As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
LNK - FLT 3222 - IN CRUISE, THE LT RPM GAUGE BEGAN TO FLUCTUATE. NO OTHER ENGINE FLUCTUATIONS NOTED. THE ACFT RETURNED TO MSP. MAINTENANCE WAS UNABLE TO DUPLICATE THE DISCREPANCY. THE SYSTEM OPERATED SATISFACTORILY DURING A TEST FLIGHT. (W)