This is a Notable Operational milestone.
This was a tethered flight. It was also the first time a helicopter had flown with the Bell stabilizer bar rotor system. The aircraft was known as Ship 1 and it was a tethered flight. The aircraft first flew untethered on June 26, 1943.
Source: “Bell Model 30 ‘Genevieve’ ”, Paul Fardink, VFS 2019 VTOL History Calendar