SR20
Flight Crew Commercial; Flight Crew Flight Instructor
Confusion; Troubleshooting
Aircraft Equipment Problem Less Severe
Flight Crew Diverted; Flight Crew Landed As Precaution; General Maintenance Action
Aircraft; Human Factors
Enroute instructor noticed that the engine was running abnormally loud and checked engine power level. Power level read 20% and 1400 RPMs with 11 GPH fuel burn and 123 KIAS. Noting abnormal indications; Instructor Pilot (IP) told student to fly direct [to home field]. During the flight back; power was set to minimum cruise 100 Knots to reduce any engine strain and monitored all instruments; everything was normal aside from Power % and Tach. Aircraft was told to expect the arrival. Instructor requested straight in as a better option but was told unable (Approach was unaware of the issue at this time); about 20 seconds after this statement; instructor and pilot both felt an unusual knock; that was enough for instructor to call for a diversion to the nearest airport. Pilot told Approach that we were not stating an emergency but we were receiving unusual engine indications and was diverting with 2 souls and 3 1/2 hours of fuel.
Reporter believed that the low power level readings were caused by a faulty sensor which lead to an assumption that the engine was about to fail. It was deemed better to land and have it checked out.
SR20 instructor with student reported a low power reading in cruise and elected to divert to the nearest suitable airport.