When the aircraft carries serviceable Mode C transponder, the pilot shall continuously
operate this mode:
a. Only when directed by ATC
b. Unless otherwise directed by ATC
c. Only when the aircraft is flying within controlled airspace
d. Regardless of ATC instructions
operate this mode:
a. Only when directed by ATC
b. Unless otherwise directed by ATC
c. Only when the aircraft is flying within controlled airspace
d. Regardless of ATC instructions