This is a Significant Operational milestone.
The aircraft was piloted by Leonard LaVassar. The aircraft first flew in 1957, and completed 34 transitions between vertical and horizontal flight before it was retired from service on April 16, 1964. It was also used as a trainer for the XC-142.
Source: "Leonard LaVassar, Test Pilot", VERTIFLITE May/June 2016, Page 59