Phugoid

Imagine you're on a swing set, and you want to go higher and higher. You swing up and then back down, but you don't stop at the bottom. Instead, you swing back up again but not as high as before.

This back-and-forth motion is similar to an airplane in flight that's experiencing a phugoid. A phugoid is a flight pattern that planes can experience when they are moving up and down in the air. It's caused by the plane's natural desire to stabilize itself.

The phugoid is like a swing set because the airplane goes up and down in a repeating way. The difference is that the phugoid has more than two cycles. The pilots call these cycles "oscillations."

If the pilot does not control the phugoid, it can be dangerous because the plane's altitude will vary too much. This can cause the plane to stall, which means it stops flying and starts falling.

So, to summarize, a phugoid is a repeating motion that an airplane experiences when it moves up and down in the air. It's like a swing set, but more complicated. Pilots need to control phugoids to keep the plane flying safely.