Open — within standard operating limitations
Open applies only when all §107.10(a) limits are satisfied. These include an aircraft under 25 kg, VLOS operation, and operation at or below 120 m (400 ft) AGL by day, together with the other limitations in the regulation.
Open operations still retain pilot-certificate, registration-where-applicable and Permit-to-Operate requirements.
Specific — outside standard limits or more complex operations
An operation enters Specific when the aircraft is between 25 and 150 kg or the operation falls outside the standard Open limits. GACA guidance gives examples such as BVLOS and certain night, near-aerodrome or over-people operations depending on the approved scope.
Specific can require category-specific pilot certification, additional training/endorsements and operational authorization or operator certification.