A M-20J pilot noticed his oil pressure drop rapidly at cruise; so diverted to a nearby airport. Ther...

Attributes
ACN	1284384
Time
Date	201507
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	M-20 J (201) / Allegro
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Oil Storage
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Instrument Flight Crew Private
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 1500 Flight Crew Type 300
Events
Anomaly	Aircraft Equipment Problem Critical Deviation - Procedural Other / Unknown

Narrative:

I was 15 mile northeast 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.

Original NASA ASRS Text

Title: 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.

Narrative: 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.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

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.