M-20 J (201) / Allegro
Flight Crew Instrument; Flight Crew Private
Flight Crew Last 90 Days 50; Flight Crew Total 1500; Flight Crew Type 300
Workload; Situational Awareness; Training / Qualification; Human-Machine Interface
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Other / Unknown
Flight Crew Diverted; Flight Crew Landed in Emergency Condition; Flight Crew Took Evasive Action
Aircraft
I was 15 Mile NE of a suitable airport at 10;000 MSL; 2.5 hours into a 4:50 Hour flight when I noticed Oil Pressure dropping rapidly. I requested vectors to the nearest suitable airport and was given clearance to descend to 3000 feet and vectors to the airport; 15 Miles South. I turned and started decent to approximately 6500-7500 feet when I told ATC I would stop descent to stay in gliding distance if the engine quit. The remainder of the flight was uneventful and I landed on Runway XY. Upon examination the Oil Quick Drain Valve was found broken off. Its threads were still in the Oil Pan but the drain was gone. We don't know why this happened. I can't suggest any steps to avoid recurrence. Prior training I had in handling emergencies was very helpful as was layout of engine indicating instruments being right in front of pilot allowing easy scan and my habit of doing so.
A M-20J pilot noticed his oil pressure drop rapidly at cruise; so diverted to a nearby airport. There he discovered the Oil Quick Drain Valve broken off but the threads still in the oil pan.