TBM700 pilot experiences oil pressure decreasing and then a fluctuating torque indication upon level...

Attributes
ACN	1065666
Time
Date	201302
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.ARTCC
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	TBM 700/TBM 850
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Route In Use	Direct
Flight Plan	IFR
Component
Aircraft Component	Oil Filler Cap
Person 1
Function	Pilot Flying Single Pilot
Qualification	Flight Crew Commercial Flight Crew Flight Instructor Flight Crew Instrument Flight Crew Multiengine
Experience	Flight Crew Last 90 Days 40 Flight Crew Total 4500 Flight Crew Type 5
Events
Anomaly	Aircraft Equipment Problem Critical

Narrative:

[I] took off in a tbm-700c2; with two passengers on board plus myself. The plan was to drop off one passenger and then continue back home. Leveling off at FL270 [around 20 minutes into flight]; about 15 miles southeast of [an enroute airport]; I noticed the oil pressure decreasing and then a fluctuating torque indication. As I reduced power; the red oil pressure annunciator illuminated. I immediately requested a descent and diversion into [the enroute airport]. Oil pressure stabilized near; but above; red line at the reduced power setting. Conditions were VMC; made a visual approach into [the airport] and landed without incident. Upon inspection; I discovered the oil cap was not fully tightened; causing the leak.

Original NASA ASRS Text

Title: TBM700 pilot experiences oil pressure decreasing and then a fluctuating torque indication upon leveling off at FL270. A diversion to the nearest suitable airport is initiated with the engine continuing to run with oil pressure just above minimum. Post flight reveals the oil tank cap is not fully tightened.

Narrative: [I] took off in a TBM-700C2; with two passengers on board plus myself. The plan was to drop off one passenger and then continue back home. Leveling off at FL270 [around 20 minutes into flight]; about 15 miles southeast of [an enroute airport]; I noticed the oil pressure decreasing and then a fluctuating torque indication. As I reduced power; the red oil pressure annunciator illuminated. I immediately requested a descent and diversion into [the enroute airport]. Oil pressure stabilized near; but above; red line at the reduced power setting. Conditions were VMC; made a visual approach into [the airport] and landed without incident. Upon inspection; I discovered the oil cap was not fully tightened; causing the leak.

Data retrieved from NASA's ASRS site as of July 2013 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.