Although barely two years have elapsed since the helicopter was first certificated for civil use, the problem associated with its operation are sufficiently well defined to enable their nature to be discussed with reasonable facility Actually, of course, there are twenty-six years, including many tens of thousands of flying hours behind this particular development, and it is quite logical therefore that the most advanced and successful type of helicopter to date embodies the basic and well proven rotor features of the Cierva Autogiro

There is still much to learn, however, and at this stage of development it has in many ways been advantageous that, so far, the field of operational use has been a professional one Difficulties have been minor rather than of a major category, but circumstances could easily have been otherwise had there not been constantly available the requisite background of skill and experience not only to cure, but what is of equal importance, to anticipate and prevent trouble before it could assume proportions of a serious nature Additionally the limited number of helicopters in use has encouraged and made possible a rather intimate and desirable liaison between constructor and operator, which in turn has given the aircraft a reasonable opportunity to establish itself and prove its value under strictly controlled conditions of inspection and operation