While the subject of this colloquium is limited to reliability, I feel it is essential to put this parameter in its right context as we as users in the RN see it.

We in the RN are most concerned with the availability of our aircraft to perform the required operational task. We define availability as the percentage of a given period of time that an aircraft is either being used or is serviceable ready for use. If availability is low then we need a larger number of aircraft to meet a commitment. With the cost of current aircraft and our restrictions on carrier complements this is a vital consideration.