Aero Commander 500 Series
Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument
Flight Crew Last 90 Days 240; Flight Crew Total 5020; Flight Crew Type 480
Situational Awareness
Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Air Traffic Control Issued New Clearance; Flight Crew Diverted; Flight Crew Inflight Shutdown; Flight Crew Landed in Emergency Condition; Flight Crew Landed As Precaution
Aircraft; Human Factors
I had just reduced the manifold pressure in anticipation of a descent. I noticed that the oil pressure needle was starting to drift down on the starboard engine; and the manifold pressure needles had split slightly and risen slightly on the starboard engine. I elected to shut down the starboard engine per the checklist; and continue the flight. As it was night; and the terrain was mountainous; I asked ATC for a diversion to the nearest airfield for a precautionary landing. ATC gave a vector heading to the airfield. I requested some landing information from ATC. That bought me time to review the airport on the chart. The winds were calm so a straight in approach was selected. The approach and landing was uneventful.Post flight revealed that the oil dipsticks were not properly installed; and oil had siphoned out in flight. I disobeyed my own rule of not letting anyone interrupt me during a preflight; and had walked away from my airplane. Being night time; discrepancies were harder to spot. I should have redone the preflight from the beginning. For sure; I will not let this happen again. Finally; thanks to ATC for being so helpful; and the hospitality of the ground crew.
An AC50B pilot reported inflight shut down of the right engine as a precaution when discrepancies were noted in oil pressure and manifold pressure.