corrective action....
The proper corrective action in case of ground resonance in a 269 series helicopter is not to simply "get it in the air"...
Granted, that is one of them...you get it in the air if the RPM is in the green operating range....2500-2700 if I remember correctly (300CB/CBi numbers)
If the RPM is not in the green you immediately roll the throttle off, to cut the power, that will also stop the resonance.
But be quick
Timts