About the green arc probably you should read more carefully the official Tecnam POH (as reported following) White arc 45 - 96 Positive Flap Operating Range (lower limit is VSO, at specified maximum weight and upper limit is the maximum speed permissible with landing flaps extension). Green arc 50 – 107 Normal Operating Range (lower limit is VS1 at specified maximum weight and most forward e.g. with flaps retracted and upper limit is maximum structural speed VNO). Yellow arc 107 – 135 Manoeuvres must be conducted with caution and only in smooth air. Red line 135 Maximum speed for all operations.