Sikorsky S-60
... that before the flight test program of the Sikorsky S-60 flying crane was completed, its successor was already on the drawing board?
... that before the flight test program of the <b id="mwAiU"><a href="./Sikorsky_S-60" id="mwAiY" rel="mw:WikiLink" title="Sikorsky S-60">Sikorsky S-60</a></b> <a class="mw-redirect" href="./Flying_crane" id="mwAic" rel="mw:WikiLink" title="Flying crane">flying crane</a> was completed, its successor was already on the drawing board?