by Greg Lewis

In this third in a series of articles exploring what makes an aircraft good to fly on instruments in weather, we’ll address aircraft dynamics. Our first two articles discussed static stability (pitch stability, July 2004; lateral-directional stability in September 2004).

Static stability is about what initially happens if an aircraft is disturbed from some steady starting point. The example used was the ball in a cup, as shown below. If the black ball starts at the bottom of the cup and is then moved up the side and released, the ball will start moving downhill back towards its starting point. That’s a definition of static stability: “An object displaced…