Simple Plug Checker: Go/No-Go on Resistance

摘要

The list of approved maintenance items an aircraft owner can do under FAR Part 43 is long and includes replacing, cleaning and gapping plugs. In the spirit of cleaning, we think checking plug resistance is also on the list. Like lowering your cholesterol and cutting back on salt intake, plug resistance wasn't always a con-cern, or at least one that anyone bothered with. But with the widespread use of engine monitors that can detect the slightest combustior anomalies, spark plug resistance has become the latest fine-point maintenance item owners need to worry about. What's the problem here? As we reported in the November 2012 issue of Aviation Consumer, aviation spark plugs have a built-in resistor to keep the spark from becoming too energetic, which will prematurely erode the electrodes. However, if the resistance is too high, excessive lead fouling, inconsistent plug firing and high CHTs may result.