Energy Management Considerations

Why it's necessary to think about total energy management.

Tip Energy Management Considerations

Tip Energy Management Considerations

What makes an airplane climb? The answer might seem obvious, until you consider all the factors that allow us to gain altitude.

The addition of engine power is the answer that probably popped into your head first. Yet in light GA airplanes, altitude gain can also be achieved by taking advantage of thermal updrafts, reducing drag, and using potential and kinetic energy to initiate a zoom climb — a favorite topic of discussion in Wolfgang Langewiesche's seminal book "Stick and Rudder."

Why is this important? On approach it's necessary to think about total energy management when making altitude and airspeed corrections. If you're too low what should you do? Add power? Pull back on the yoke?

That depends. After all, there's a big difference between being low and slow and low and fast. Altitude and airspeed together provide you with your total mechanical energy. It's why you need to look at both the altimeter and airspeed indicator to determine how you should manipulate the controls to get back on a proper glidepath.

If you're right on your target airspeed and configured for landing, you can think of the throttle a little like the controls on a freight elevator. Pull back on the throttle to go down, push forward to stop going down. If you're too high or too low, and also too fast or too slow, a combination of throttle and yoke (and perhaps flaps and gear) can be used to put you back on your target approach speed and glidepath.

The trick is in considering your total mechanical energy to apply just the right power and pitch inputs to keep you in the altitude/airspeed sweet spot.

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