What was found
RETURNED TO DEPARTURE, DUE TO THE FIRST OFFICER MACH AIRSPEED INDICATOR FAILURE. REPLACED THE C581 CIRCUIT BREAKER, RIGHT ADC AND RIGHT MASI. SYSTEM OPERATION IS NORMAL.
As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
RETURNED TO DEPARTURE, DUE TO THE FIRST OFFICER MACH AIRSPEED INDICATOR FAILURE. REPLACED THE C581 CIRCUIT BREAKER, RIGHT ADC AND RIGHT MASI. SYSTEM OPERATION IS NORMAL.