Cardinal 177/177RG
Flight Crew Flight Instructor; Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Air Transport Pilot (ATP)
Flight Crew Last 90 Days 20; Flight Crew Total 6300; Flight Crew Type 900
Troubleshooting
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport
Aircraft
Flight was intended to be a VFR local flight to exercise the aircraft [after sitting for an extended period]. Conducted a normal pre-flight. Engine start; runup; and before takeoff check were normal. Oil Pressure was in range and the prop cycled through three times with no irregularities. Started takeoff roll on runway XX. All engine instruments in green (including oil pressure) and airspeed alive. Rotated for normal takeoff and at approximately 400 feet checked the engine instruments again as is my procedure. Oil temp OK; oil pressure Zero. Called tower and informed them that I had zero oil pressure and would be coming back to land on runway XX. Tower cleared me to land on any runway. Climbed to approximately 500 feet on downwind and reduced power slightly. Oil temp remained normal and the engine ran normally. Tower asked if I needed anything else and I replied I was OK. Abeam the numbers I began a continuous left turn to final and selected flaps 20. Touched down on the numbers and turned off at the second taxiway. Estimated I was in the air approximately 90 seconds after observing the zero oil pressure indication. Taxied a short distance to park at idle power. Engine had 1950 hours on it so if the oil pressure had actually been zero; the next step is an overhaul before the next flight. However; post flight inspection revealed that the oil pressure transducer had failed. The part was date stamped 1976 so it had served reliably for 44 years. A replacement kit was ordered and installed by the local FAA repair shop.Tower controller deserves a big thank you. They were professional and allowed me to get the aircraft on the ground safety in the shortest amount of time. They gave just the right amount of response and were available for any of my needs.
Pilot reported that shortly after takeoff the engine oil pressure indication dropped to zero and a successful return to the airport was done. Postflight maintenance inspection revealed that the oil pressure transducer had failed.