MAINTENANCE ITEM #10

*** LOW OIL PRESSURE LIGHT ***

By Lee Beery

Have you ever had a trip planned and as you start your preflight you discover to your horror that you failed to turn off the master switch after your last flight and now you have a dead battery? I hate to admit it, but yours truly has done this several times. This and the fact that three aircraft with no oil pressure (no engine rotation) have been forced down at our airport in the past year or so, prompted me to take the following action.

I installed an aircraft system warning light (Grimes makes several types) in the instrument panel in the lower left corner. This light uses a "grain of wheat" bulb that can be replaced by removal of the amber color cover. Also, the base of the light does not provide the lights ground as it has two terminals, one for power and the other for ground. I chose to power the light by connecting a wire to the fuel gauge power terminal so it would have fuse protection. I then provided a ground for the light by running a wire to the engine hour meter oil pressure switch. Now when engine oil pressure drops to 4 pounds, the warning light electrical circuit is completed and the light is illuminated. If you don't have an oil pressure switch, one can easily be installed by removing the oil gallery plug located close by the left magneto and install switch at that location.