Last weekend I was flying in support of a thousand-mile offroad truck and motorbike race in Baja California, in a type of helicopter known in America as an A-Star (in Europe it goes by the French word for squirrel.) In my headset I hear the communication with air traffic control from one radio; the air-to-air communication between helicopters on a second radio; the chatter of the race team on the third. And I also hear the muted, ambient buzz of both the air conditioner and the engine oil cooling fan motors.
Several hours into the day as we’re following our race truck through a canyon I hear a soft, quick pop!/clank! The loudness of the buzz lessens almost imperceptibly, but its tone noticeably shifts. Several minutes later the oil temperature begins to rise.
I landed and shut down at the next fueling stop—an orchard field tucked into a remote hillside—and called the mechanic. He directed me to turn the battery back on, lick my fingers, and then reach in behind the oil cooler reservoir and touch the two exposed wire leads of the oil temperature sensor.
I licked, and touched, and was not electrocuted. An old A-Star trick to test the oil cooler I hadn’t known about.