. At larger airports, a criterion based on the number of departures is the correct
one to apply. As a rule of thumb, airports with less than 200 departures per day should use likelihood
definitions based on the expected period for an event to occur